ISSN 0003-1216

10 FEB 1982 LIBRARY & INFORMATION SERVICES JOURNAL

OF THE AMERICAN SOCIETY

OF SUGAR BEET TECHNOLOGISTS

OCTOBER 1981 VOL. 21, NO. 2 EXECUTIVE COMMITTEE

President Stewart Bass American Crystal Sugar Co. Moorhead, Minnesota

Vice President Robert E. Munroe Riley Stoker Corporation Northglenn, Colorado

Secretary-Treasurer James H. Fischer Beet Sugar Development Foundation Fort Collins, Colorado

Immediate Past President M. A. Woods Union Sugar Company Santa Maria, California

BOARD OF DIRECTORS

Pacific Coast Region: David H. Eddington

lntermountain Region: Raymond G. Larson

Eastern Rocky Mountain

Region: J. P. Abbott

North Central Region: Gordon Rudolph

Great Lakes Region: R. N. Sanborn

Canada: G. M. Guccione

Processing at Large: Clair H. Iverson

Agriculture at Large: Donald L. Oldemeyer

Manuscripts submitted for publication and communications pertain- ing to editorial, matters should be sent to James H. Fischer, Secre- tary-Treasurer, American Society of Sugar Beet Technologists, P. 0. Box 1546, Fort Collins, Colorado 80522.

Each manuscript received for publication will be appraised for its technical and historical value by a Publications Committee. The Publications Committee shall have final authority regarding publi- cation of manuscripts. The Journal of the American Society of Sugar Beet Technologists shall contain papers presented at General and Regional meetings and articles of immediate interest prepared specifically for this periodical. ISSN 0003-1216 JOURNAL of the American Society of Sugar Beet Technologists

Volume 21

Number 2

October 1981

Published semi-annually by American Society of Sugar Beet Technologists Office of the Secretary P.O. Box 1546 Fort Collins, Colorado 80522

Subscription prices: $4.50 per year, domestic $5.00 per year, foreign $2.50 per copy, domestic $2.80 per copy, foreign

Made in the United States of America CONTENTS

Method of Phosphorus Fertilization for Sugarbeets in the J. T. Moraghan Red River Valley J. D. Etchevers 103 Postemergence Weed Control with Combinations of Herbicides in Different Sugarbeet Planting L. M. Burtch Periods B. B. Fischer .

Habit Modifications of Sucrose Crystals Andrew VanHook 130 An Analysisof Root Damage Charles L. Peterson During Piling...... Eldon R. Muller 136 Mark C. Hall Joseph C. Thompson Effect of Nitrapyrin on Uptake of Nitrogen by Sugarbeet from Labeled F. J . Hill s Ammonium Sulfate A. Abshahi 150 F. E. Broadbent G. A. Peterson Effects of Lime on the Chemistry of Sugarbeet W. M. Camirand Tissue J. M. Randall E. M. Zaragosa H. Neuman Fusarium Stalk Blight Resistance in Sugarbeet. . .J. S. McFarlane 175 Effects of Sugarbeet Sample Preparation and Handling on Sucrose, Nonsucrose R. J. H ecker and Purity Analyses . . . . S. S. Martin 184 Method of Phosphorus Fertilization for Sugarbeets in the Red River Valley*

J.T. Moraghan and J. D. Etchevers

Received for Publication March 27, 1980 INTRODUCTION Most studies involving rates and methods of phosphorus (P) fertilization of sugarbeets in the United States have been conducted under irrigated conditions. The sugarbeet crop in the Red River Valley of North Dakota, Minnesota and Manitoba is grown largely under dryland conditions where topsoils, after an effective leaf canopy has been established, often have low quantities of avail- able soil moisture. Successful sugarbeet production is dependent upon utilization of stored subsoil moisture (10). Sugarbeets usu- ally responded to row applications of superphosphate in the early years of the industry in the region (12).

Low soil temperatures increase the likelihood of P deficiency in sugarbeets (15). Etchevers (6) found that higher rates of P fertilizer were needed to optimize early sugarbeet growth as soil temperatures were reduced from 16 to 7 C. According to Sample (13) band or seed application of P fertilizer may be beneficial in regions where cold or wet springs affect early growth. Sugarbeets utilized more t'-tagged fertilizer during the first four weeks of a greenhouse study when the fertilizer was placed either 5.1 or 10.2 cm below the seed as compared to a sideband application 5.1 cm to the side and 5.1 cm below the seed (1). Results of field experiments with sugarbeets in Michigan supported this finding (A). Sidebanded or row applications, how­ ever, are sometimes still preferred since disturbance of the soil at a depth near the line of seed sowing may affect emergence (5); this is especially relevant since precision planting is becoming

*Published with the approval of the Director, North Dakota Agr. Exp. Stn. as Journal Series No. 1129 . The authors are Professor, Department of Soils, North Dakota State University, Fargo, ND 58105, and Professor of Soils, University of Concepcion, Cillan, Chile. 104 JOURNAL OF THE A.S.S.B.T.

of increasing importance to producers. A great deal of work has been conducted on method of place­ ment of P fertilizer, particularly under irrigated conditions. Results have been variable and in many cases yield differences were small (14). Cope and Hunter (3) suggested that small re­ sponses both to application and placement cf P fertilizer under British conditions were due to the extensive nature of the sugar- beet root system. Irrigated sugarbeets reportedly are unlikely to respond to P fertilizer in Washington (9) and Idaho (17) when soil NaHCO - extractable P (11) levels in the surface soil are greater than 10 ppm. The critical value for irrigated sugarbeets in Utah was given as 12.5 ppm NailCO3 -extractable P (8). The relationship between reponscs to broadcast and incorporated fertilizer by dry- land sugarbeets in the Red River Valley and NaHCO -extractable P was studied by Etchevers (6) and is illustrated in Figure 1; sugarbeets growing in soils containing over 10 ppm extractable P seem unlikely to respond to broadcast fertilizer.

Figure 1. - Relationship between relative responses of sugarbeets to P fertilizer under field conditions and NaHCO3-ex- tractable P.

Recent data pertaining to responses to P fertilizer and method of application for sugarbeet production in the Red River Valley are sparse. The objective of the present study was to com- pare the efficacy of banded triple superphosphate with broadcast and incorporated application of the same material on soils with VOL. 21, NO. 2, OCTOBER 1981 105

selected levels of NaHCO3-extracta ble P.

MATERIALS AND METHODS

Four field experiments, one in 1975 and three in 1976, were

established at sites with NaHCO3 -P levels (11) as given in Table 1. The experimental design was a randomized block with a split- plot arrangement of treatments. Broadcast and incorporated P fertilizer (0, 11, 22, 45, and 90 kg P/ha or 0, 10, 20, 40, and 80 lbs P/A) and banded fertilizer (0 and 11 kg P/ha) were the whole- and split-plot treatments, respectively. Each treatment was replicated six times. The experimental plot at Site 1 con­ sisted of six 9-2-m rows spaced 75 cm apart; the plots at Sites 2, 3 and 4 were eight 13.6-rn rows spaced 56 cm apart.

The broadcast P treatments were applied to the soil surface in the fall of the year prior to the experiment. The fertilizer was incorporated up to a depth of approximately 10 cm by use of a cultivator. The banded treatment was applied 5 cm to the side and 5 cm below the seed at planting by means of belt attachments to the planter and separate disc openings. A population of 58,000 plants per ha was established in all plots by thinning. A basal dressing of nitrogen, based on soil nitrate contents in the upper 61 cm of soil, was applied to the soil at all sites. Petioles from recently mature leaves were sampled several times during the growing season, dried at 60 C, ground to pass a sieve with 0.5-mm openings, and analyzed for acetic acid ex- tractable phosphate (7, 16). For root yield determinations at Sites 1, 2 and 3, two 5.0-m sections of the center rows were harvested and weighed. A subsample of 20 roots was taken and analyzed for percentage sugar and impurities. The final root yields at Site 4. were obtained similarly except that the lengths 106 JOURNAL OF THE A.S.S.B.T.

of the harvested rows were 7.6 m. Sugar losses were determined by the impurity approach of Carruthers and Oldfield (2). The impurity index ratio was defined as: 3-5xppm Na + 2.5xppm K + lOxppm amino-N Impurity Tndex = —-—— — %sugar RESULTS AND DISCUSSION

GROWING SEASON CONDITIONS Precipitation during the growing season was 9«7» 15-0, 8.1 and 14.0 cm at Sites 1, 2, 3 and 4, respectively. During most of July and. August total soil moisture in the 0 to 15-cm depth in­ crement, the zone where the fertilizer was located, at Sites 1 and 3 below the 15-bar matric potential.

ROOT AND SUGAR YIELDS The influence of method of application of P fertilizer on yield of sugar and roots is given in Table 2. Phosphorus fertil­ izer significantly increased yields of both roots and sugar only at Site 1, the site with the lowest value, 4 ppm, of NaHCO~ -ex- tractable P. Percentage sugar and the impurity index were not affected by P treatment at any site.

Table 2. - Influence of rate and method of phosphorus fertilization on yield and related characteristics of sugarbeets at four sites.

a"x" and "y" denote that either 0 or 11 kg P per ha, respectively, was applied 5 cm to the side and 5 cm below the seed. To convert from metric tons (T)/ha to tons/acre multiply T/ha by 0.446. VOL. 21, NO. 2, OCTOBER 1981 107

Side-banded application of 11 kg P per ha at Site 1 signifi- cantly increased recoverable sugar yields at the 0, 11 and 45 kg P per ha broadcast levels; the banded application had no sig- nificant effect on sugar yield at the highest rate of broadcast P. The banded application of 11 kg P per ha was significantly more effective than the same quantity broadcast at this site. In fact, this banded rate was equivalent or superior to the 45 kg P per ha rate. There was a tendency for P fertilizer to increase root and

sugar yields at Site 2, where the NaHCO3-extractable P was 10 ppm. The effect of banded P fertilizer averaged over broadcast rates on root yields was significant at this site. Data showing the influence of banded phosphorus fertilizer averaged over the broadcast rates are given in Table 3.

Table 3. — Influence of a banded phosphorus fertilizer treatment averaged over several broadcast. phosphorus fertilizer treatments on the yield of sugar and related character- istics at four sites.

Root Impurity Rec. Band P yield Sugar index sugar kg/ha T/ha % kg/ha Si te 1 37,. 0 18.4 37 5 6310 39,. 0 18.3 364 6830 1,. 3 NS NS 340 Site 2 30,. 0 16.8 732 4470 31,. 8 16.6 782 4720 1 .,1 NS NS NS Site 3 38,. 1 19.9 412 7110 38,. 5 19.9 411 7180 LSD (0.05) NS Site 4 37.2 19.1 367 6710 27.4 19.1 393 6640 LSD (0.05)

PLANT ANALYSIS DATA The effect of fertilizer treatments on acetic acid extractable phosphate in recently mature sugarbeet petioles during the growing season is illustrated in Table 4. Principal Conclusions from these data were: 10 8 Table 4. Influence of rale and method of phosphorus fertilization on acetic acid soluble phosphorus (AcOH-P) in petioles of recently mature sugarbeet leaves during the growing season at four sites.

a"I" and "II" represent broadcast and incorporated phosphorus fertilizer, and banded 5 cm to the side and 5 cm JOURNA L O F TH E A.S.S.B.T . below the seed, phosphorus fertilizer, respectively. VOL. 21, NO. 2, OCTOBER 1981 109

a. Extractable phosphate values were higher in petioles from Sites 3 and 4 where no response to phosphate fertilizer was obtained. b. Banded P fertilizer was particularly effective at increas- ing plant, phosphate at Site 1, the low soil phosphate site. The banded treatment was more effective in increasing plant phosphate than was up to 45 kg P per ha applied broadcast and incorporated. c. Acetic acid extractable plant phosphate decreased during the growing season at all four sites. Phosphate values below 750 ppm P, the reported critical value for this element (16), were found at all sites during portions of the growing season. Data from the four experiments suggest that the critical value for plant phosphate-P decreased during the growing season under the given conditions. The critical value at Site 1 appeared to be between 1470 and 1770 ppm in mid-July, soon after the establishment of a complete leaf canopy; in contrast, the value dropped to between 430 and 620 ppm P late in the growing season. The plant anal- ysis data from the other sites generally support these conclusions. Westerman et al. (17) recently provided extensive plant analysis data for sugarbeets grown under irrigated conditions in Idaho where acetic-acid extractable phosphate contents of petioles of recently mature leaves also decreased during the growing sea- son. Sugarbeets did not respond to P fertilization in the irrigated study if the petioles contained more than 1200 ppm phosphate-P in early July and 700 ppm phosphate-P in late August. Decreases in petiole P values in the dryland Red River Valley studies were larger than those for the irrigated study. This was probably due to shortages of available topsoil moisture detrimentally affecting the availability of native and fertilizer P during the latter part of the growing season. Luxury uptake of P early in the growing season may be needed under some conditions in the Red River Valley in order to insure adequate plant P later, when soil moisture shortages restrict P uptake from the topsoil.

SUMMARY The influence of method of application on the response of sugarbeets to P fertilizer, triple superphosphate, was studied in four field experiments on soils containing 4, 10, 10 and 12 ppm 110 JOURNAL OF THE A.S.S.B.T.

NaHCO3 -extractable P. Yield of recoverable sugar was increased by P fertilization of the soil with the lowest test value. On this latter soil 11 kg P per ha banded 5 cm to the side and 5 cm below the seed was equal or superior to the application of 45 kg P per ha broadcast and incorporated in the upper 10 cm of soil. Acetic acid extractable phosphate-P in petioles from recently mature leaves decreased during the growing season. The levels of petiole phosphate-P above which sugarbeets did not respond to fertilizer were approximately 1500 ppm and 500 ppm for leaves samples soon after establishment of a complete leaf canopy in mid- July and in late August or early September, respectively. Lack of available soil water in soil zones where P fertilizer is located probably influence critical plant P values in the Red River Valley. Banding some of the P fertilizer would appear to be ag- ronomically efficient on soils in the region with relatively low levels of NaHCO3 -extractable P. The alternative in such cases is to apply larger quantities, up to 90 kg P per ha, of broadcast and incorporated fertilizer.

ACKNOWLEDGMENTS

The authors wish to thank the American Crystal Sugar Co. for the sugar analyses. Sincere appreciation is also extended to Mr. Paul Tiedeman and Miss Sue Olerud for their technical and secretarial help, respectively.

LITERATURE CITED (1) Anderson, F.N. and G.A. Peterson. 1978. Optimum starter fertilizer placement for sugarbeet seedlings as determined by uptake of radioactive 32p isotope. J. Am. Soc. Sugar Beet Technol. 20:19-24.

(2) Carruthers, A. and J.F.T. Oldfield. 1961. Methods for assessment of beet quality. Int. Sugar J. 63:137-139. (3) Cope, F. and J.G. Hunter. 1967. Interactions between nitrogen and phosphate in agriculture. International Super- phosphate Manufacturers' Association Ltd. Agricultural Com- mittee (Paris) "Phosphorus in Agriculture" Bull. 46. (4) Davis, J.F., G. Nichol, and D. Thurlow. 1961. The inter- action of rates of phosphate application with fertilizer place- ment and fertilizer applied at planting on the chemical com- position or sugar beet tissue, yield, percent sucrose and apparent purity of sugar beet roots. J. Am. Soc. Sugar Beet Technol. 12:259-267. VOL. 21, NO. 2, OCTOBER 1981 111

(5) Draycott, A. P. , M. J. Durrant, and D.A. Boyd. 1971. The relationship between soil phosphorus and response by sugar- beet to phosphate fertilizer on mineral soil. J. Agric. Sci. (Camb.) 77:117-121. (6) Etchevers, J.D. 1977. Response of sugarbeets to phosphorus fertilization. Ph.D. Thesis, North Dakota State University

(7) Etchevers, J.D., J.T. Moraghan, and I.R. Chowdhury. 1978. Analysis of sugarbeet petioles for phosphorus. Commun. Soil Sci. Plant Anal. 9:905-914. (8) Haddock, J.L. 1959. Yield, quality and nutrient content of sugarbeets as affected by irrigation regime and fertilizers J. Am. Soc. Sugar Tech. 10:344-355- (9) James, D. W., G.E. Leggett, and A.I. Dow. 1967. Phos- phorus fertility relationships of Central Washington irrigated soils. Washington Agr. Exp. Sta. Bull. 688. (10) Morgahan, J.T. 1972. Water use by sugar beets in a semi- arid environment as influenced by population and nitrogen fertilizer. Agron. J. 64:759-762. (11) Olsen, S.R., C.V. Cole, F.S. Watanabe, and L.A. Dean. 1954 Estimation of available phosphorus in soils by extraction with sodium bicarbonate. USDA Circ. 939. (12) Rost, CO., H.W. Kramer, and T.M. McCall.. 1948. Fertili- zation of sugarbeets in the Red River Valley. Minnesota Agr. Exp. Sta. Bull. 399. (13) Sample, E.C. 1979. Assessing agronomic factors. p. 24- 31. In Situation 79. Proc. TVA Fertilizer Conference, St. Louis, MO.

(14) Schmehl, W.R. and D.W. James. 1971. Phosphorus and pot- assium nutrition. p. 138-169- In R.T. Johnson et al. (eds.) Advances in Sugarbeet Production: Principles and Practices. The Iowa State Univ. Press, Ames. (15) Sipitanos, K.M. and A. Ulrich. 1971. The influence of root zone temperature on phosphorus nutrition of sugarbeet seed- lings. J. Am. Soc. Sugar Beet Tech. 16:409-421.

(16) Ulrich, A., D. Ririe, F.J. Hills, A.G. George, and M.D. Morse. 1959- 1. Plant Analysis. A guide for sugarbeet fertilization. Cal. Agr. Exp. Sta. Bull. 766. (17) Westerman, D.T., G.E. Leggett, and J. N. Carter. 1977. Phosphorus fertilization of sugarbeets. J. Am. Soc. Sugar Technol. 19:262-269. Postemergence Weed Control with Combinations of Herbicides in Different Sugarbeet Planting Periods

L. M. Burtch and B. B. Fischer *

Received for Publication March 9, 1981 The mild climate of California permits the planting of sugarbeets from late August through June. The same climatic conditions that favor sugarbeet culture also stimulate the germintion and growth of many broadleaf weeds and grasses. The challenges and methods of weed control vary widely with the time of planting. Consequently, no single herbicide or application method provides season-long control for any of the major planting periods. Therefore, growers need to carefully select fields and adopt weed control programs to provide economic and effective weed control for their individual growing conditions. Postemergence weed control has been widely accepted since the development of phenmedipham (Betanal) and desmedipham (Betanex) (.3, 11, 12, 14). These two herbicides control a wide range of broadleaf weed species, but they are not effective on grasses (4, 5, 7, 12, 15). The ad- vantages of a postemergence herbicide are numerous. The most obvious is that weed problems can be identified before the herbicide is applied. This permits the selection of the most effective herbicide, or combination of herbicides to control specific weed problems (13). Postemergence appli- cations also require less energy and time than preplant incorporated treatments (6, 8). Since grasses and broadleaf species usually emerge at the same time, it would be desirable to have an effective grass herbicide which could be combined with Betanal and/or Betanex.

*Chief Agronomist, Spreckels Sugar Division, Amstar Corporation, Mendota, CA and Farm Advisor, University of California, Fresno, CA, respectively. VOL. 21, NO. 2, OCTOBER 1981 113

The search for an effective grass herbicide has been an ongoing goal for a number of years, starting with dalapon [Dowpon (2)J and propham (Chemhoe) and continuing with diclofop-methyl (Hoelon), ethofumesate (Nortron) and several promising compounds (8, 9, 12).

Three new herbicides have recently been made available for evaluation as potential grass killers (10). They are BAS-9052 (Poast), RO-13-8895 and KK80. After its evaluation in several trials where it appeared promising, KK80 was withdrawn by its developer. The purpose of these studies was to compare the ef- fectiveness of several herbicides applied singly, or in combi- nation with Betanal plus Betanex for control of barnyardgrass (Echinochloa crusgalli L.), as well as mixed populations of broadleaf weeds and grasses. A series of 10 experiments, conducted over a two-year period, are summarized in this report.

MATERIALS AND METHODS

The herbicides were applied with a CO2 constant pressure backpack sprayer. Each trial was replicated three or four times. Individual plots were two rows wide and 30 or 40 feet long. Row spacings were single-row beds, spaced 30 inches apart, or two rows on 40-inch beds spaced 14 inches apart. The herbicides were applied broadcast or in 12-inch bands in 35 to 50 gallons of water per acre. At time of treatment, sugarbeets ranged from the 2- to 6-leaf stage of growth. In one trial, sugarbeets had 8 to 10 leaves. Barnyardgrass was the principle weed, however, volunteer cereals and other annual grasses were present in some trials. Broadleaf weeds varied from common winter annual species, such as black mustard (Brassica nigra L., Koch), shepherd's purse (Capsella bursa pastoris L., Medic) and fiddleneck (Amsinckia intermedia F&M) and summer annuals such as lambsquarters (Chenopodivm sp.), pigweeds (Amaranth sp.), and purslane (Portulaca oleracea L.).

Seven herbicides were evaluated for grass control alone and in combinations with Betanal plus Betanex. 114 JOURNAL OF THE A.S.S.B.T.

Adjuvants X-77 or pace (paraffin base petroleum oil 83%, polyal fatty acid esters of polyethoxylated derivatives 15%) were added, except when the grass herbicides were combined with Betanal or Betanex. Appropriate weed control and sugarbeet injury evaluations were made. Beet injury ratings were based on a 0-10 scale, with "0" indicating no injury, and 10 complete kill. Weed control ratings were visual estimates expressed as percent control. Treatments and rates are given in the table that summarize the results. The results from each experiment are summarized in a table bearing the same number. Experiment 1 was established on March 12, 1979 on sugarbeets in the 2-4 leaf stage and infested with 2-4 inch tall barnyardgrass. The temperature was 65 F. Experiment 2 was established on March 30, 1979 in a field infested with barnyardgrass, johnsongrass (Sorghum halepense L.) and redroot pigweed (Amaranthus retroflexus L.). Grasses were less than 1.5 inches high with sugarbeets in the early 2-leaf stage. Experiment 3 compared Poast and KK80 with Hoelon in a trial established on June 8, 1979. The principle weeds present were purslane and barnyardgrass. Temperature was 95 F at 2 p.m. when the herbicides were applied. Beets were mostly in the 4-leaf stage with weeds ranging from 2 to 4 inches high and under moisture stress. Experiment 4 was established on May 31, 1979 in a field severely infested with barnyardgrass ranging in size from 3 to 12 inches tall with beets in the 8-10 leaf stage. The experiment was replicated 4 times and carried to harvest. The remaining experiments were conducted between March and July of 1980 and were designed primarily to evaluate Poast and RO-13-8895 singly and in combination with Betanal and Betanex.

Experiment 5 was established on March 7 on a winter planted field having a variety of broadleaf and grassy weeds such as: sand spurry (Spergularia ruba L.), pine- apple weed (Matricaria matricarioides ) knotweed (Polygonum VOL. 21, NO. 2, OCTOBER 1981 115

aviculare L.), clover (Trifolium sp.), wild oats Mvena fatua L.), rabbitsfoot grass (Polypogon monspeliensis L., Desf. ), prickly lettuce (Latuca scariola L.). Sugarbeets were in the 6-leaf stage with weeds ranging from newly emerged to approximately the size of the beets. Experiment 6 was established in the early afternoon of June 12 when the temperature was 76 F. The beets had 2-4 leaves. Nortron, Poast, and RO-13-8895 were applied in combi- nation with equal amounts of Betanal plus Betanex.

Experiment 7 established June 27, contained combination treatments and sequential applications. Two rates of Poast and RO-13-8895 were applied singly and in combination with Betanal plus Betanex. After a delay of five days, Betanal plus Betanex were applied sequentially to the areas treated with grass herbicides. Poast. and RO-13-8895 were superimposed on the Betanal plus Betanex treatments. Experiment 8 was established on June 12 when the sugar- beets were in the 4-leaf stage. Barnyardgrass was growing vigorously and equal in height with the beets. Two rates of Poast and RO-13-8895 were applied in the late afternoon when the temperature was 76 F.

Experiments 9 and 10 were established on the same planting of sugarbeets, but at two stages of growth. Experi- ment 9 was initiated on June 20 when sugarbeets were in the 2-4 leaf stage, and the barnyardgrass and redroot pigweed were 1 to 3 inches tall. Five days later in an adjacent area, an additional trial was conducted. Temperatures ranged from 80-85 F on the afternoons when each experiment was initiated.

OBSERVATIONS AND RESULTS Experiment 1. Barnyardgrass was not adequately con- trolled with either Dowpon or Hoelon (Table 1). Combination of Hoelon plus Betanal or Betanex provided 85 to 88% barnyard- grass control 14 days after application. Experiment 2. Excellent control of young barnyardgrass and johnsongrass resulted three weeks after applying HOE 29152, Hoelon or Hoelon plus Betanex (Table 2). Dowpon plus Betanex and Nortron provided less effective grass control and produced 116 JOURNAL OF THE A.S.S.B.T.

more initial injury to sugarbeets. These two experiments con- firm results from earlier trials that neither Nortron nor Dowpon effectively control barnyardgra .ss (2, 5, 9). Hoelon did not control barnyardgrass beyond the 2-leaf stage of growth.

Table 2. A comparison of several postemergence treatments for control, of newly emerged Ba rnyardgrass and Johnsongrass (Experiment 2).

Evaluated 4/7 Evaluated 4/20 Rate Beet Grass Beet Grass Treatment Lb ai/A Injury Control Injury Control

a - X-77 at .5% of spray volume was added. Established: 3/30/79. Temp. 6 5 F.

Experiment 3. Barnyardgrass control was excellent with Poast and the higher rate of KK80 (Table 3). Hoelon provided ineffective control of the larger grasses. Treatments containing Betanex were phytotoxic to sugarbeets under the moisture and temperature stress condition existing when the herbicides were applied. Control of purslane, however, was satisfactory, and the surviving sugarbeets recovered rapidly although severe loss of stand occurred. a - X-77 at 0.5% of spray volume was added. Established: 6/8/79. Temp. 95 F. 11 7 118 JOURNAL OF THE A.S.S.B.T.

Experiment 4. Outstanding barnyardgrass control resulted from single applications of Poast at 1 and 2 lb ai/A applied on well established barnyardgrass (Table 4). Excellent control was maintained through August probably because the dense mat of dead grass and sugarbeet foliage inhibited additional barnyardgrass seed germination. The results from this experiment are noteworthy because a hand crew was removed from the section of the field containing the plot because the cost of control was exceeding the expected value of the crop. The yields suggest that a single appli- cation of Poast could have saved the severely infested portions of the field from abandonment.

Table 4. The influence of posteme. rgence chemical control of Barnyardgrass on sugarbeet. yields (Experiment 4).

a - X-77 added at 0.5% of spray volume. Established 5/31/79. b - Vigor reduced by grass competition. Experiment 5- Excellent weed control was achieved with combinations of Betanal plus Betanex with Poast or KK80 (Table 5) - The three-way combination of Betanal plus Dowpon and H273 resulted in poor weed control and greater sugarbeet injury. Experiment 6. The relationship between temperature and sugarbeet injury with herbicide combinations involving Betanal and Betanex was again demonstrated (Table 6). Very little injury and rapid sugarbeet recovery was obtained without stand loss in Experiments 1, 2, and 5, but severe injury resulted at the higher temperatures encountered in Experiments 3 and 6. This confirms earlier work with Betanal and Betanex combinations leading to the practice of delaying applications until afternoon in order to minimize crop damage Table 5. Efiect of Postemcrgence herbicides on weed control and beet injury (Experiment 5)

Evaluated 3/14 Evaluated 3/24 Barnyard Barnyard Beet Grass Broadleal Beet Grass Broadleaf Rate Injury Control Control Injury Control Control. Treatment Lb ai/A

Betanel + 0.75 Betanex + 0.75 1.3 73 73 0.3 96 91 Poast 0.5

Betanal + 0.75 Betanex + 0.75 1.3 77 77 0.3 100 90 Poast 1.0

Betanal + 0.75 Betanex + 0.75 1.3 73 70 0.6 95 88 KK80 1.0

Betanal + 0.75 Betanex + 0.75 2.0 73 73 1.1 96 90 KK80 2.0

Betanal + 1.0 H273 + 0.75 2.7 53 70 1.1 60 70 Dowpon 2.0

Untreated 0.3 0 0 0 0 0

Established: 3/7/80. Temp. 65 F. 11 9 120 JOURNAL OF THE A.S.S.B.T.

(1, 8, 9). The treatments were applied between 1 and 2 p.m. with temperatures in the mid-seventies and the sugar- beets were in the their 2-4 leaf stage. Excellent weed control was obtained, but it resulted in severe reduction in beet stand. The relationship between the size of beet and weeds for effective control is critical. Broadleaf weeds, especially pigweeds and purslane, rapidly develop beyond the stage when effective control can be obtained with Betanal plus Betanex. Limited experience with Poast or RO-1308895 indicates that vigorous growing grasses, espsecially barny ardgrass, can be effectively controlled at a later growth stage. These observations suggested that sequential applications may be desirable, or necessary under some circumstances. Experiment 7. In the sequential application of the herbicides, the best overall weed control was achieved when Betanal plus Betanex proceeded the grass herbicide application (Table 7). Treatment with Poast and RO-1308895 at 0.5 lb ai/A resulted in excellent barnyard grass control. When the grass herbicides were combined with Betanal plus Betanex, excellent broadleaf control was obtained; however, initial beet injury and stand loss occurred. The least beet injury occurred when the grass herbicide preceeded the Betanal plus Betanex application. Barnyardgrass control was somewhat less satisfacatory than when Betanal plus Betanex preceeded the grass herbicide applications. Sugarbeet recovery was rapid following all herbicide applications, however, further work is necessary to explain the apparent differences between Poast and RO-13-8895 when they are applied in combination with Betanal plus Betanex. The results did confirm the initial premise that the broadleaf application should preceed the grass herbicides in sequential treatments. This procedure should result in maximum weed control with minimum beet injury.

Experiment 8. Excellent barnyardgrass control was obtained with both Poast and RO-13-8895 (Table 8). Although VOL . 21 , NO 2 OCTOBE R 198 1

Table 6. Effect of postemergence herbicides on weed concrol. and sugarbeet injury (Experiment. 6). 12 1 12 2

Table 7. Effect of sequential applications of postemergence herbicides on weed control and beet injury (Experi­ ment 7). JOURNA L O F TH E A.S.S.B.T . VOL . 21 , NO 2 OCTOBE R 198 1

Table 7. Continued. 12 3 N Untreated a - Beet vigor indicates recovery from initial injury with 10 - complete recovery. 124 JOURNAL OF THE A.S.S.B.T.

RO-13-8895 stunted sugarbeets more severely than did Poast; no significant stand loss occurred and complete recovery- was obtained within 21 days after the applications.

Table 8. Effects of two experimental herbicides on barnyardgrass control and beet injury (Experiment 8).

Rate Evaluated 6/20 Treatment Lb a i /A Beet Injury Barnyardgrass % Poast + Pace 0.5 + 1 Qt 1.5 80 Poast + Pace 1.0 + 1 Qt 1.2 87 RO-13-889 5 + Pace 1.0 + 1 Qt 4.5 88 RO-13-889.5 + Pace 2.0+ 1 Qt 5.0 96 Untreated 0.5 7 Established: 6/12/80. Temp. 76 F.

Experiment 9. The data developed confirms earlier observations that Poast causes somewhat less beet injury than RO-13-8895 when the herbicides are applied singly (Table 9). Combinations of these two grass herbicides with Betanal plus Betanex resulted in more sugarbeet injury, but better weed control. More beet injury and poorer barn- yardgrass control resulted when Hoelon or Nortron were combined with Betanal plus Betanex.

Experiment 10. Delaying the applications five days resulted in slightly less beet injury with no apparent loss in weed control. This trial included comparisons of two surfactants, X-77 and Pace, with RO-13-8895. Evaluations on July 2nd indicated that Pace was a safer adjuvant to use with this herbicide than X-77, however, without a surfactant, less effective grass control was obtained.

SUMMARY AND CONCLUSIONS

A number of postemergence weed control trials were conducted over a two-year period in the Central Valley of California. Several herbicides selected for their ability to control annual grasses were evaluated. All of the grass herbicides, except HOE 29152, were also tested in combination with Betanal and Betanex to study their effect on the sugarbeet as well as their effectiveness in controlling broadleaf weeds and grasses. It was demonstrated that: VOL . 21 , NO 2 OCTOBE R 198 1

Table 9. Effect, of posternergence grass herbicides and combinations on weed control and beet injury (Experi­ ment 9). 12 5 12 6

Table 9. Continued.

Established: 6/20/80. Temp. 80 F. JOURNA L O F TH E A.S.S.B.T . VOL. 21, NO. 2, OCTOBER 1981

Table 10. Effect of postemergence grass herbicides and combi- nations on beet injury and weed control (Experi- ment 10).

Established: 6/25/80. Temp. 85 F. 128 JOURNAL OF THE A.S.S.B.T.

(1) Poast and RO-13-8895 are very effective poste- mergence grass herbicides. They controlled a wide spectrum of annual grasses, except annual bluegrass, with adequate sugarbeet safety. KK80 also exhibited effective grass control and selectivity on sugarbeets only slightly below that obtained with Poast and RO-13-8895. HOE 29152 provided less effective control than the other herbicides evaluated.

(2) Dowpon, Hoelon, and Nortron failed to control annual grasses as well as the new experimental herbicides. Hoelon was effective only against very young barnyardgrass.

(3) Poast. and RO-13-8895 proved to be very effective when combined with Betanal and Betanex in controlling both grasses and broadleaf species. (4) Betanal plus Betanex, and the grass herbicides applied sequentially, offer a possibility of minimizing sugarbeet symptoms to tolerable levels during periods of high temperatures.

(5) Poast and RO-13-8895 provided effective control of barnyardgrass when treatment was delayed past its seedling stage. Betanal and/or Betanex, however, are most effective on seedling broadleaf weeds. Therefore, the sequence of treatments would favor early applications of Betanal plus Betanex followed by the grass herbicide. More data is required before conditions which favor sequential applications and combinations can be precisely defined. (6) Timing of all postemergence applications of herbicides whether they are used singly or in combination is critical with regard to sugar- beet safety and weed control efficiency. Crop injury is intensified during periods of high temperatures. LITERATURE CITED (1) Bethlentalvay, Gabor and R. R. Norris. 1975. Phytotoxic action of desmedipham: Influence of temperature and light intensity. Weed Science 23:499-503.

(2) Burtch, L. M. and Carlson, C. M. , 1959, Yield compari- sons from chemically and handweeded sugarbeets under several watergrass conditions in California. J. Am. Soc. Sugarbeet Tech.

(3) Dawson, J. H. , 1975. Cycloate and phenmedipham as complemtary treatments in sugarbeets. Weed Sci 23:478-485. VOL. 21, NO. 2, OCTOBER 1981

(4) Dexter, A. G. 1977. "Weed control with postemergence herbicides on sugarbeets in west central Minnesota. S. Beet Res. & Ext." Rep. Vol 8:61-63.

(5) Dexter, A., Schroeder, G. , and Weinlaeder, 1978. Importance of timeliness of Betanex, Betanal and Betanex-Betanal.

(6) Fischer, B. B., Burtch, L. M., and Smith, R. 1975. The control of weeds in beets - a progress report, Runcina:3 UCCE Fresno. (7) Fischer, B. B., Burtch, L. M., and Smith, R. 1976. The science and art of weed control in sugarbeets- a progress report. Runcina:7 UCCE Fresno. (8) Fischer, B. B., Burtch, L. M., and Smith, R. 1977- The role of selective herbicides in sugarbeet. production- a progress report. Runcina:14 UCCE Fresno. (9) Fischer, B. B., Burtch, L. M., and Smith, R. 1978. Effective methods of weed control in sugarbeets - a progress report, Runcina:19 UCCE Fresno. (10) Fischer, B. B., Burtch, L. M. and Brown, L. M. 1980. Sugarbeet applied researcn studies - weed control- mildew control. A progress report, Runcina:21 UCCE Fresno.

(11) Schweitzer, E. F. , and D. M. Weatherspoon, 1971. Response of sugarbeets and weeds to phenmedipham and two analogues. Weed Sci. 19:635-639. (12) Schweitzer, E. E., 1974. Weed control in sugarbeets with cycloat.e, phenmedipham and EP-475- Weed Res. 14:39-44. (13). Schweitzer, E. E., 1980. Herbicides applied sequentially for economic control of annual weeds in sugarbeets. Weed Science 28 (2):152-159. (14) Sullivan, E. F. and Downing, S. L. 1978. Efficacy of preplant Nortron + Hoelon and other mixtures 1975-77. J. Am. Soc. Sug. Beet Tech. 20:175-191. (15) Winter, S. R. and Wiese, A. F., 1978. Phytotoxicity and yield response of sugarbeets (Beta vulgaris) to a mixture of phenmedipham and desmedipham, Weed Sci. 26:1-4. Habit Modifications of Sucrose Crystals

Andrew VanHook *

Received for Publication March 12, 1981 INTRODUCTION Casual inspection of most crops of crystals, including sugar, usually suggests a rather uniform appearance in shape. More careful scrutiny, though, (or better, measurement to discriminate subjective differences due to size) reveals this to be not exactly so. Differences are accentuated when the crystals are grown under non-uniform conditions. This is especially pronounced when the batch is developed without stirring, such as on a microscope slide. The variations persist even when the syrup is seeded; for now the non- uniformity of the seed stock is superimposed upon other variations in growth conditions. In fact, subtle differences occur in the best grown single crystals. Certainly, Kucharenko's (6) specimens are some of the best known of these, vet they exhibit variations in the di mensionless shape of as much as 6 units about the

average of 69.93 ± 1.62 cm6/g2 However, even more pronounced than these differences which may be considered minor and due to variations in seed and growth stabilities, is the influence of impurities. The best known examples of these are the influences of raffinose and dextran on the shape of sucrose crystals but there are many others. RAFFINOSE

This is probably the most carefully studied of sucrose crystal modifiers. It has been considered in detail by Hungerford and Nees (4), Vavri necz (18), and Mantovani (7), amongst many others, and the needle like form produced

*The author is Professor Emeritus, Chemistry Department, College of the Holy Cross, Worcester, MA 01610. VOL. 21, NO. 2, OCTOBER 1981 131

in its presence is well known to all sugar men. This en- longated shape results from the preferential adsorption of raffinose especially on the girdle faces of the crystal where fructose-fructose interactions seem likely (13). This impedes their rate of advance and hence areal enlargement. This stereospecific adsorption has been demonstrated chromato- graphically (16). Smyth (13), as well as Mantovani (8) and Kelly and Mak (7), have pointed out the conformation of molecular structure of adsorbant and crystal structure of adsorbate in this and other cases and this plausibly accounts in part for the stereospecific interaction. Incidentally, this partial chemical and structural simi- larity raises the question whether or not raffinose might not act as a heterogeneous nucleating agent for sucrose crystallization and vice versa. When first tried this was found to be so, but after recry stallizing the seed stock and working in effectively sterile conditions to avoid the sugar dust ever present in any sugar labroatory, it. was found ineffective. The disregistry in crystal lattice dimensions is just too great! Since raffinose occurs throughout a doped crystal and not superficially on the surface, as do many other impurities, one would expect some distortion of the basic sucrose lattice structure on account of the difference in overall molecular size and structure (15). However, this could not be found in a careful x-ray examination (17) of a single crystal of sucrose containing 0.3% raffinose. This had been grown from a syrup containing 5 g. raffinose per 100 g. water. The difference calculated for straightforward substitutional incorporation of this amount of raffinose is less than 0.005A, which was beyond the limit of detection of the equipment available. Neither could the powder x-ray methods available be expected to reveal this small amount of impurity, so that the question still remains open (15)- Essentially the same conclusion was reached by Robinson (10), in Brisbane, who examined in the same way a crystal grown in the presence of dextran. Sketchy phase rule work on the sucrose-raffinose-water 132 JOURNAL OF THE A.S.S.B.T.

systems suggests than any raffinose co-crystallized with sucrose under ordinary equilibrium conditions would be in the form of the pentahydrate. However, no evidence for this could be found from moisture determinations and differ- ential thermal analysis behavior. But again, the effects can be estimated to be at the limit of sensitivity of these methods so that improved or other devises will be necessary to answer this intriguing question more definitively. Another interesting thing about sucrose-raffinose syrups- Sarig and Mullin (11) have recently reported that crystal habit modifiers frequently caused a considerable reduction in size of crystal slurries when gently agitated. The following account illustrates Lhis to apply for raffinose containing slurries; probably as a result of attrition and recrystallization. This hypothesis is indicated by results with NaCl and different habit modifiers: That is, salt, which normally crystallizes as cubes, comes down as octahedra in the presence of urea and as fragile dendrites when even small amounts of fer- rocyanide ion are present. The relative reduction is much greater in this case than with the control or added urea.

Original coarse, granulated 10% through 40 mesh Tumbled 3 days in saturated syrup 15% " " " Same + 5 g. raffinose/100 water 30% " " "

Fine granulated 1.4% through 100 mesh Tumbled 3 days 5.6% " " " Same + raffinose 9.7% " " " DEXTRAN Dextran as impurity causes as much concern in the cane segment of the industry as does raffinose in the beet. It causes elongation c-wise, just as rafinose extends the crystal along the b-axis. This is probably the result of preferential adsorption on the polar faces but this has not been specifically demonstrated. Dextran is particularly obnoxious because it increases the viscosity of syrups tre- mendously along with the other problems of modified crystals. It can be destroyed enzymatically (5) and so can raffinose and starch; although much of the latter can be more effectively removed by good clarification. After all, this step is as important in purifying sugar by removal of impurities as VOL. 21, NO. 2, OCTOBER 1981 133

is the crystallization itself where sucrose is separated from impurity. OTHER CASES The effect of many other substances on the shape of sucrose crystals has been investigated by many technologists (2, 3, 12) in addition to those already cited. In most instances, though, their influence is not as marked as that of the polysaccharides already mentioned. Prisms, triangles, plates, pyramids, twins and other forms are not uncommon but the causative agents have not always been identified. This is important to know should efforts be intended to alleviate the effects of these agents. A special case reported by Sutherland (14) in 1969 is the development of elongated crystals by cyclic dissolution and growth. The change occurs because dissolution is diffusion controlled and the same for all facts whereas growth is not.

Figure 1. Repeated growth and dissolution ot a crystal- idealized.

Along somewhat similar lines and suggested by a pro- cedure utilized by Accorsi and Mantovani (1) to determine the rates of growth of different faces, one can visibly demon- strate crystal form modification by preventing growth of 134 JOURNAL OF THE A.S.S.B.T.

different faces with a coat of varnish. This may have to be refurbished periodically to reduce distortion by overlap, etc. LITERATURE CITED (10 Accorsi, C. A. and G. Mantovani, 1971. Growth Rates of Different Faces of Sucrose Crystals. Z. Zuckerind, 21. (9) 440. (2) Bartens, A. 1974. The Distribution of Non-Sucrose Substances in Sucrose Crystals. Z. Zuckerind, 99 (11) 575. (3) Delavier, H. S. , and collaborators. 1974. Habit Modi- factions. Z. Zuckerind, (24&7) 574, 639. (4) Hungerford, E. H. and A. R. Nees, 1936. Raffinose. Ind. Eng. Chem., 26, 462. (5) Inkerman, P. A. 1980. An Appraisal of the Use of Dextranose. ISSCT, Manila. (6) Kelly, F. H. C. and F. K. Mak, 1974. The Kucharenko Papers. Int. Sugar J., J6_, 201. (7) Kelly F. H. C. and F. K. Mak, 1975. The Sucrose Crystal. Singapore Univ. Press. (8) Mantovani, G. , G. Gllli and F. Fagioli, 1967. Habit Variation of Sucrose. Compt. Rend. XIII Assembly CITS (Falsterbo) CITS Tienen, Belgique.

(9) Mariani, E. and A. Ciferri, 1954- Sucrose-Ra ffinose- Water. CITS, Madrid. (10) Robinson, D. J. 1969- Sucrose Crystals from Dextran Containing Syrup. Ph.D. Thesis, U. Queensland. (11) Sarig, S. and J. W. Mullin, 1980. Size Reduction of Crystals in Slurries by the Use of Crystal Habit Modifiers. Ind. Eng. Chem. Proc. Des. Dev. 19 490. (12) Schenider, F., A. Emmerick, and O. C. Akyar, 1975. Occulusion of Non-Sucrose Substances During Crystalli- zation of Sucrose. Z. Zuckerind 23 (3) 113. (13) Smythe, B. M. 1971. Sucrose Crystal Growth. Sugar Tech. Rev., 1, 191.

(14) Sutherland, D. M. 1969- Crystallization-Dissolution Cycling of Sucrose Crystals. Chem. Eng. Sci., 24 192.

(15) VanHook, A. 1967. Sugar Crystallization. Compt. Rend. XIII Assembly CITS (Falsterbo) p. 30 CITS Tienen, Belgique. VOL. 21, NO. 2, OCTOBER 1981 135

(16) VanHook, A. 1969. Influence of Adsorbed Impurities in Growth and Habit of Sucrose Crystals. Vol. VIII Growth of Crystals, P. 38, Consultants Bureau, N.Y.

(17) VanHook, A. 1976. Sucrose Crystallized from Syrups Containing Raffinose. Proc. Res. Soc. , Japan Sugar Ref. Tech., 36, 74. (18) Vavrinecz, G. 1965- Atlas of Sugar Crystals. A. Bartens, Berlin. An Analysis of Root Damage During Piling *

Charles L. Peterson, Eldon R. Muller Mark C. Hall and Joseph C. Thompson

Received for Publication March 12, 1981

INTRODUCTION Few pieces of regularly used equipment have an average age as old as the unloading and piling equipment used to handle sugarbeets at the company owned piling grounds. Not. that age alone should imply anything derogatory, because updating, re- building and modernization are part of a continuing process within the agricultural maintenance divisions responsible for piler oper- ation. What age does imply is that major changes occur very slowly and that new piling concepts for purposes of reducing dam- age to the sugarbeets must be modifications to existing equipment if there is any hope to have the equipment on-line in a reasonable amount of time. PREVIOUS WORK The loss of recoverable sugar due to injury is well docu- mented in the literature.

Akeson and Stout (1) damaged sugarbeet rooLs with impacts of three and six feet upon a steel surface. They found that these impacts increased the respiration rate up to 23%, invert sugar accumulation up to 41%, sucrose loss up to 73%, and recoverable sugar loss up to 65%.

Cole (3) found that respiration rates were increased by as much as 26% by the level of mechanical damage during harvest and storage of the roots. He found that apparent sucrose was

*Approved as Paper No. 8131 of the Idaho Agricultural Ex- periment Station. The authors are Professor, Graduate Student, Scientific Aide and Scientific Aide, respectively, Department of Agricultural Engineering, University of Idaho, Moscow, Idaho 83843. VOL. 21, NO. 2, OCTOBER 1981 137

reduced by up to one percent, and invert sugars were increased by up to 22% as the number of mechanical operations to which the roots were subjected increased. Wyse and Peterson (9) reported that hand harvested roots with minimal injury had the lowest respiration rate and severely injured, machine washed beets off the pile had the highest (69% higher) respiration rate. After ten days the injured roots were respiring at a rate 43% higher than that of the hand harvested controls. Parks and Peterson (5) reported that respiration analysis showed the amount of damage caused by harvesting and piling the roots was comparable to dropping the roots two meters onto a solid surface. They reported in one study that damage reduced the percent of sucrose at 151 days' storage from 17.2% for beets with a bruise index of 10 compared to 15.6% for beets with a bruise index of 30. Precht et al. (6) reported that in storage studies, machine harvested samples always had sugar loss and dehydration levels above those of artificially injured samples and considerably higher than the non-injured samples. Backer et al. (2) reported that with the present estimate of loss of sugar due to respiration and microbial activity of 0.05 pounds per ton per day, a plant processing 5000 tons per day would lose 187,500 pounds of sugar per day. Precht (7) found in 150 days' storage that current machine harvesting techniques resulted in a sugar loss equivalent to 0.333 pounds per ton per day while beets that were not damaged lost 0.20 pounds per ton per day. Devletter and Von Gils (4) reported that changing "average" handling practices into "good" practices would save 3.6 kg sugar per metric ton of beets. They estimated an annual loss of sugar worth about $3.3 million in the Netherlands alone. Wyse (8) found that machine harvesting increased sucrose losses 135% above their hand harvested controls.

MATERIALS AND METHODS

This paper reports on studies conducted between 1975 and 138 JOURNAL OF THE A.S.S.B.T.

1979 in both Idaho and Washington. Data collected include bruise damage, respiration, sucrose loss, tare, and time and motion analyses. Bruise analysis has included comparing the bruise level of beets after they have gone across the piler with the level in the trucks delivering beets to the piler; by passing hand har- vested beets through the piler; and washing, weighing and mark- ing individual beets, passing them through the piler, recovering them, and then evaluating the damage level. The criterion for bruise index based on bruise depth was described by Parks and Peterson (5). They defined a slight dam- age as up to 10 mm, a moderate damage from 10 to 20 mm, and severe damage deeper than 20 mm. In all classifications, a damaged area was considered a single damage if it was less than one-quarter the face area of the rooL. If the damaged area was larger, the number of damages was the number of one-quarter face aras affected. A root was said to have a broken root tip if the diameter of the root at the point of breakage was 25 mm or more. A total damage score for each root, called a bruise index is given by the following equation: Bruise Index - Number of slights + (3 x number of moderates) + (8 x number of sev- eres) + (2 x number of broken root tips). Respiration measurements were made by the USDA respiration lab as reported by Wyse (8) and the research laboratory of U & I, Inc. Both of these methods monitor CCL respired by the beets. Samples used were collected at each step of the harvesting and handling operation. Tare studies compared tare samples taken from the current position following the cleaning screen and a lo- cation as the truck was unloaded. Current practice requires emptying the piler and leaving a gap following each truck. Con- sequently, each truck empties into an empty hopper resulting in considerable damage to the beets. For these studies a grab sam- ple technique was used to obtain the samples at the truck and the existing tare bucket system for the samples following the VOL. 21, NO. 2, OCTOBER 1981 139

cleaning screen. Pilers were selected for evaluation where dump trucks were being used to collect the tare dirt so that a weight of tare dirt removed between the two sample collecting points was available. All of the tare samples were evaluated by the re- spective sugar company tare laboratories. To determine the time lost as a result of the typical start- stop procedure of piler operation time and motion studies were conducted. The studies recorded all idle time of the piler. No attempt was made to estimate the portion of the time the piler was carrying less than a full load of sugar beets such as would happen at the beginning or end of each load.

RESULTS AND DISCUSSION Evaluation of sugarbeet piling equipment has included a number of different aspects over several years. Data discussed here includes sugarbeet damage measured by both respiration analysis and bruise index, and analysis of the potential for mov- ing the tare sampling location, and time and motion studies of the lost time at the piler. Sugarbeet Damage Various sampling techniques have been used to determine the damage levels inflicted by the piler. Generally beets that have been lifted with conventional equipment already have high damage levels when delivered to the piler. The increase in dam- age caused by the piler is then difficult to measure. Therefore in several studies, hand-harvested sugarbeets were introduced into the piler hopper with the regular flow of beets. In these instances damage levels about two-thirds of those occurring in harvesting were observed.

The first evaluations of piler damage, made in connection with harvester studies, included both point-to-point studies which monitored the damage from field to pile and comparison studies which monitored differences between harvesters and the piler. Fig. 1 gives an example of typical point-to-point data for one cooperator. Figs. 2 and 3 are examples of the injury levels typical of the comparison experiments. Six different point-to-point studies each with a different grower and four different piling 140 JOURNAL OF THE A.S.S.B.T.

ground studies were included in the original experiment. The data shown are typical of the other experiments.

Figure 1. - Bruise index treatment means tor an operation using a tank I ype har­ vester, Harvesting and Piling Point-to-Point Study 1975. The aster­ isk indicates Duncan's New Mulr. i -Range Test, Isd (.0 5) = 3.6.

Figure 2. - Cedars area, bruise index treatment means, Harvester Study 1976. The asterisk indicates Duncan's New Multi- Range Test lsd( .05)=, 3.1.

Figure 3. - Bruise Index and percent, tare for six harvesters and the sugarloaf piler, 1976 Harvester injury study. The asterisk indicates Duncan's New Multi-Range Test, 1sd (.05) = 5.16. VOL. 21, NO. 2, OCTOBER 1981 141

During the latter part of the 1975 harvesting season, an experiment was performed to evaluate the effect of the piler on uninjured roots- Hand-dug roots of average size and quality were selected. They were washed and their tops were removed with a tare machine. They were then painted fluorescent red so they could be easily seen in the pile and numbered with an indelible pencil so a record of weight and damage for each root could be made.

A weight loss was calculated for each root run through the piler. Out of the 24 roots recovered, 18 lost weight. The data were analyzed statistically using a paired "t" test. These roots were also visually graded for bruise damage. A bruise index of 15.9 was measured. No correlation could be found between weight loss and damage level. There was, however, a correlation between weight loss and broken root tips. Of the 24 roots in this study, 10 (42%) had broken root tips. Broken root tips were the major contributor to weight loss in piling the undamaged roots. In October 1976, studies were conducted at the Cedars and Sugarloaf piling grounds near Twin Falls, Idaho, to assess piler damage on sugarbeets. Hand-dug beets were washed, crowned with a tare machine, and painted for identification. Three treatments were identified: beets conveyed through an empty piler, beets introduced into the piler hopper during normal piling, and beets added to the lop of the piler flow. All samples in this study were given a bruise index score. Based on this study, once the roots were in the piler hop- per, it appeared that visible damage was the same for a loaded or partially loaded piler. Damage was the same for roots on the bottom as well as on the top of the hopper (see Table 1).

Damage levels for the treatments in this study were low corn- pared to similar treatments in the storage studies. This study was conducted on a warm fall day. Since the roots had been dug the day before, they were warm when run through the piler which probably caused the bruise index to be lower than normal.

In November of 1976, sugarbeet samples were taken from the Winchester piler near Quincy, Washington. Samples were taken JOURNAL OF THE A.S.S.B.T.

Table 1. Number of Roots Recovered, Bruise index Score, and Standard Deviation Shown for Each Treatment and Location.

Number Bruise cf Index Treatment Roots Mean S Locat ion: Cedars 3.81 4.91 #1. 58 3.90 #2 38 4.50 #3 48 2.54 3.52

Locat ton: Sugarloaf 6.79 #1 64 4.98 #2 61 3.69 5.52 #3 59 5.29 6.83

Average Mean Score 4.13

Location #1 - Beets conveyed through an empty piler Location #2 - Beets introduced into a piler during norma] piling Location #3 - Beets added to the top of piler flow

from the top of a truck, from four locations within the piler, and off the piler for each of three truck loads. Bruise index and per- cent tare were computed for each sample. In this study, the amount of increased damage through the piler was not statistically significant. Damage levels of samples from off the top of a truck were already high, so assessment of further damage was difficult. The analysis of percent tare showed that with one harvester beets were significantly reduced in tare by running them through the piler. The beets from the other harvester, however, were cleaner than those off the pile. This suggests that cleaning is sometimes excessive in the harvesting-piling operation. Two studies in 1976, one at the Minidoka piling ground in Idaho (Fig. 4) and the other at the Moses Lake, Washington piling ground (Fig. 5) demonstrated the damage levels which could be expected from the piler when injury free beets were delivered to the piling grounds. Both studies used hand-harvested beets which were then passed through the piler with no other handling as one of the treatments. In both cases the piler alone caused approx- imately two-thirds the damage levels measured in beets which had been both mechanically harvested and piled. Fig. 6 shows the sucrose content after 151 days versus bruise index obtained from VOL. 21, NO. 2, OCTOBER 1981 143

a storage study using the Idaho treatments.

Figure. 4. - Bruise index treatment means, South Idaho Storage Study 1976. The asterisk indicates Duncan's New Multi-Range Test, lsd (.05) -- 5.6. The column for the top truck lifter was improperly harvested.

Figure 5. - Bruise index treat- means, Moses Lake Storage Study 1976. The asterisk in- dicates Duncan's New Multi-Range Test, lsd (.05) - 5.2.

Figure 6. - Regression of the mean values of percentage of sucrose at 151 days corrected to initial weight and bruise index, South Idaho Storage Study 1976. 144 JOURNAL OF THE A.S.S.B.T.

In the fall of 1977, sugarbeet samples were collected in south Idaho and the Columbia Basin to determine the bruise and tare differences existing between harvesters, points within har- vesters, and pilers. Six truckloads were sampled at the Mini-Cassia piling ground at Paul, Idaho. Harvester type was recorded for each load. Beets were taken from the top of each truck before unload- ing. The load was then dumped, run through the piler, and sampled again off the end of the boom. Additional samples were taken from the face of the pile. Eight truck loads were sampled at the Utah-Idaho factory super piler in Moses lake, Washington. Harvester type was re- corded for each load. beets were taken from the top of each load and from the face of the pile. Samples were also taken from ad­ jacent piles. The pile and a truck were sampled at the Beatrice piling ground near Cunningham, Washington. Beets were taken from the top of trucks at the K2H piling ground near Eureka, Washington. Samples were also taken from the pile face. All samples were visually graded and bruises were categor- ized giving a bruise index score. Each sample was also weighed, washed and reweighed for tare determination. The data for bruise index and tare for the study at Mini-Cassia are shown as Fig. 7. In general, damage was increased and tare reduced in passing the beets through the piler. These data are typical for the other similar studies.

Figure 7. - Percent tare and bruise index showing comparisons between truck and pile at the Mini-Cassia piling ground in 1977. VOL. 21, NO. 2, OCTOBER 1981

Respiration Studies In 1975, a respiration study was conducted cooperatively with the LSDA Laboratory at Logan, Utah. Treatments included artificially damaged beets, mechanically harvested and handled beets and both topped and untopped checks. Severely damaged beets respired at a level 69% above the topped check (Fig. 8).

Figure 8- - Respiration rates of artificially damaged and machine harvest damaged sugarbeets.

In October 1976, a sugarbeet respiration study was conducted at U & 1, Inc. in Moses Lake, Washington. two of the eight treat­ ments used in this study were run through a piler, while others were given various levels of damage. All samples were placed in respiration chambers for 90 days, where CCu content was monitored. Fig. 9 shows that CO„ content varies through the storage period, but generally that increased levels of damage give higher

Figure 9. - 1976 respiration study comparing hand harvested, hand har- vested and machine piled, and machine harvested and piled roots. 146 JOURNAL OF THE A.S.S.B.T.

respiration rates. Fig. 10 shows the mean respiration rates for all treatments between day 54 and day 68. The respiration rate of hand-harvested beets passed through the piler was significantly higher than the undamaged check but not lower than the machine- harvested beets passed over the piler. Fig. U shows a linearly

increasing relationship between CO2 content and bruise index.

Figure 10. -Mean respiration rates for treatments. Days 54 to 68. Moses Lake Respiration Study 1976. The asterisk indicates Duncan's New Multi-Range Test, 1 sd (.05) = .71.

Figure 11. — Regression of mean respiration rates (day 54 to day 68) and bruise index, Moses Lake Res- piration Study 1976.

Piler Analysis In October and November 1977 and 1978 studies were con-

ducted on pilers near Minidoka, Idaho and the K2H farm near Eureka, Washington. After each truck started to unload, sugar- beets were sampled from the cross conveyor at the base of the piler, while a conventional sample was taken at the tare bucket VOL. 21, NO. 2, OCTOBER 1981 147

station. In the 1978 study, two and three samples were taken at each location to give an indication of tare sample variation. All grower truck weights and tare dirt truck weights were recorded. All samples were taken to their respective tare laboratories for conventional analysis. The results show that the cross conveyor sampling technique underestimated conventional tare and therefore the estimate of tons paid for exceeded the actual paid tonnage by 1.75 to 4.5 percent. Cross conveyor sampling procedures could likely be improved from the simple catch frame used in these rests. In 1977 and again in 1979, time and motion studies were run on eight different pilers in Idaho and Washington. Only busy piling stations were selected for this study. A special timing de- vice containing two stopwatches and a memory was used. These data (Table 2) show that, very large trucks unloading with similar gap times result in better piling efficiency, or less time loss. Piling stations that capture all tare dirt collectively also tend to minimize time loss between loads.

Table 2. Piler Analysis in 1977 and 1979.

Total Total Avg. Percent Piler Trucks Time (min) Gap (min) Time Loss A 54 60.92 0.21 11.77 B 12 33.65 0.17 4.78 C 4 5.21 1.19 * D 3 6.93 0.35 5.05 E 22 3 4.09 0.13 6.57 F 39 63.41 0.09 5.39 G 40 60.32 0.10 5.87 U 42 67.81 0.22 12.25

* insufficient, data The data show that time losses varied between pilers, ranging from 5 to 12 percent. Operator discretion and truck driver ability were cause for variation. CONCLUSIONS These studies show a significant increase in root damage as sugarbeets are piled with conventional equipment. Contributing to that damage are long drops including the drop from the truck into 148 JOURNAL OF THE A.S.S.B.T.

the hopper and from the cleaning screen past the tare bucket onto the final elevator and the cleaning screen of either grab rolls or rubber kicker wheels. The procedure for taking tare currently in use requires that the pilers be operated in a stop-and-go manner completely emptying the machine following each truckload of beets. Intermittent operation of the piler can contribute to lost time of as much as 12 percent and often four to five percent. Tare sampling procedures which obtain the sample prior to unloading the truck should be considered. Even an improvement of five percent in piler efficiency is comparable to one new piler for every 20 in operation or unloading one additional truck for every 20 presently unloaded. If this could accompany a reduction in damage levels even further savings could be realized. Reducing damage at the piler and increasing piler operating efficiency could be of benefit to both the grower and the factory. Additional research will focus on specific remedies for reducing in- jury levels. Improved management practices can reduce injury with a minimum of capital expense and should be given first consider- ation at each piling ground. ACKNOWLEDGMENTS

This project is funded jointly by the University of Idaho Agricultural Experiment Station (Project. 685) and the Beet Sugar Development Foundation (Project 52). LITERATURE CITED (1.) Akeson, W.R. and E.L. Stout. 1978. Effect of impact dam- age on sucrose loss in sugarbeets during storage. J. Am. Soc. Sugar Beet Tcchnol. 20(2): 107-173. (2) Backer, L.F., F.C. Vosper and S.E. Bichsel. 1979- Ventil- ation and freezing of sugarbeet storage piles. North Dakota Farm Research 36(4):7-ll.

(3) Cole, D.F. 1977- Effect of cultivar and mechanical damage on respiration and storability of sugarbeet roots. J. Am Soc. Sugar Beet Technol. 19 (3): 240-245.

(4) DeVletter, R. and W. Van Gils. 1976. Influence of the mechanical handling of sugarbeets on sugar yield in the factory. The Sugar J. January 1976, pp 8-13.

(5) Parks, D.L. and C.L. Peterson. 1979. Sugarbeet injury VOL. 21, NO. 2, OCTOBER 1981 149

within harvesting and handling equipment. Transactions of the ASAE. 226):1238-1244. (6) Precht, T.A., D.L. Parks and C.L. Peterson. 1976. Effect of injury on sugarbeet storability. ASAE Technical Paper No. 76-4063. Presented at the 1976 Annual Meeting of ASAE, Lincoln, Nebraska. (7) Precht, T.A. 1978. The effect of injury on sucrose recovery from stored sugarbeet.s. An unpublished M.S. Thesis, Uni- versity of Ldaho, Moscow, Idaho. (8) Wyse, R. 1978. Effect of harvest injury on the respiration rate and sucrose loss in Sugarbeet roots during storage, j. Am. Soc. Sugar Beet Technol. 20(2) : 193-202. (9) Wyse, R.E. and C.L. Peterson. 1979. Effect of injury on respiration rates of sugarbeet roots. ]. Am. Soc. Sugar Beet Technol. 20(3):269-280. Effect of Nitrapyrin on Uptake of Nitrogen by Sugarbeet from Labeled Ammonium Sulfate*

F. J. Hills, A. Abshahi, F. E. Broadbent and G. A. Peterson

Received for Publication May 19, 1981 INTRODUCTION Nitrification inhibitors offer the possibility of conserving fertilizer nitrogen through preventing losses from denitrification and leaching. The literature concerning nitrification inhibitors is extensive. Maynard and Lorenz (3) have prepared an indexed reference to studies dealing with horticultural and many agronomic crops. Studies involving the effect of nitrapyrin (2-chlro-6- ( trichloromethyl ) pyridine) on sugarbeet production were done by Swezey and Turner (4) and Hagemann and Meyer (1) on sandy loam and clay loam soils in the Imperial Valley of California. In these tests sugarbeet yields were increased by about 10 percent when nitrapyrin, at 0.5 percent of the N applied, was mixed with ammonium sulfate or applied with anhydrous ammonia and sidedressed on both sides of plant rows. The experiment reported here utilized labeled ammonium sulfate which allows the determination of nitrogen in the crop derived from the fertilizer and thus a precise estimation of the effect of nitrapyrin on the fate of fertilizer nitrogen. MATERIALS AND METHODS Sugarbeet (Beta vulgaris L.), cultivar "US H10", was planted 24 May 1978 on a Zamora loam soil (mixed, nonacid, thermic Mollic Haploxeralfs) . On 7 June, after emergence was complete and seedlings were in the cotyledon to two- leaf stage, 15N depleted ammonium sulfate was applied in solution at 100 lb N/acre through a tube welded behind

*A contribution from the Departments of Agronomy and Land, Air and Water Resources, University of California, Davis, CA 95616. The authors are Extension Agronomist, Graduate Student, Professor of Soil Microbiology, and Staff Research Associate, respectively. University of California, Davis. VOL.21, NO. 2, OCTOBER 1981 151

a thin fertilizer knife 3 to 4 inches deep and 9 inches on each side of rows spaced 30 inches apart. Nitrapyrin was also applied in solution through a second tube welded just behind the first at 0.5 lb/acre. Both solutions were applied

under pressure from separate N2 cylinders. Treatments were: fertilizer N alone, fertilizer N plus nitrapyrin, and a zero N control in which the sidedressing knives were kept in the soil. Plots were four rows wide and 52 feet long. The treatments were arranged in a double latin square design. Plants were irrigated in furrows between the rows at two-week intervals. The last irrigation before harvest was on 18 September. Petiole samples were collected from the center two rows of each plot at two-week intervals, one week after each irrigation. Nitrate plus ammonium was determined by semi micro-Kjeldahl after extraction of plant

material with calcium sulfate solution and reduction of NO3

to NH3 by MgO and Devardas' alloy. Fifty feet of the center two rows of each plot were harvested by hand on 12 October, 20 weeks after planting. Two samples of tops and two samples of roots, about 10 each, were taken from each plot to determine dry matter, N uptake, root tare, and root sucrose concentration. Total N was determined by the Kjeldahl procedure modified to include nitrate. Percent nitrogen-15 was determined by mass spectrometry after conversion of ammonium to nitrogen gas with lithium hypobromite. Percent N in plant samples

derived from fertilizer was calculated as {(Pu-Pf )/(Pu-F)}100,

where Pu and Pf are the atom percent 15N of unfertilized and fertilized plants, respectively and F is the atom percent

15N of the 15N depleted fertilizer. Postharvest soil samples were taken by compositing two one-inch diameter cores per plot in one foot increments to a depth of six feet. RESULTS AND DISCUSSION The first irrigation following fertilizer application was on 12 June. On 16 June, nine days after fertilization, 20 seedling tops were taken from each plot. At this time there were no significant differences in fresh or dry seedling weight due to fertilizer N. There was an indication, though 152 JOURNAL OF THE A.S.S.B.T.

not statistically significant, that nitrapyrin was already inhibiting the uptake of fertilizer N as plants with nitrapyrin averaged 8.1 percent N from the fertilizer but without nitra­ pyrin averaged 11.5 percent N from fertilizer. To assess the extent to which plants take up ammonium ion and the possible effect of nitrapyrin on this uptake,

NH4-N was determined with an ammonium electrode in petiole samples. On 3 July, four weeks after fertilization, the

concentrations of NH4-N in dry petioles of plants not fertilized, fertilized with N alone, and fertilized with N plus nitrapyrin were 145, 285, and 245 ppm, respectively (LSD, 5% = 43, CV = 14.8%) and on 17 July, two weeks later were 60, 78, and 65 ppm, respectively (LSD,5% = 11, CV =- 12.9%). Thus fertilized plants took up more ammonium but nitrapyrin appears to have reduced this uptake. Reasons for inhibition of

NH4 uptake by nitrapyrin are not readily apparent but could be due to toxicity to roots in the areas where fertilizer and nitrapyrin were banded, either by nitrapyrin itself or

by higher levels of NH4. Ulrich and Mostofa (5) have shown toxicity of high concentrations of ammonium ion to young

sugarbeets. After 17 July the concentrations of petiole NH4 were too low to evaluate. By 17 July, plants of the zero N plots began to show N deficiency symptoms and continued to appear smaller in top growth throughout the rest of the growing period. At no time, however, was there a visible difference in the growth or color of fertilized plants without and with nitrapyrin. Table 1 compares the treatments during the season as to concentrations of NO3+NH4 in recently matured petioles and gives the percentages of the concentrations derived from the fertilizer. Figure 1 shows concentrations of NO3+NH4 in petioles from fertilizer and soil, respectively. Nitrapyrin reduced the uptake of fertilizer N and to some extent soil N for at least eight weeks after fertilization. From 10 weeks on there were no significant differences in concentrations of NO3+NH4, but from 12 weeks on concentrations were slightly higher for plants with nitrapyrin.

Figure 1 also shows that fertilized plants took up VOL. 21, NO. 2, OCTOBER 1981 153

more soil N than unfertilized plants for eight weeks following fertilization. The increase could be due to more rapid ex­ tension of the fibrous roots of the fertilized plants and/or to increased mineralization of organic matter stimulated by the presence of fertilizer N. The fact that nitrapyrin caused some reduction in the uptake of soil N lends suport to the hypothesis that fertilization stimulates the mineralization of soil N as in the presence of nitrapyrin there probably was some reduction in the nitrification of the increased supply of soil NH4.

VOL. 21, NO. 2, OCTOBER 1981 155

Table 2 shows the effects of the treatments at harvest on fresh and dry wt yield, N uptake, and percent N from fertilizer. On average, root yield increased 20 percent with fertilizer N but there was no significant increase with nitrapyrin over fertilizer N alone. Fresh top yield, however, was significantly increased 0.9 tons/acre in response to nitrapyrin. Concomitantly, root sucrose concentration declined 0.3 percentage points and gross sugar yield was the same without and with the nitrification inhibitor. There were no significant differences in the percentage of fertilizer N in roots and tops due to nitrapyrin but percentages with nitrapyrin were slightly higher. From Table 2 it is calculated that. crop uptake of nitrogen was nine pounds/acre greater with than without nitrapyrin and that about four pounds of this difference came from the fertilizer and about five pounds from the soil.

Postharvest soil samples showed 10 and 12 lb fertilizer N/acre as NOo+NH/ to a depth of six feet without and with nitrapyrin, respectively. Total fertilizer N in crops and N in soil as NCU and NH4 accounted for 48 and 54 percent of the fertilizer N applied without and with nitrapyrin leaving 52 and 46 percent not accounted for. Data are not available to assess the fate of this N but subsequent research by Abshahi (unpublished) indicates that most of it may have been incorporated into soil organic matter.

From these results it does not appear that nitrapyrin at 0.5 percent of the applied N will result in saving much fertilizer or soil N for sugarbeets when soil conditions favor nitrification. In an earlier experiment (2) we determined that sugar- beets fertilized for maximum sugar yield contained 24 to 76 percent N from fertilizer and soil, respectively. In the present experiment it is estimated that sugarbeets without nitrapyrin derived 23 and 77 percent of their N from the fertilizer and soil respectively, in close agreement with the previous experiment.

VOL. 21, NO. 2, OCTOBER 1981 157

SUMMARY

A field experiment at Davis, California compared concen­ trations of fertilizer N in petioles throughout the season and fertilizer N uptake after 20 weeks from labeled ammonium sulfate at 100 pounds N/acre without and with nitrapyrin at 0.5 lb/acre. For at least six weeks fertilization resulted

in more NH4 in petioles but this was reduced slightly by nitrapyrin. Fertilization markedly increased concentrations

of NO3+NH4 in petioles from fertilizer and soil for about eight weeks. During this period nitrapyrin reduced the uptake of fertilizer and, to some extent, soil N. Sugarbeets responded markedly to nitrogen fertilization but plants without and with nitrapyrin showed no visible difference throughout the season. Sugarbeets with the inhibitor yielded 0.9 and 0.5 tons/acre more fresh tops and roots, respectivelly, root sucrose concentration was decreased 0.3 percentage points but dry matter and sucrose yields were little changed. Fertilizer recovery was 38 percent without nitrapyrin and 42 percent when the inhibitor was used. There were nine more pounds N/acre in plants with nitrapyrin compared to those without, four from the fertilizer and five from soil, indicating that fertilizer N might be reduced about 10 percent by using the inhibitor under the conditions of this experiment. Sugarbeets without nitrapyrin obtained 23 and 77 percent of their N from fertilizer and soil respectively compared to 24 and 76 percent for sugarbeets with nitrapyrin.

ACKNOWLEDGMENT This work was financed in part by the Dow Chemical Company and the California sugarbeet industry. Special thanks are due George Turner and Gary Stockdale of Dow Chemical for help in applying the materials.

LITERATURE CITED

(1) Hagemann, R. W. and R. D. Meyer. 1980. nitrogen stabilizer gives mixed results. California Agri- culure, 34(5):14-15. (2) Hills, F. J., F. E. Broadbent and M. Fried. 1978. Timing and rate of fertilizer nitrogen for sugarbeets 158 JOURNAL OF THE A.S.S.B.T.

related to nitrogen uptake and pollution potential. J. Environ. Qual. 7:368-372. (3) Maynard, D. N. and O. A. Lorenz. 1978. Controlled release fertilizer and nitrification inhibitors for horti­ cultural crops, an index reference list. Vegetable Crops Series 196, Dept. of Vegetable Crops, University of California, Davis. (4) Swezey, A. W. and G. O. Turner. 1962. Crop experi­ ments on the effect of 2-chloro-6-(trichloromethyl) pyridine for the control of nitrification of ammonium and urea fertilizer. Agron. J. 54:532-535- (5) Ulrich, A. and A. E. Mostafa. 1980. Ammonium and nitrate as sources of nitrogen for sugarbeets. j. Am. Soc. Sugar Beet Technol. 20:553-570. Effects of Lime on the Chemistry of Sugarbeet Tissue

W. M. Camirand, J. M. Randall, E. M. Zaragosa and H. Neuman *

Received for Publication May 25, 1981 INTRODUCTION

Pretreatment of sugarbeet tissue with lime has been known to the industry for many years. In 1905 Weinrich proposed processing ground beets (21), and in 1908 and 1910 he patented processes involving the pressing of brei or chips which had been limed and then neutralized (22, 23). In 1956 Borghi described the Bonelli process for pressing juice from ground beets as an alternative to diffusion (4), and results of extensive tests on the process were later published (2, 3). In 1956 Loof and Pohl suggested the diffusion of cossettes in dilute lime water (11). In 1959 Susie proposed diffusion of cossettes which had been treated with a mixture of lime and sugar (16). In 1965 Goodban and McCready pro­ posed that cossettes be treated with powdered lime followed by normal diffusion (10), and Bobrovnik et al. studied this method further (1).

Degtyar (7) reported that the mechanical properties of cossettes cut from stale beets could be improved by addition of lime to diffusion water, whereas in Hungary 20Be lime so­ lution is occasionally added to the cutting machine drum for this purpose (18). To the authors knowledge there has been no sustained commerical application of any of the above techniques, aside from the occasional lime treatment of rotten and stale beets. Recent renewed interest in liming before extraction stems from the desire to reduce energy consumption in this industry. It has been estimated that the energy consumed per dollar

*The authors are Research Chemist, Research Chemical Engineer, Chemist and Research Chemist, respectively. U.S. Department of Agriculture, Berkeley, California 94710. 160 JOURNAL OF THE A.S.S.B.T.

value of product (87,000 Btu, 1973 prices) is greater than for any other food product industry (17). Of the over 2.3 X 10 Btu required to process one ton of beets approximately 25% is for pulp drying, 50% for thin juice concentration, 5% for lime production and 5% for heating the juices. Liming of fresh beet tissue holds the promise of reducing energy consumption in several of these operations. Potential advantages of beet liming are mostly a conse­ quence of the reactions of calcium hydroxide with the pectic substances that hold the cells together and make up as much as 30% of the water insoluble portion of the beet. In the standard extraction process, pectin polymer degrades and peptizes, entering the sugar juice along with other colloidal material from the cells. Subsequently, these impurities must be removed from the diffusion juice in liming, carbonation, settling and filtratation operations. When calcium hydroxide is added directly to the fresh beet tissue at 40°C or lower, deesterification of the pectin predominates over degradation; calcium crosslinks carboxyl groups to form a firm insoluble calcium pectate (10). Calcium crosslinked pectin produces a pulp that is firmer than conventional pulp. As a conse­ quence, the pulp may dewater mechanically to a greater de­ gree than conventional pulp, reducing the energy required to fully dry the pulp in rotary kiln dryers. The pulp solids could be significantly increased since pectin crosslinking may prevent pectin losses to the sugar juice. Also, ex­ traction temperatures may be lowered, since the beet cells will be denatured, and the high pH prevents fermentation at lower temperatures.

In sugarbeet pectin, about 50% of the carboxyl groups and about 30% of the hydroxyl groups in positions 2 and 3 are acetylated. Four reactions may occur when pectin is treated with calcium hydroxide: deacetylation producing ace­ tate as a by-product; ester hydrolysis or demethylation pro­ ducing methanol; calcium crosslinking of the free carboxyl groups and polymer degradation by glycosidic bond cleavage (Figure 1). At low temperatures the predominant reactions are the demethylation, deacetylation and crosslinking reactions. VOL. 21, NO. 2, OCTOBER 1981 161

At high temperatures glycosidic bonds adjacent to esterified carboxyl groups are also broken (Rx No. 4), greatly re­ ducing the mechanical strength of the beet tissue. Since the glycosidic bond is broken only when adjacent to the esteri­ fied carboxyl group, cold demethylation protects the pectin from subsequent hot alkaline degradation. Deacetylation, on the other hand, may be disadvantageous. Schweiger (15) has shown that solutions of acetyl pectates do not form gels or precipitates with calcium ion when the acetylation of hy- droxyl groups (positions 2 and 3) is above 55%; however, gels and precipitates will readily form when the degree of acetylation is below this amount. Schweiger suggests that hydroxyl groups are involved in calcium bonding along with the carboxyl groups, and he further suggests that they have to be in vicinal pairs belonging to the same unit (note that, vicinal pairs occur only when less than 50% of the hydroxyl groups of the polygalacturonic acid are acetylated). Since sugarbeet pectin has no more than 30% acetylation, leaving sufficient vicinal pairs for gel formation, further deacety­ lation may have little advantge in terms of pulp handling characteristics and only add an impurity, calcium acetate, to the subsequently pressed and/or extracted sugar juice. Some deacetylation will be unavoidable during the cold deme­ thylation, but fortunately, calcium acetate is not a particu- 162 JOURNAL OF THE A.S.S.B.T.

larly deleterious impurity, having a negative melassigenic coefficient of -0.55 (13). This paper presents the results of experiments to de­ termine the effect of variations in the conditions of liming sugarbeet tissue on the chemistry of the pectin-lime reactions, the yield of extraction pulp, and the extraction rates. Subse­ quent papers will be concerned with the effects of liming of sugarbeet tissue on diffusion juice, on thin juice purity and composition, and on pulp processing characteristics.

MATERIALS AND METHODS

Saponification Rates The relative rates of demethylation and deacetylation of limed beet tissue were obtained by mesuring the residual ester and acetyl content of pulp after reaction with lime. Beets were washed in a rotary washer, trimmed, and dipped for about 3 minutes in a cold solution of chlorine (1000 ppm). The beets were then dried by brief contact with 50°C dry air and stored at 1°C for no more than 4 days before cutting and liming. Cossettes were cut in a pilot plant cossette cutter designed and constructed at this laboratory. Julienne strips were produced with special attachments to an Urschel dicer. These strips had an 1/8" square cross section. Cos­ settes and julienne strips were limed by mixing with dry reagent grade Ca(OH)2 in a double cone mixer after thermal equilibrium had been reached. The lime level corresponded to 1% CaO, and at timed intervals 200 gram samples were re­ moved from the mixer and placed immediately into acidified

acetone (750 ml. acetone, 200 ml. H20, 50 ml. Con. HC1). These cossette slurries were then frozen at -34°C, and the acetyl and methoxyl contents of the marc were later measured by the method of McComb and McCready (12), as revised by Gee et al. (9). Fresh unlimed control samples were also frozen in the acidified acetone mixture, and some were set aside for determination of cossette factor and Silin number.

Yield of Pulp Solids Cossettes that had been treated either with dry Ca(OH)2 (at 0.5% and 1.0% as CaO on beets) or in thin juice lime VOL. 21, NO. 2, OCTOBER 1981 163 slurry (2.0 and 4.0%, calculated as CaO) were carefully weighed, placed in 20-mesh wire baskets, and suspended in 70° and 75 running water. After extraction for a given time period, pulp was removed from the running water, dried in an oven at 100 C for 16 hours and weighed. the 20-mesh wire baskets were fine enough so that virtually no beet tissue could escape. The dry pulp sugar content was determined by extracting the sugar in ethanol by the standard AOAC method followed by colorimetric analysis of the total sugar as recommended by Dubois et al. (8). Calcium analysis was carried out on the dry pulp by atomic absorption using a Perkin Elmer 303 AA spectrophotometer. Sample preparation was by a modified dry ashing method of Chapman and Pratt (6) . Final determination of the solids was accomplished by subtracting the sugar and calcium content from the total dry solids to determine the weight of the insoluble solids not influ­ enced by unextracted sugar or the calcium added in the liming process. Ratios of corrected solids to corrected control solids were then calculated.

Sugar Extraction Rates Dry lime treated cossettes, slurry treated cossettes and control cossettes were extracted in 20-mesh wire baskets in 75°C and 80°C running water. Sample baskets were removed from the water at 1, 2, 4, 6, 8, and 10 minute intervals.

Dry lime treatment was by mixing of Ca(OH)2 (at 0.5% or 1.0% as CaO) with the cossettes for 5 minutes in a double cone mixer, followed by 10 minutes of standing before ex­ traction at 80 C. Slurry treatment was achieved by dipping cossettes into 2% and 4% lime slurrys (as CaO on wt/wt basis) of thin juice (14Bx) for five minutes and draining for 10 minutes. These slurry treated cossettes were extracted in the same fashion as the dry lime treated cossettes In 75°C running water. Extracted cossettes were dried and sugar determined by the same methods used in the pulp yield experiments. Lime Consumption To determine the lime consumption for slurry treatment, 164 JOURNAL OF THE A.S.S.B.T.

1 liter Ca(OH)2 per liter of thin juice were used. Three suc­ cessive 200 cm batches of cossettes were dipped for 10 minutes each. Total calcium and total alkalinity were measured titri- metricaily using 1/28 N IIC1 and 1/28 N EDTA both before and after cossette treatment.

RESULTS AND DISCUSSION The results of the demethyla tion and deacetylation studies on beet strips limed at 1% for various time periods and temperatures are shown in Figures 2 through 9. All duplicate analyses were repeatable with 4%. Cossettes had a Silin No. of about 12 and a cossette factor of 25. Julienne strips had a Silin No. of 6.4 and a cossette factor of 290.

Saponification of Cossettes For cossettes, demcthylation and deacetylation rates

Figure 3. Saponification of beet pectin. Degree of deme- thlation and deaceth1 ation v.s. time. Cossettes treated at 18°C with dry Ca(0H)2 1.3% on beets (1% as CaO). VOL. 21, NO. 2, OCTOBER 1981 165

were similar at 5o and 18o C, over the first 50 minutes, al­ though demethylation progressed somewhat more rapidly at 18°C than at 5°C. Figure 4 shows much more rapid deacetyla- tion at 37o C than at the lower temperatures. At 5o C and 18o , deacetylation never became more than about 60% complete, but at 37°C deacetylation rose to almost 80% completion.

Figure 4. Saponification of beet pectin. Degree of demethylation and deacetyla­ tion v.s. time. Cossettes treated at.. 36°C with dry Ca(0H)2 1.3% on beets (1% as CaO).

Saponification of Julienne Strips From Figures 5 and 6 it can been seen that, lime did not penetrate into the julienne strips nearly as well as it did into the cossettes. Even after 50 minutes reaction time total

demethylation was less than 50%. A comparison of the surface of cossettes with julienne strips would suggest that the smaller degree of penetration of lime into the julienne strips is due not only to their greater thickness but also to the "cleaner cut" obtained in the Ursnel compared to the feathered and cracked surfaces obtained in a cossette cutter. The much lower demethylation rates for julienne strips would be in a- greement with the observation made by Goodban and McCready that lime penetration into a cossette is more rapid than would be predicted from results with microtome-cut pieces (10). Use of julienne strips was discontinued as soon as cossettes were available, for much of the advantages of liming beet tissue is lost if the lime or sugar cannot diffuse through the strip in a reasonable time. 166 JOURNAL OF THE A.S.S.B.T.

Figure 5. Saponification of beet pectin. Degree of demethylation and deacetyla— lion v.s. time. Julienne cuts treated at 6°C with

dry Ca(OH)2 1.3% on beets (1 .0% as CaO).

Figure 6. Saponification of beet pectin. Degree of demethylation and deacetyla— tion v.s. time. Julienne cuts treated at 35°C with dry Ca(OH)2 1.3% on beets (1% as CaO).

Rate of Demethylation vs. Deacetylation Since demethylation is a positive reaction promoting Ca+2 crosslinking and inhibiting pectin degradation while deacetyla- tion is probably disadvantageous, consuming lime and pro­ ducing acetate ion impurity, the ratio between deacetylation and demethylation could provide valuable insight into optimum processing conditions. In Figure 7, the deacetylation to deme­ thylation ratios are plotted for the cossette treatment at 1% lime addition (CaO) for 5, 18, and 37°C. At 18°C and equili­ bration times under 20 minutes this ratio is significantly lower than at 5° or 37°. Figure 3 shows that about 90% of maximum demethylation was achieved in about 10 minutes. It might be concluded, then, that optimum temperature for the addition of dry lime would be around 20° with a 10 to 15 minute re­ action time before diffusion. VOL. 21, NO. 2, OCTOBER 1981 167

Figure 7. Deacetylation to demethylation ratios for sugar beet cossettes limed at 1.3% Ca(0H)2 on beets (1% as CaO) at 5°C, 18°C and 37°C.

Effects of Temperature on Saponification of Cossettes In Figure 8 the curves of Figures 2, 3 and 4 are super­ imposed onto one graph without the data points. This shows that the demethylation and deacetylation curves are not stacked according to increasing temperature as one might expect; there is much crossover in the curves. However, looking at total deesterification (i.e. demethylation and deacetylation) for these three temperatures the curves are stacked according to temper­ ature (Figure 9). Thus, after 10 minutes equilibration the % demethylation is greater at 18° than at 37°, yet total deesteri­ fication is always greater the higher the temperature. All this would seem to indicate that demethylation and deacety­ lation are not independent of one another, and it would not seem unreasonable to expect Ca+2 crosslinking of carboxyl groups to inhibit both demethylation and deacetylation through steric hindrance or simply retardation of the rates of diffusion of calcium hydroxide into the cossette tissue.

Figure 8. Superimposition of the curves of figures 2, 3, and 4 without data points. 168 JOURNAL OF THE A.S.S.B.T.

Figure 9. Total deesterifi- cation of beet pectin in 5°C, 18°C and 37°C cossette runs, where methoxyl and acetyl groups are added together to determine degree of total esterification.

Lime Consumption Pectin has been reported by Vukov to comprise 16.3 +_ 5.9% of sugarbeet marc for normal European beets (19). However, the beets used in these experiments contained a- round 25% pectin in the marc, with about 0.44 methyl groups per pectin unit and about 0.8 acetyl groups per pectin unit on the untreated pulp. If it is assumed that the marc com­ prises about 5% of the beet then the pectin comprises about 1.25% of the beet. The average unit molecular weight of sugarbeet pectin in these beets was 176.12 + 0.8 X 42 + 0.44 X 14, or 215.88, where 176.12 is the formula weight of the anhydrogalacturonic acid unit. Only one calcium equivalent per pectin unit is required to totally demethylate and cross­ link the pectin. If total deacetylalion is included, then 1.8 equivalents of CaO is required per pectin unit. If it is as­ sumed that the original beet is 1.25% pectin, then full deme- thylation and deacetylation will require 0.29% CaO on the cossettes. Total acid content of sugarbeet press juice for a normal year, as reported by Wallenstein (20), is 60 meq/kg of pulp. Since the press juice does not contain much petinic acid, Wallenstein's value corresponds to an additional lime demand of 0.168% for a total lime consumption of 0.460% on the cos­ settes. When cossettes are limed by treatment in a thin juice lime slurry the lime consumed is the sum of that lime which reacts with the cossettes and that which is carried over on VOL. 21, NO. 2, OCTOBER 1981 169

removal of the cossettes from lime slurry reaction vessel. The average results for these experiments are shown in Table 1.

Table 1. Calcium and alkalinity changes of one liter of thin juice-lime slurry on treatment of 2.00 gms. of cos­ settes (Expressed as % CaO).

Alkalinitya Calciuma Initial slurry 1.88 1.90 Final slurry 1.50 1.58 Consumed* 0.63 0.53 (% on Cossettes)

a Average of three experiments.

The consumption of alkalinity at 0.63% Ca (CaO) was 37% greater than theoretical. In addition, lime slurry was lost from the treatment vessel because of carryover of slurry with the cossettes. The average carryover volume was about 40 ml. per 200 gram batch. This represented about 0.75 grams of CaO per batch, or 0.38% on the cossettes, for a total lime use of about 1 .0% on the cossettes. Although this is about the same lime consumption as with dry liming, it could probably be reduced by using a less concentrated lime slurry or a series of progressively less concentrated thin juice lime slurries. Cossettes treatment with a thin juice lime slurry would be favored over dry liming because of the relative ease of operation, minimized cossette damage with cossette slurry mixing compared to dry lime mixing, potential for using avail­ able equipment. For example, some cells of an Oliver Morton or Robert battery could be easily converted to this use.

Yields of pulp solids Results presented in Tables 2 and 3 show that solids yields were increased by as much as 30%, although generally the increase was on the order of 10 to 20% in the dry Lime experiments and around 27% in the slurry liming experiments. Lime reaction times of up to 90 minutes did not seem to ap­ preciably change the value of the limed to unlimed solids ratio. Only treatment of cossettes at 37°C with 0.5% dry 170 JOURNAL OF THE A.S.S.B.T.

lime did not appreciably increase the solids yield in the pulp.

Table 2. Effect, of dry liming on residual pulp weight after ex­ traction at 70 C For one hour.

Beet Temp., Lime Level Equilibration Limed Solids* °C % Times (min.) Control Solids 4 0.5 40 1.16 4 1.0 20 1.30 4 1.0 45 1.15 20 1.0 20 1.11 20 1.0 40 1.11 3 7 0.5 20 1.04 37 0.5 40 1.06 3 7 1.0 15 1.17 3 7 1.0 30 1.12

*Dried at 110°C for 16 hours; sugar and calcium weights subtracted from total pulp weight.

Table 3. Effect of slurry liming* on residual pulp weight after extraction at 75°C for fifty minutes.

Slurry Lime Dip Time Total Equilibration Time Limed Solids Conc. %Ca0 Minutes Before Extraction (Min) Control Solids Ratio 4 3 15 1.27 4 10 15 1.27 4 3 30 1.29 2 3 30 1.28 2 3 15 1.26 2 10 15 1.24

*Slurries used were both 2 and 4 percent lime (as CaO) in 15 Brix dilluted thick juice, slurry and cossette temp, were 20°C. All samples run in duplicate. Sugar Extraction Rates Results shown in Figures 10 and 11 reveal a 25 to 50% increase in residual sugar in the pulp of the limed cossettes after 10 minutes of extraction, a result thai was not unex­ pected since calcium pectate membranes have been used in the past to retard sugar diffusion (5). Although this result would seem to indicate the need for more prolonged diffusion for limed cossettes, the greatly improved dewatering obtaina­ ble with limed pulp may serve to eliminate the disadvantage. Calculations made from data on the solids content of limed VOL. 21, NO. 2, OCTOBER 1981 171

Figure 10. Residual sugar in cossettes limed with dry Ca(0H)2 at 0.5% and 1.0% (calculated as CaO) plus control after extracting in 75° running water for up to 10 minutes.

press pulp and control press pulp (14), combined with the known increase in pulp solids brought about by liming, indi­ cate that more sugar could be removed from limed cossettes than from unlimed cossettes for the same extraction and pressing conditions, since more sugar-bearing press water could, be removed and returned to the process. Thus the slight increase in residual sugar in limed pulp would not produce less favorable extraction economics for this process.

Figure 11. Residual sugar in cossettes limed with 2% and 4% thin juice (14Bx) lime slurries [(added as Ca (0H)2, calculated as (CaO)] for five minutes and drained for 10 minutes, compared to untreated control. Ex­ traction was in 80o C running water for up to 10 minutes.

SUMMARY The addition of lime to sugarbeet tissue at. lower temper­ atures causes demethylation of the pectin in the cell walls of the beet tissue, allowing Ca 2+ to crosslink the pectin as 172 JOURNAL OF THE A.S.S.B.T.

a stable insoluble matrix. This permits alkaline diffusion with less disintegration of the pulp. High deacetylation rates and pectin degradation above 37°C could limit, process to lower temperatures. The retention of pectin in the pulp after lime treatment of beet tissue was improved, as was indicated by a 10 to 30% increase in solids in the pulp. Cossettes dipped in lime slurry gave the best overall pulp weight increase of about 27%. In a factory operation, the magnitude of the ratio of pulp solids per ton of beets should be an indicator of the releative amount of calcium pectate formation versus the amount of degradation, and should be a useful parameter of process control. Since beet pulp is worth about $100/ton as cattle feed, a 10 to 30% increase could represent a sub­ stantial economic advantage. Although extraction rates were significantly reduced by cossette liming, total sugar yield from cossettes should be improved over conventional processing due to the increase in press water yield for the same pressing conditions (14). A thinner cossette might also be advantageous. Sugar ex­ traction would be improved, and since hydrodynamic resistance would be less than for unlimed cossettes of the same size, the objections to smaller cossettes would not be applicable. Other forms of beet tissue could be used with various ex­ traction systems, but the cossette has a number of processing advantages.

ACKNOWLEDGMENTS This project was partially funded by the Department of Energy under Interagency Contract Number EM-78-1-01-5182. The authors wish to thank Gary McDonald for analytical work, Alex Hill for laboratory assistance, Spreckels Sugar Co., Woodland, California, for supplying the sugarbeets, and the Beet Sugar Development Foundation for loan of equipment and for its general support.

Reference to a company and/or product named by the Department is only for purposes of information and does not. imply approval or recommendation of the product to the exclusion of others which may also be suitable. VOL.21.NO. 2, OCTOBER 1981 173

LITERATURE CITED

(1) Bobrovnik, L. D., G. P. Voloshanenko and A. R. Sapronov. 1977. Effect of the liming of beet chips on juice quality. Sakh. Prom. (Moscow) 1:11-13. (2) Bonelli, A. 1955. Process of obtaining sugar by means of defecation with CaO carried out on beets after crushing and rolling them, thereby avioiding the hot diffusion process. Italian Patent No. 573,733. (3) Bonelli, A. 1959. Estrazione dello zucchero per de- faccasione operate direttamente sulle barbabietole. L'lndustria Saccarifera Italiani 52:399-411. (4) Borghi, M. 1946. 11 nuovo processo del dott. Bonelli per 1'estrazione dello zucchero dalle bietole. La Chimica e l'lndustria 28(11-12):177-184. (5) Camirand, W. M. et. al. 1968. Dehydration of Membrane Coated Foods by Osmosis. J. Sci. Food Agric. 19, 472-474, August. (6) Chapman, H. D. and P. F. Pratt. 1961. Methods of analysis for soils, plants, and waters. University of California. (7) Degtyar, M. Y. 1948. Diffusion of long-stored beets. Sakhar. Prom. 4:28-29. (8) Dubois, M., K. A. Gilles, J. K. Hamilton, P. A. Rebers and F. Smith. 1956. Colorimetric method for determina­ tion of sugars and related substances. Anal. Chem. 28(3):350. (9) Gee, M., E. A. McComb and R. M. McCready. 1958. A method for the characterization of pectic substances in some fruit and sugarbeet juices. Food Research 23:72-75. (10) Goodban, A. E. and R. M. McCready. 1965. Liming of sugarbeet cossettes. J. Am. Sugar Beet Technol. 13:564-572. (11) Loof, H. G. and W. Phol . 1956. Process for extracting sugarbeets, using weakly alkaline water. French Patent No. 1,129,771. (12) McComb, E. A. and R. M. McCready. 1957. Determina­ tion of acetyl in pectin and in acetylated carbohydrate polymers. Anal. Chem. 29:819. (13) McGinnis, R. A. 1971. Beet-sugar technology. Beet Sugar Development Foundation, Fort Collins, Colorado, Second Edition. Pg. 585, pg. 125. 174 JOURNAL OF THE A.S.S.B.T.

(14) Randall, J. M., W. Camirand, and E. M. Zaragosa. 1981. Effect of cossette liming on dewatering of beet pulp. J. Am. Soc. Sugar Beet Technol. (In press).

(15) Schweiger, R. G. 1946. Acetyl pectates and their re­ activity with polyvalent metal ions. J. Organic Chem. 29(10):2973-2978. (16) Susic, S. K. Studija o problemu alkine difuzije u in- dustriji secera . 1959. Prehranbena Industrija 13:1409- 1414.

(17) Unger, S. G. 1975. Engery utilization in the leading energy-consuming food processing industries. Food Technol. 29( 12)': 33-43. (18) Vukov, K. and M. Tegze, 1953. A meszezes hatasa a repaszeletra, (The Effect of Liming on Sugar-Beet Cossettes). Cukoripar 6:213-215. (19) Vukov, K. Physics and Chemistry of Sugar-Beet in Sugar Manufacture. 1977. Page 49. (20) Wallenstein, H. D., and K. Bohn, Sauren in Ruben and Saften (Acid in Beets and juice) Z. Zuckerind., 13, 125 (1963). (21) Weinrich, M. 1905. Process of treating sugarbeets. U.S. Patent No. 803,945. (22) Weinrich, M. 1908. Process of treating sugarbeets. U.S. Patent No. 881,641. (23) Weinrich, M. 1910. Process of treating sugarbeets. U.S. Patent No. 950,035. Fusarium Stalk Blight Resistance in Sugarbeet

J. S. McFarlane *

Received for Publication June 29, 1981

INTRODUCTION The Willamette Valley of Oregon is the principal sugarbeet seed production area of the United States. The crop is frequently damaged by a disease that causes wilting and eventual death of the seed plants. In severely affected fields over 50 percent of the plants show symptoms and seed yields are reduced. In 1973, Gross and Leach (1) identified the causal organism as Fusarium oxysporum Schlecht f. sp. betae (Stewart) Snyder and Hansen and called the disease stalk blight. In 1976, MacDonald, Leach, and McFarlane (2) reported a wide range in resistance among cultivars and parental lines that were grown in the Willamette Valley. The inbred cytoplasmic male-sterile lines 562HO and 563HO were found to be severely damaged by the disease. These lines are widely used by both the United States Department of Agriculture and commercial breeders in the production of hybrid seed for use in California and other parts of the United States. Beginning in 1976 a breeding program was started to improve the resistance of these parental lines. MATERIALS AND METHODS Field tests were made for 5 years (1976-80) in a Fusarium infested field near Salem, Oregon. Plantings were made in August or September of each year and the material was classified for Fusarium resistance the following August. Lines that were to be evaluated for resistance were replicated two to four times and material for selection was planted in blocks of several hundred plants. The grading system was

*Research Geneticist, U.S. Agricultural Research Station, Agricultural Research Service, U.S. Department of Agriculture, P.O. Box 5098, Salinas, CA 93915. 176 JOURNAL OF THE A.S.S.B.T.

similar to that developed by MacDonald, Leach, and McFarlane (2). Each entry was evaluated by examining 50 or more consecutive plants in a given plot. The plants were pulled and examined for vascular discoloration. The plants were assigned grades on a discontinuous scale—0 = no disease, 1 = slight vascular discoloration, 2 = moderate vascular discoloration, 3 = severe vascular discoloration, and 4 = com­ plete vascular discoloration with seed stalks dead (Fig. 1). A weighted mean or disease rating was computed based on the number of plants in each grade. Plants that, were graded 0 to 1 were considered resistant.

Figure 1. Standards used in classifying sugarbeet roots for resistance to Fusarium stalk blight. The roots are assigned grades on a discontinuous scale - 0 = no disease, 1 = slight vascular discoloration, 2 = moderate vascular discoloration, 3 - severe vascular discoloration, and 4 = complete vascular discoloration with seed stalks dead. Selections for resistance were made by examining the roots of all plants in a block planting of a given line and saving seeds from plants that graded either 0 to 1. Emphasis was placed on selections within self-fertile populations that produced primarily selfed seeds. Plants from any outcrosses that occurred could be readily identified by vigor or hypocotyl VOL. 21, NO. 2, OCTOBER 1981 177 color and then eliminated. Cytoplasmic male sterile (CMS) e- quivalent lines were produced by crossing the selected resistant lines with closely related CMS lines and then backcrossing to the resistant line. Information on inheritance of resistance and linkage was obtained by observing the segregation in F2 and backcross popu­

lations from F1 hybrids between resistant and susceptible parents. Mendelian and cytoplasmic male sterility were utilized to produce hybrids between self-fertile inbred lines.

RESULTS AND DISCUSSION Range in resistance: Tests made in each of 5 years showed that a wide range in resistance exists among sugarbeet breeding lines. Disease ratings for a representative group of inbreds (Table 1) included in a replicated 1979-80 test ranged from 0.01 to 3.97. The differences among inbreds were highly significant but variations among replications were also high. Disease ratings for the 564aa inbred ranged from 2.60 to 3.94 among four replications. These results indicated that Fusarium infestation occurred throughout the test field but that the level of infestation was variable. During the 5 year period, the

Table 1. Fusarium stalk blight resistance of sugarbeet inbreds replicated four times in a test at Salem, Oregon, 1979- 80. Ave.l/ %2/ Inbred Description Grade Resistant 554-14 S14 of 554 inbred 0.01 100 554 Bolting res. inbred 0.17 98 566 Fus. res. sel. 563 0.30 95 566HO 564 CMS x 566 1.63 59 563HO CMS of 563 inbred 2.49 32 564aa Mendelian male sterile 564 3.47 11 564HO CMS of 564 3.95 0 564 Bolting res. inbred 3.97 0 LSD (.05) 0.48

_1/ Rated on scale of 0 to 4 with 0 = no disease and 4 = dead plant. Grade is average for number of plants observed. 2/ Plants in grades 0 to 1 are considered to be resistant. 178 JOURNAL OF THE A.S.S.B.T.

tests were all. made in the same 10 acre-field but were moved from one area to another within the field. Each of the areas was infested with Fusarium but the level of infestion varied from one area to another (Table 2).

Table. 2. Variation in Fusarium stalk blight grades of sugarbeet breeding lines for the years 1976-80.

Breeding 1976 1977 1978 1979 1980 Line Grade 1/

554 — 0.09 0.08 0.08 0.17 5 54-14 0.04 — 0.10 0.09 0.01 564 3.86 3.60 3.62 — 3.97 564HO — 4.00 3.09 — 3.95

502H0 0.39 0.40 0.47 — 1.73 563 2.48 2.90 1.3 5 563H0 — 2.20 1.00 — 2.49 522 2.98 1.00 0.3 5 — 1.81

536-97 3.27 2.90 1.30 — 3.23 566 — — 0.20 0.25 0.30 C13 — 0.70 0.07 0.27 1.35 564H1 1.42 1.20 0.09 0.67 3.03 522H21 2.07 1.00 0.45 1.73 3.22

1/ Rated on scale of 0 to 4 with 0 = no disease and 4 = dead plant. Grade is average for number of plants observed.

Selection for resistance: The objective of the selection program was to develop a stalk-blight resistant monogerm inbred line and its CMS equivalent that were similar in performance to the parental lines 562 and 563. Two methods were used to meet this objective: (1) Crosses were made between the Men- delian male sterile segregates of 563 and a closely related multi- germ inbred with moderate resistance to stalk blight. Selections were then made in the F2 generation. (2) Differences in re­ sistance were observed among plants within 563 and other partially inbred lines. Selections were made directly from these inbreds.

The increase of the best segregate in a F2 population from a cross between 563aa and multigerm inbred 502 had VOL. 21, NO. 2, OCTOBER 1981 179

a disease rating of 0.76 (Table 3). Selection 566 made directly from the 563 inbred graded 0.30 compared with the grade of 1.57 for 563. A selection from the 536 inbred had a disease rating of 0.76 compared with the rating of 3.71 for 536. The 563 inbred used in this study was the third successive increase of a self-fertile line that had been selfed three generations. The 536 inbred was the fifth successive increase of another self-fertile line that had been selfed three generations. The results show that variation for Fusarium resistance still occurs in 563 and 536 and that substantial gains in resistance can be made through selection within partially inbred lines. The selection from 563 has been officially released by the U.S. Department of Agriculture and the Beet Sugar Development Foundation under the designation C566. The line was crossed to a closely related CMS in 1978 and the resulting hybrid (566HO) gave a disease rating of 1.63 (Table 3). The first backcross to C566 was made in 1980 and a second backcross accompanied by a selection for stalk-blight resistance will be made in 1981.

Table 3. Progress in selecting for Fusarium stalk blight resistance.

No . Ave . 1 / %2 / Line Description Plants Grade Resistant

566 Resistant selection of 563 622 0.30 95 563 S3 inbred 125 1.57 59 563HO Cytoplasmic male sterile 563 226 2.49 32 566HO 564H1 x 566 196 1.63 59 564H1 (502HO x 563) x 564 76 3.03 22 502HO Cytoplasmic male sterile 502 26 1.73 58 536-4 Resistant selection of 536 68 0.76 81 536 S3 inbred 34 3.71 6 505-32 Sel. from F2(563aa x 502) 37 0.76 86

1/ Rated on scale of 0 to 4 with 0 = no disease and 4 = dead plant. Grade is average for number of plants observed. 2/ Plants in grades 0 to 1 are considered to be resistant. 180 JOURNAL OF THE A.S.S.B.T.

Linkage studies: Many of the monogerm inbreds developed in the sugarbeet breeding program at Salinas, California, are susceptible to stalk blight whereas most of the multigerm inbreds tend to be resistant. or intermediate. I suspected that there might be a linkage between susceptibility and

the monogerm character. Segregating F2 and backcross populations from hybrids between monogerm and multigerm parents were observed for stalk-blight susceptibility (Table 4) . Each monogerm plant and each multigerm plant was graded. Average grades were computed for each multigerm and monogerm population. In four of the populations the stalk-blight grade level was slightly higher for the monogerm plants and in the fifth population the level was slightly higher for the multigerm plants. The differences in stalk blight resistance between paired multigerm and monogerm populations were not statistically significant. The results indicate no close linkage between the monogerm character and stalk-blight susceptibility.

Table 4. Comparison of the Fusarium stalk blight resistance of multigerm (MM, Mm) and monogerm (mm) sugarbeet plants in segregating populations.

No. Plts. Ave. Gradel/ Line Description M- mm M— mm

802 F2 (Sus. mm x Res. MM) 178 52 0.26 0.42 803 F2 (Sus. mm x Res. MM) 176 99 0.14 0.26 804 F2 (Sus. mm x Res. MM) 138 49 0.08 0.12 105 Sus. mm x (Sus. mm x Res. MM) 150 124 0.48 0.31 103 (Sus. mm x Res. MM) x Sus. mm 144 123 0.81 1.21 LSD (.05) NS

1/ Rated on scale of 0 to 4 with 0 = no disease and 4 = dead plant. Grade is average for number of plants observed. Inheritance of resistance: The wide range in stalk- blight resistance among breeding lines provided an opportunity to study the mode of inheritance. The highest levels of resistance and susceptibility were found in self-fertile inbred lines. To facilitate hybridization, Mendelian and cytoplasmic male sterile forms of the susceptible 564 inbred were produced and evaluated for stalk-blight resistance. The Mendelian VOL. 21, NO. 2, OCTOBER 1981 181

male sterile 564aa gave a stalk-blight grade of 3-47 with 12 percent resistant plants compared with a grade of 3.97 and 0 percent resistant plants for 564 (Table 5). Although 564aa has a high level of stalk-blight susceptibility, it is not homozygous for susceptibility and is not an ideal parent for use in inheritance studies. The CMS 564HO line has a stalk-blight grade of 3-95 with 0 percent resistant plants and is probably homozygous for susceptibility.

Table 5. Fusarium stalk blight resistance of sugarbeet hybrids and their inbred parents.

1/ Rated on scale of 0 to 4 with 0 •= no disease and 4 = dead plant. Grade is average for number of plants observed. 2/ Plants in grades 0 to 1 are considered to be resistant.

When 564aa and 564HO were crossed with the resistant 554 inbred, the F-^ progenies graded 0.14 and 0.30 with 97 percent and 93 percent resistant plants, respectively. These results indicated that resistance was dominant. Stalk-blight evaluation tests with V populations of crosses between susceptible and resistant parents showed a high ratio of re- sistant to susceptible segregates. The proportion of resistant

plants in the F2 populations was especially high (.99% and 96%) when the resistant 554-14 line was used as the male parent in crosses with the susceptible 563aa and 564aa lines. When

the F1 (564HO X 554) was backcrossed to the resistant 554 parent, the average grade was 0.18 with 97 percent resistant 182 JOURNAL OF THE A.S.S.B.T.

plants. When the F, (564aa x 554) was backcrossed to suscepti- ble 564aa, the grade was 0.41 with 92 percent resistant plants. No firm conclusions can be drawn regarding the mode

of inheritance. Both the F2 and backcross data indicate that more than one gene is involved. The lack of homozygosity in the 564aa parent, and variability in Fusarium distribution throughout the test field caused problems in correctly interpreting the data. Likewise, root and stalk symptoms are discontinuous and range from a complete lack of symptoms to dead plants. An accurate classification of resistant and susceptible plants was difficult. Additional work including the development of a homozygous susceptible Mendelian male sterile inbred is needed. Supplemental artificial field inoculation with Fusarium could be a useful means of reducing field variability. Even though the mode of inheritance is not fully understood, information obtained in these experiments will be a substantial aid in the planning and conduct of a breeding program. Resistance is definitely dominant and only one parent of a F1 hybrid needs to be resistant. Progress has been made in selecting resistant monogerm parental lines and their male-sterile equivalents but none of the selections are homozygous for all genes. The inheritance data suggest that further improvements may be possible through additional selection.

SUMMARY Sugarbeet seed crops grown in the Willamette Valley of Oregon are frequently severely damaged by stalk blight caused by Fusarium oxysporum f. sp. betae. A wide range in resistance occurs among breeding lines ranging from no injury to death of all plants. The partially inbred lines 562 and 563 that are extensively used as parents in commercial hybrid varieties are susceptible. A resistant selection was made from the 563 line. Resistance was found to be dominant. No close linkage was demonstrated between susceptibility to stalk blight and the monogerm character. Resistance is controlled by more than one gene. VOL. 21, NO. 2, OCTOBER 1981 183

ACKNOWLEDGMENT The author is indebted to S. C. Campbell and R. R. Reasoner of the West Coast Beet Seed Company for help with the agronomic work at Salem, Oregon. LITERATURE CITED (1) Gross, D. C. and L. D. Leach. 1973. Stalk blight of sugarbeet seed crop caused by Fusarium oxysporum f. sp. betae (Abstr.) Phytopathology 63:12l6. (2) MacDonald, J. D., L. D. Leach, and J. S. McFarlane. 1976. Susceptibility of sugarbeet lines to the stalk blight pathogen Fusarium oxysporum f. sp. betae. Plant Dis. Reptr. 60:192-196. Effects of Sugarbeet Sample Preparation and Handling on Sucrose, Nonsucroses and Purity Analyses *

R. J. Hecker and S. S. Martin

Received for Publication July 21, 1981

Sucrose recovery from sugarbeet (Beta. vulgaris L. ) is not only a function of sucrose concentration in the roots but also of the proportion of sucrose which can be crystallized from purified beet juice. The proportion of recoverable sucrose is affected by the quantity of soluble nonsucrose compounds in the roots relative to sucrose, but also it may be affected by a particular factory process. Several of the soluble nonsucrose compounds present in beets affect the solubility and rate of crystallization of sucrose. Hence, these compounds and other quality factors must be measurable or assessable in order to evaluate the quality of the beets and various processing juices. Quality assessment of the beets is a necessity in breeding, agronomic, storage and other research. Sampling and assessment for quality is done on a large scale in sugarbeet research, but not necessarily in a standard manner. Certain quality analyses such as laboratory thin juice purity, as developed by Brown and Serro (1) and modified by Carruthers and Oldfield (2), are relatively standard but not extensively used because of high cost. However, sample preparation and handling for purity and other assessments are not. standard. These techniques are largely dictated by local facilities, number of samples, and experience.

*This cooperative investigation of USDA, ARS, the Colorado State University Experiment Station, and the Beet Sugar Development foundation is published with the approval of the Director, Colorado State University Experiment Station, as Scientific Series Paper No. 2 6 89. The authors are Plant Geneticist and Plant Physiologist, respectively, USDA, Agricultural Research Service, Crops Research Laboratory, Colorado State University, Fort Collins, CO 80523. VOL. 21, NO. 2, OCTOBER 1981 185

Frequently, requirements of experiments necessitate preservation, transport, storage, and delayed analyses of beet juices or brei (finely subdivided root tissue) samples. Little published information exists to guide scientists in sample preparation and handling for these circumstances. We have conducted a series of integrated experiments over several years to compare a number of standard and practical methods of sugarbeet sample preparation and preservation for sucrose and quality analyses from beets or different genotypes grown under different levels of nitrogen fertility. This report summarizes these results and presents comparisons of various sample extraction and treatment effects on measurements of polarimetric and gas chromatographic sucrose, glucose, purity, and the important nonsucrose purity components.

MATERIALS AND METHODS All sugarbeet samples used in this study were from irrigated field experiments at Fort Collins, Colorado, planted in April and harvested in early October in several years. Polarimetric sucrose (sue) was measured in lead subacetate clarified solutions standard in the beet sugar industry (modified Sachs-Le Docte method). Gas chromatograph sucrose (GC sue) and glucose (glue) were measured as described by Maag and Sisler (6). Quantitative measurements were made as described by Maag et al. (5) for ash by conductance, for nitrate (NO3) by nitrate ion electrode, for chloride (CD by titration with silver, for sodium (Na) and potassium (K) by flame photometry, for amino-nitrogen (AMN) by ninhydrin reaction, and for total nitrogen (tot N) by a modified Kjeldahl technique (4). These determinations were all reported in mg/100 g sucrose in the respective extract or juice. The necessity of transporting and delaying sample analyses of sugarbeet juices sometimes requires the use of a preservative to prevent microbiological activity. We conducted an experiment to assess the effects on juice quality characters of phenylmercuric acetate (PMA) at 50 ppm as an extract preservative. The 165 samples in this experiment were purposely heterogeneous. Equal parts (w/w) of sugarbeet 186 JOURNAL OF THE A.S.S.B.T.

brei and boiling distilled water were blended 5 minutes and vacuum filtered. The samples were split (one of each pair receiving 50 ppm PMA) and analyzed for suc, refractive

dry substance (RDS), percent purity (pur), ash, NO3 Cl, Na, K, AMN, and tot N. The samples were analyzed immediately for pur, sue, and RDS, and refrigerated during the 2 days until the other analyses were completed. We did not study the efficacy of PMA as a preservative. Since sugarbeet brei samples sometimes need to be collected, then frozen for later sucrose analysis, we conducted experiments in 4 years comparing the quantities of sucrose in fresh and frozen brei from beets grown at different nitrogen (N) fertility levels. The experiments were grown at low optimum, or excess N fertility. Excess N was applied as a treatment to simulate the high N levels which sometimes occur in commercial production. Each brei sample was thoroughly mixed and split, one-half analyzed for sucrose immediately, and the other haif frozen immediately and stored frozen at -30°C for about 1 month. Another aspect of this study involved four experiments comparing different methods of juice extraction and subsequent handling. The following extraction methods were used for these experiments: 1:1 ext. - equal parts (w/w) sugarbeet brei and distilled water, blended 3 min. , vacuum filtered through Whatman No. 1 filter paper, and analyzed immediately. 1:1 ext. froz. = extracted as above, stored frozen at -30 °C. 1:1 froz. brei ext. = brei stored frozen at -30°C, extracted as above. Standard lab thin juice = pressed juice, limed, and stored frozen at -30°C. All frozen samples were thawed at 20 °C. The samples in these experiments were analyzed for the same characters as the PMA experiment. The beet samples were from four split plot and randomized complete block field experiments with four to ten replications. VOL. 21, NO. 2, OCTOBER 1981 187

Since the filtrate from sucrose analysis is always available, it is a practical sample from which to make other quality determinations. We conducted one experiment in which quantities of Na, K, and AMN were measured in 100 samples of fresh sucrose filtrate and identical subsamples stored 24hrs, or stored frozen and thawed at 4°C, 37°C, or by microwave. In another experiment, sucrose filtrate from fresh brei and frozen brei was compared with a frozen brei extract for concentration of Na, K, and AMN. The data from this experiment are reported in mg/100 ml, since each treatment was a subsample and conversion to mg/100 g sucrose would have confounded nonsucrose measure with any treatment effect on sucrose. All other nonsucrose data in this study are reported in mg/100 g sucrose. To assess storage methods of samples for purity analysis, we compared thin juice purities of limed pressed juice, (1) immediately after collection, (2) after 30 days of storage at -30 °C and then thawed at 20° C, (3) from brei frozen for 30 days at -30°C and then microwave thawed, and (4) after 14 days of storage at 4°C. Thoroughly mixed brei samples from 100 plots of beets in a randomized complete block experiment were divided into four subsamples for these treatments. Thin juice was prepared using the modified method of Carruthers and Oldfield (2). A comparison was made of sucrose determinations by polarimeter and gas chroma tograph in 10 cultivars in one randomized complete block field experiment with 10 replications. Glucose content was also determined in this experiment. All three measures were in percent of root fresh weight.

RESULTS AND DISCUSSION A comparison of sugarbeet brei extracts with and without 50 ppm PMA is shown in Table 1. From these 165 paired samples the only PMA effects were significantly lower ash and AMN contents. All other quality and nonsucrose characters were the same for the control and PMA treated samples. The differences for ash and AMN, although significant, were not sufficiently large tO Be of practical importance. 188 JOURNAL OF THE A.S.S.B.T.

It appears that PMA used as a sugarbeet juice preservative does not affect sucrose or quality determinations.

Table 1. Quality and nonsucrose characters in a 1:1 sugarbcet brei extract with and without 50 ppm phe nylmercuric acetate (PMA); 165 paired samples.

1:1 Extract mg/100 g sucrose Thin juice Ext Trmt . pur Sue RDS pur Ash NO3 CI NA K AMN Tot N No PMA 90. 5 6.9 8.42 81.1 49 6 7 1560 1800 1067 1200 3 30 1450 PMA 90. 4 6.9 8.39 81.0 4713* 1547 17 33 1070 1 200 3 1 7* 1490

*Significantly different (5%) from extracts with no PMA, using a pai red t test . A comparison of the sucrose content of paired samples of fresh brei and frozen brei from beets grown at low, optimum, or excess N fertility showed no significant differences in the four experiments shown in Table 2. The sucrose differences between low N and excess N were all significant, but there were no differences between fresh and frozen brei sucrose within these N treatments. Cormany (3) reported no differences between fresh and frozen brei sucrose in a test of 25 varieties. Hence, it appears that freezing the brei has no effect on the measurement of sucrose. This allows considerable flexibility in scheduling and transporting brei samples for sucrose analysis.

Table 2. Comparison of pol sucrose content (%) determined from tresh brei and frozen brei.

The various methods of juice extraction examined for quali- ty and for quantity of sucrose compounds are shown in Table 3. Of principal interest was the comparison of thin juice VOL. 21, NO. 2, OCTOBER 1981 189 purities of the extracts. All these thin juice purities were determined on the extracts by the method of Carruthers and Oldfield (2), with the appropriate quantity of lime being added just prior to purity analyses. The standard laboratory thin juice purities were determined on subsamples of pressed limed juice.

In the first experiment a comparison was made between 1:1 extract and 1:1 frozen brei extract, which was not different for thin juice purity, 90.1 and 90.0, respectively. Kefractive dry substance (RDS) and extract purity were determined in these same extracts. Their RDS's and extract purities were not different at 8.48 and 8.42, and 83.6 and 84.3, respectively.

In the second experiment the same two extracts were made and, additionally, one extract was stored frozen. The 1:1 extract, the 1:1 extract stored frozen, and the 1:1 frozen brei extract did not differ significantly with thin juice purities of 93.2, 93.4, and 93.0, respectively. However, standard laboratory thin juice purity of 95.8% was significantly different from the first three extraction methods. The leaded sucrose filtrate was included in the second and the third experiments only to provide some comparative data for the nonsucrose characteristics in the various extracts. In the third experiment only a 1:1 frozen brei extract was tested. This extraction method was both practical and convenient and, thus, of greatest interest. Again, in this experiment the thin juice purity of this extract was significantly lower than the standard laboratory thin juice purity, 95.7 and 96.3, respectively. However, in a fourth experiment there was no difference between the purities of the 1:1 frozen brei extract and the standard laboratory thin juice, 94.9 and 94.7, respectively. There- fore, in 2 years out of 3 the thin juice purity of 1:1 frozen brei extract was significantly lower than that of standard laboratory thin juice prepared from limed pressed juice. Apparently there is a treatment by year interaction, implying 190 JOURNAL OF THE A.S.S.B.T.

that purities of different extracts should not be used over years for comparative purposes. However, in these experiments the associated variances were not different. Therefore, consistent use of one or the other extract for thin juice purity determination should be equally acceptable for research purposes. GC sucrose was measured only in the extracts of the second experiment (Table 3). The 1:1 frozen brei extract had significantly higher pol and GC sucrose than the other extracts. However, this was not reflected in the thin juice purity because of a commensurately higher RDS. The nonsucrose compounds in the various extracts (Table 3) did not differ in the first experiment. Among the extracts in the second experiment, those differences that were significant were not sufficiently so to be of practical concern. A difference that was of practical consideration was in the quantities of nonsucrose constituents in the leaded sucrose filtrate compared to the standard lab thin juice in the second experiment. The differences for these nonsucrose constituents could have arisen through differential extraction of nonsucroses into the different extracts, component losses or transformation related to the chemical clarification procedure, or degradation of sucrose in the extraction process. The low quantity of total N in the lab thin juice is explained by the precipitation of many nitrogen-containing compounds, particularly proteins, in the laboratory thin juice process.

Since sucrose filtrate is extensively used for beet quality assessment, different methods of storing this filtrate were compared (Table 4). After 24 hours of refrigeration Na and AMN were significantly lower than in the samples freshly analyzed; whereas, K was unaffected by this treatment. On the other hand, the concentration of K was significantly altered by freezing the sample no matter what thawing procedure was employed; whereas, Na and AMN concentrations in samples that had been frozen were not significantly different from those of freshly analyzed samples. The differences among these treatments, although significant, were not large. VOL . 21 , NO 2 OCTOBE R 198 1

Table 3. Quality and chemical characters of sugarbeet extracts and juices over 4 years.

*lndicates significant difference (5%) from the standard lab thin juice within each year.

†lndicates significant difference (5%) from the first treatment within each experiment.

‡Not comparable statistically with the other treatments within each experiment due to dilution difference. 19 1 192 JOURNAL OF THE A.S.S.B.T.

Table 4. Means of freshly analyzed sucrose filtrate samples compared with identical subsamplcs handled by different procedures.

Lead—claritied sucrose filtrate Na K AMN mg/100 ml Freshly analyzed 7.82 21.71 3.56 Fresh, after 24 h at 4°C 7.66** 21.85 3.37** Frozen, thawed 18 h at 4°C 7.74 22.88** 3.54 Frozen, thawed 37° water 7.77 22.73** 3.52 Frozen, microwave thawed 7.87 22.01** 3.48

**Significant difference from the freshly analyzed samples by paired t-test (p - 0.O1) In Table 5 data from another experiment show that the Na and K concentrations in fresh brei sucrose filtrate were higher than in frozen brei filtrate which was then frozen and microwave-thawed, but the AMN concentrations were not different. The Na and K in the 1:1 extract of frozen brei were not differ- ent than either of the two filtrates. Only AMN in this 1:1 ex- tract was significantly higher than both filtrates. Hence, the concentrations of Na, K, and AMN in relation to sucrose were not consistently similar in sucrose filtrates, which, in turn, were not consistently different than the 1:1 extract of frozen brei. The correlations of these characters across the filtrates and extract also are shown in Table 5. These correlations are all positive, similarly high, and significantly greater than zero. It appears that concentrations of Na, K, and AMN measured in filtrates or beet extracts may be different quanti- tatively, but are proportionately similar. Hence, the type juice used may be immaterial provided the same juice and procedure are used consistently. Table 5. Means and correlations (r) of filtrate and extract samples.

Extract Na k AMN ----- mg/100 g sucrose 1 Fresh brei sucrose filtrate 404 a* 1102 a* 180 B* 2 Sue filtrate from 1:1 extract of frozen brei; filtrate fro- 342 b 953 b 195 b zen & microwave thawed 3 1:1 extract of frozen brei 363 ab 938 b 229 a VOL. 21, NO. 2, OCTOBER 1981 193

Table 5. Continued.

Correlations Na K AMN Extract 2 3 2 3 2 3 1 0.96 0.97 0.92 0.93 0.98 0.98 2 0.96 0.94 0.98 *Means within columns followed by the same letter are not significantly different (5%).

Our interest in these extracts and filtrates as samples for determination of quality and quality related compounds is in part governed by practicality. Obviously, any juice requiring preparation and immediate analysis is impractical for a large number of samples unless a rapid, fully automated analysis of the components of interest were in use. Among the extracts tested, the most practical would probably be immediate extraction with the extract being stored frozen for later analyses, or frozen brei being later thawed, ex- tracted, and analyzed. In the latter procedure, immediate freezing of the brei sample is important. From the standpoint of extract preparation alone, the sucrose filtrate would be an ideal juice with which to work as it is always available from the sucrose analyses. Its possible drawbacks are in the analytical complications and possible compositional alterations introduced by the lead or aluminum compounds (7) added in the sample defecation process. In our experience the 1 : 1 frozen brei extract is second in practicality to sucrose filtrate, followed by the 1:1 extract stored frozen, and the 1:1 extract analyzed immediately. Each of these can be prepared quickly and in large numbers. From a practical standpoint, we feel that the 1:1 frozen brei extract could provide an accurate assessment of the composition of beets. At the same time, this extract is one that can be practically utilized in all labs, even those with limited resources. It appears that useful quality component analyses can be made on any of several sample types with the important qualification that, within a lab, extract preparation and the subsequent method of handling samples must be 194 JOURNAL OF THE A.S.S.B.T.

standardized. The choice of extract type for quality measurements (at least of Na, K, and AMN) may be one of convenience, but data from different extract types should not be directly compared numerically. Thin juice purities of samples handled in four different manners are shown in Table 6. All four treatments are significantly different. The pressed juice which was analyzed immediately had the highest purity, 93.7%. It seems likely that this should be the most accurate measure since there was little opportunity for sample deterioration. The lower purity of limed juice stored frozen, 93.4%, is difficult to explain because there were only a few minutes between sampling the beets and adding lime to the juice, after which the juice samples were frozen and then thawed before analysis. Even though there may have been several hours involved in the freezing and thawing process, the pH of about 12 should have been an environment too hostile for significant microbial activity, although some enzymatic activity may have taken place. The still lower purity of juice from frozen brei, 92.8%, could have been caused by some sucrose degradation in the brei before freezing and during thawing. Limed juice stored 14 days at 4oC had the lowest purity, 92.1%.

Table 6. Thin juice purity of four pressed juice treatments.

Thin juice Treatment purity (%) RDS Pol Limed juice,, analyzed immediately 93.7 a* 11.54 43.42 Limed juice,, stored frozen 93.4 b 11.55 43 .28 Limed juice from frozen brei 92.8 c 10.46 38.82 Limed juice,, stored 14 days at 4°C 92.1 d 12.65 46.98

*Means with the same letter are not significantly different (5%). The components of purity in Table 6, RDS and polari- zation, indicate that the sucrose content declined in limed juice stored frozen and in juice from frozen brei, while RDS (soluble solids) decreased in the latter juice. In the limed juice stored 14 days at 4° C the RDS apparently increased, but the soluble solids consisted of proportionately VOL. 21, NO. 2, OCTOBER 1981 195

less sucrose so that the resulting purity was significantly lower than all other juices. This increased RDS apparently resulted from solubilization of insoluble nonsucrose compounds during the 14-day storage period. The comparison of pol and GC sucrose determinations in 10 cultivars is shown in Table 7. No comparison within cultivars was significantly different (25 samples per mean), and the means across cultivars were identical, 14.4%. Hence, across these cultivars with wide ranging sucrose values, the pol and GC sucrose determinations were the same.

Table 7. Polarimetric and gas chromatographic sucrose and glucose content of 10 cultivars in percent of fresh weight.

Sucrose (%) Cultivar Pol GC Glucose(%) US H9B 14.9 cd* 14.9 c* 0.14 c* US H20 14.3 d 14.0 d 0.23 b HH 10 15.6 abc 15.6 be 0.15 e GW 359 15.9 ab 15.8 be 0.20 be GW Mono Hy 16.1 ab 16.3 ab 0.15 e Exp. hyb 1 16.4 a 16.8 a 0.16 c Exp. hyb 2 15.3 be 15.5 be 0.17 c Exp. hyb 3 15.9 ab 15.9 b 0.16 c Sugar X fodder beeL, F1 11.9 e 11.8 e 0.18 b Fodder Beet 7.6 f 7.5 f 0.43 a Mean 14.4 14.4 0.20 *Means within columns followed by the same letter are not signifi- cantly different (5%). The glucose means in Table 7 show that relatively small quantities of glucose are present in the eight sugarbeet cultivars, averaging 0.17% on a fresh weight basis, compared to 15.6% sucrose. The fodder beet contains considerably more glucose (2.5 times that in sugarbeets) and less sucrose (about half that in sugarbeets). The sugarbeet X fodder beet hybrid was essentially intermediate for sucrose, but similar to sugarbeet in glucose content.

SUMMARY Several experiments were conducted to compare methods of sugarbeet (Beta vulgaris L.) sample preparation and preservation for sucrose and quality analyses. Samples treated with the preservative phenylmercuric acetate (PMA) 196 JOURNAL OF THE A.S.S.B.T.

were not different from controls for sucrose, refractive dry substance, raw juice purity, and thin juice purity. Among seven nonsucrose components of purity, amino nitrogen and conductivity ash were present in significantly lower quantity in the PMA treated samples. In separate experiments comparing fresh and frozen brei, sucrose contents of the two brei treatments were the same in beets grown at low, optimum, and excess nitrogen fertility. Three methods of juice extraction were found to have similar thin juice purities. However, in two of three experi- ments the extracts had significantly lower thin juice purity than standard limed pressed juice stored frozen. Differences among seven nonsucroses in the extracts were significant in some cases but not practically important. Each of the extracts studied should provide a reliable purity sample. Practically, the 1:1 frozen brei extract should provide an alternative method which permits an accurate assessment of the constitution and composition of beets. However, data from different extract types should not be compared numerically.

The Na, K, and AMN contents of lead-clarified sucrose filtrate and brei extract were significantly affected by some filtrate treatments. However, high correlations among the different filtrate treatments indicated that the juice treatment or type may be immaterial provided the same juice and pro- cedure were used consistently. Three methods of storing brei or limed juice samples all exhibited lower thin juice purity than immediately analyzed juices.

Glucose in 10 diverse cultivars ranged from 0.14% to 0.43% of fresh root weight. Sucrose measurements by polari- zation and gas chromatography were not different in any of these 10 cultivars. VOL. 21, NO. 2, OCTOBER 1981

LITERATURE CITED (1) Brown, R. J. and R. F. Serro. 195-4. A method for determination of thin juice purity from individual mother roots. Amer. Soc. Sugar Beet Technol. Pro. 8(2):274- 278. (2) Carruthers, A. and J. F. T. Oldfield. 1961. Methods for the assessment of beet quality. Part I - Purity determination using a clarified extract from brei. Int. Sugar J. 63:72-74. (3) Cormany, C. E. 1950. Delayed sucrose analysis of pulped beet samples. J. Amer. Soc. Sugar Beet Technol. 541-543. (4) Maag, G. W. 1969. Rapid digestion procedures for determination of metallic ions and total nitrogen in sugarbeet samples. J, Amer. Soc. Sugar Beet Technol. 15:361-367. (5) Maag, G. W., R. J. Hecker and P. A. Whitaker. 1972. Nitrogenous compounds in sugarbeet juices. J. Amer. Soc. Sugar Beet Technol. 17:154-164.

(6) Maag, G. W. and G. H. Sisler. 1975. False polarization: quantitation and characterization of sugarbeet processing juices. J. Amer. Soc. Sugar Beet Technol. 18:257-263. (7) Martin, S. S. , R. J. Hecker and G. A. Smith. 1980. Aluminum clarification of sugarbeet brei extracts. J. Amer. Soc. Sugar Beet Technol. 20:597-609.