TECHNICAL BULLETIN No. 53 JUNE 1963

The Comparative Effects of Calcium Carbonate and of Calcium Silicate on the Yield of Sudan Grass Grown in a Ferruginous Latosol and a Hydrol Humic Latosol

N. H. MONTEITH and G. DONALD SHERMAN

HAWAII AGRICULTURAL EXPERIMENT STATION, UNIVERSITY OF HAWAII The Comparative Effects of Calcium Carbonate and of Calcium Silicate on the Yield of Sudan Grass Grown in a Ferruginous Latosol and a Hydrol Humic Latosol

N. H. MONTEITH and G. DONALD SHERMAN

UNIVERSITY OF HAWAII COLLEGE OF TROPICAL AGRICULTURE HAWAII AGRICULTURAL EXPERIMENT STATION HONOLULU, H AWAII J UNE 1963 T ECIINICAL B ULLETIN No. 53 ACKNOWLEDGMENT The authors gra tcfully acknow ledge the assistance of the staff of th e Experiment Station of the H awaii an Sugar Planters' Association in pro­ viding greenhouse, photographic, and laboratory facilities, and for advice on sta tistical and analytical methods. Research funds on this proj ect were pro vid ed by the Hawaiian Sugar Planters' Association Experiment Station under a coope rative research agreemcnt with the Department of Agronomy and Soil Science. Funds and materials we re also provided by the Tenn essee Valley Authority, Contract No. TV21132A.

THE AUTHORS N. H. MONTEITH was In structor in Agricultur e, University of Hawaii, 1961-1962. DR. G. DONALD SHERMAN, Associate Director of the Hawaii Agricultural Experiment Station, is Senior Soil Scientist at the Hawaii Agricultural Ex­ periment Station and Senior Professor of Soil Science, University of Hawaii. CONTENTS PAGE

INTRODUcrION 5

LITERAT UHE REVIEW 5

Effect of Calcium Carbonate on Phosphorus Availability 5

Effect of Calcium Carbonate on Other Factors 7

Effect of Calcium Silicate on Phosphorus Availability 8

Effect of Calcium Silicate on Other Factors 8

EXPEmMENTAL PROCEDUHES 9

Soils . 10

Tr eatm ents 10

Growth. 11

Harvestin g 11

Leachates . 11

Plant Chemical Analysis 11

Soil Ch emical Analysis 12

EXI'ElUMENTAL RESULTS 12

Yield 12

Plant and Soil Analysis 15

Leachate Studies 32

D ISCUSSION . 35

CONCL USION 36

LITERAT UHE CITED 37 (Continued ) Contents, Continued

Figures PAGE 1. Relationships between yield and phosphorus contents of plant material and soil extracts 17

2. Relationships between yield and calcium contents of plant material and soil extracts . · 20

3. Relationships between yield and aluminum contents of plant material and soil extracts · 24

3A. Relationships between aluminum content of roots and phosphorus content of roots , and also between aluminum and calcium 25

4. Relationships between yield and pI-I of th e soil 26

5. Relationship between cation exchange capacity and aluminum content of th e soil extract · 27

6. Relationships between yield and cation exchange capacity of th e soil . · 28

7. Relationships between extractable aluminum and exchangeable calcium in th e soil · 29

8. Relationship between aluminum content and pH of the second leachate . · 33 The Comparative Effects of Calcium Carbonate and of Calcium Silicate on the Yield of Sudan Grass Grown in a Ferruginous Latosol and a Hydrol Humic Latnsol ' N. H. MONTEITH and G. DONALD SHEHMAN

INTRODUCTION Several current field experime nts in th e Hawaiian sugar industry have shown that liming has increased both yield of sugar and phosphorus uptake by th e plant. Th ese results have been of considerabl e interest to the industry and have brought to focus the whole qu estion of th e value of soil am endments in sugar cane production in the Hawaiian Islands. Early experime nts by McGeorge (1924) had shown beneficial results from th e application of soluble silicat e to sugar cane soils. H e attributed th e beneficial efFect on sugar cane growth to a greater availability of phosphorus in the soil. Sherm an et al. (1955) obtained similar results using a number of Hawaiian soils. More recently, Clements (1962) and Rixon (1963) reported , respectively, effects beneficial to yield and to soil phosphorus availability, from studies th ey made on a number of sugar cane soils on the Hamakuu coast. This interest led to th e initiation of this study, which had as its obj ec­ tive a comparative study of th e effects of application of calcium silicate and calcium carbonate on th e growth of plants and on th e avail ability of phosphorus when applied to a soil having alumi num oxides in a fairly good state of crystallinity agai nst a soil in which aluminum exists in a highly hydrated colloidal oxide system.

LITERATURE REVIEW Effect of Calcium Carbonate on Phos pho rus Av ailability Th e effect of calcium carbonate on phosphorus uptake has been studied and recorded for many years. Johnston (18 49) , Ruffin (1852), and Hilgard (1907) discussed the question at an early stage in the research . A considerable amount of work has been don e in Germany, where Engels (1936) came to th e conclusion that lime prevented th e formation of insoluble iron and aluminum phosphat es. Kottgen and jung (1941) showed that small amounts of lime increas ed the phosphorus available in th e subsoil and that deficiencies of phosphorus could be corrected by adding lime . Mitscherli ch ( 1947) found that phosphorus fixation decreas ed with applications of 15 gm. lime per pot. Geri cke (1951) reviewed some

1 This tcclmical bulletin is part of a thesis submitte d by th e senior author to th e Gra d uate School of th e University of Hawaii in partial fu lfillm ent of th e requirem ents for the Mast er of Scienc e degree. 6 HAWAII AGlIIC ULTUIIAL EXPElIIl\IENT STATION

of the evidence on liming from work perform ed in Germany. His inv estiga­ tions showed that liming increased the phosphorus availability on strongly acid soils by 0.7 mg . per 100 gm. but not when the pH of th e soils was above 6. He considered that lime corrected "unfavorable" conditions for plant growth and this enabled the plant to utilize the less soluble form s of phosphorus. Several workers have thought that organic phosphorus may be rel eased by lime or by the breakdown of organi c matter. Ghani and Aleem (1942) , in India, suggested that the increase in phosphorus avail­ ability, through the application of lime, was du e not to a decrease in th e formation of aluminum and iron phosphates, but to the release of phos­ phorus from organic matter, resulting from a change in reaction which fa vored microbial action and the breakdown of the organic matter. Salon en (1946), in Finland, reported that liming increased the breakdown of organic phosphorus. Mattson ct al. (1950), in studying a limed and an unlimed Podsol, thought that th e formation of B humus by limin g mobilized phosphorus, as more available phosphorus occurred in th e subsoil of th e limed Porlsol than in th e subsoil of th e unlim ed soil. There is also evidence that under certain circumstances lime applications can decrease phosphorus availability. Mate and Molnar (1956 ), in Hun­ gary, showed phosphorus fixation increased with liming. Loo, Yu, and 'Van (1956) , in China, stated that increased fixation is not encountered until liming increased the pH of the soil to 7.5. Lawton and Davis (1956), working on acid organic soils, found increased phosphorus fixation due to liming was apparently caused by a decrease in the proportion of H 2P04­ to HP04-- ions. Phosphorus can be fixed in acid soils by combining with iron and aluminum, and, in alkaline soils, by being precipitated as calcium phosphates. The increase in phosphorus availability du e to liming seems to be associated, then, with soils having a predominating iron-aluminum system. Thi s conjecture appears to be supported by the work of Yudin (1958), in Russia, who found that lime increased the utilization of fertilizer phos­ phorus by the plant in the Krasnozem soils more than in oth er types of soils. Similar work with tropical soils is still relatively undeveloped. McG eorge (1924) , in Hawaii, suspected that liming increased th e phos­ phorus uptake in sugar cane. Hardy (1934), in Trinidad, by liming, obtained a 39 to 67 percent increase in ava ilable phosphorus. Beater (1945) reported a 20 percent greater phosphorus up take in maize; and nitrogen and calcium uptake were also hig her. Monteith et al. (1958), in Fiji , found in a study of soil pH and ava ilable phosphorus that the expect­ ancy of high soil phosphorus increased as th e pH increased to approxi­ mately pH 7.5, after which it decreased. They (1959) also recorded lim­ ing with coral sand produ ced an increase in nitrogen uptake in sugar cane, especially at low fer tilizer nitrogen levels. Schroo (1954) demonstrated

that limi ng increased th e P205 content of sugar cane juice by 40 percent. CALCIUM CA Hn ON ATE A ND C A LC I UM SI LICATE AND YI ELD I N LATOSOLS 7

Clements (1962 ) has found, upon liming Hydrol Humic Latosol soils in Ha­ waii , that marked increases occur in th e phosphorus uptake by sugar cane. Leaching expe riments have shown th at limin g promotes the leaching of phosph ate ions. MacIntire et al. ( 1947) ha ve full y illustrated this in a 12-year leaching expe rime nt. Th ey detected the phosphorus by che mical means ; oth er workers have used radioactiv e p:l2 to trace the mov ement of phosphorus in soil columns ( Bouldin and Black, 1954; Heslep and Black, 1954 ).

Effect of Calcium Carbonate on Other Factors Th e applica tion of calcium carbonate to soil can affect oth er factor s whi ch can cause growth stimulation. Th e following effects can be prod uced in the soil by liming: 1. Heduction of the aluminum or manganese toxicity in a soil ( Mulder and Gerretsen, 1952 ). 2. General increase in the effectiveness of othe r soil element s in plant nutrition ( Truog, 1953 ). 3. Develop ment of physical conditions more favorable for plant growth in soil (Colema n et al., 1958 ). 4. Improvement of microbial nitrogen fixation in soils ( Black, 1957 ). 5. Supplying of calcium as a nutrient in very acid leached soils (Ayres, 1961). F ried and Peech ( 1946) discussed calcium as a plant nutrient in th e introduction of their pap er and came to the concl usion that supplying additiona l calcium to the plant is generally not important. Th ey stated , however, that with soils of equal calcium conten t lime often gives better results than gyp sum . As indi cated above, several workers have reported that limin g reduces th e "active" aluminum content in th e soil and therefore the so-called "toxicity" du e to aluminum is correspon dingly red uced . Much of thi s work has been carried out by Russian and German soil scientists. Chizhevs kii and Korovkin (1958) , Peterburgsky (1941), Peive ( 1939 ), and Fatchikina (195.'3 ) all found that active aluminum was reduced by the action of lime and that plant growth improved. It has been observed by Menchik ovsky and Puffeles ( 1938) that calcium salts can be responsibl e for reducing active aluminum in soils. Chernov and Belyaeva (1946), in th eir interestin g studies on th e nature of soil acidity, came to th e conclusion that calcium uptake is suppressed com­ pletely by AICI:. at pH 4 to 5. Schm ehl , Peech, and Bradfi eld ( 1950), Moschler, Jones, and Thomas ( 1960), and Hixon (1963 ) have studied the effects of aluminum on othe r elements and th e influence of lime on Al activity. Duthie and Bourne ( 1939), in British Gui ana, and several Japanese workers (Hosoda, Takata, and Ogih ara, 1957) ha ve also found a reduc­ tion in "active" aluminum occurs du e to liming. 8 HAWAII AGIIICULTUHAL EXPEIUMENT STATION

Effect of Calcium Silicate on Phosphorus Availability The effect of calcium silica te ( bas ic slag) on phosphorus availability has also been studied extensively. Even as early as 1906, Hall and Mori­ son, at Rothamsted Experimental Station, Englan d, concl ude d th at sodium silicate responses were simi lar to phosphorus responses. Scheidt (1917) compared calcium silicate and calci um carbonate treatments and found calcium silica te gave a better response. Con ner (1921) also cons idered th at th is difference was due to the grea ter ability of calcium silicate to precipita te active iron and aluminum. McGeorge (1924), in Hawaii, analyzed soils for silica and found that th e lower the silica content the more likely a response to phosphorus. H igh silica meant high phosphorus in the juice of sugar cane. Sherman et al. (1955) obtained increased utilization of phosphorus with silicate application, but did not find a relation ship to silica con tent of soils. Scars eth (1935) obtained a growth increase by the use of silica te com­ pounds which was similar to that obtained by the usc of phosphorus com­ pounds. Toth (1939 ) showed that the soil phosphorus complex broke down with the use of high-pH anions such as SiO ;j and OH; and Low and Black ( 1948) indicated that the reverse reaction was true wh en silica was released from clay minerals by th e use of phosphorus compounds. This sug gested that additions of silica would slow down the release of phosphorus from clay min erals and thus tend to prevent phosphorus from being absorbed by clays . Knickmann ( 1949), in Germany, found that the loss of phosphorus in the drainage water was less with slag than with lime. Scho llenberger (1922) noted that there wa s a greater phosphorus up take with lime and silica than with lime alon e, and that the response to lime plus silica was a vegetative response and therefore similar to a nitrogen response. In this regard, Ziemiecka (1929) reported that the phosphorus nutrit ion of Azotobacter is assisted by the addition of colloidal silica.

Effect of Calcium Silicate on Other Factors It has been pointed out by Fatchikina (1953) that a silicate (dunite), as well as liming, can be effective in reducing "toxic" levels of alu minum . MacIntire, Winterberg, Dunham, et al. ( 1946) showed that "glassy" slags

can be conver ted to calcium carbonate and that the CO 2 required for the conversion could be derived from bacterial activity . Crystalline calcium silicate, howeve r, is not easily converted to calcium carbonate. The mech­ anism invo lved whereby calci um silicate pr events the absorption of phos­ phorus by clays an d precipitates ac tive iron and aluminum, and perhaps even sup plies silicon to the plant, is not clear, even though it has been postul ated tha t calcium silicat e ac ts in the same manner as calcium car­ bonate. Little work has been done on this aspect of th e role of calcium silicate in tropical soils. CALCIUM CARBONATE AND CALCIUM SILICATE AND YIELD IN LATOSOLS 9

A study of the data and a review of th e literature ha ve led to the forma­ tion of the following hypotheses relating to th e mechanism of yield increase by liming: 1. Th e br eakdown of organic matter a. chelates "toxic" clements such as aluminum and removes them in the drai nage water. b. releases min eral phosphorus and other plant nutrients. 2. Calcium is a limiting factor in growth in lime-treated soils. 3. Liming induces better crystallization in th e AI( OHh system of the soil, by decreasing "toxic" amounts of aluminum.( T his system is known to exist in at least one of the soils used in this study. )

4. Fixed phosphorus is released by the action of an OH- or Si03- ­ ion, and thus growth is improved. This should occur only if phosphorus is a limiting factor, or if phosphorus decreases a "toxic" fac tor such as alu minum. 5. Increased microbial activity is accompanied by increased nitri­ fication. 6. By incrcasing th e pH of the soil, other clem ents, if toxic to the plant, ar e red uced in concentration; or, the lack or insuffi ciency of some element, wh ich has been limiting plant growth, may be corrected by liming. An expe rime nt was designed to test some of th ese hypotheses, and th e resu lts arc presented in this report.

EXPERIMENTAL PROCEDURES A pot experiment was designed to obtain results from two differen t soils. In each soil, half the treatment s cons iste d of 3 levels of calcium car­ bonate ( c.p. grade) and the other half, 3 levels of calcium silicate (c.p. grade). Ea ch of these 12 levels was trea ted with 3 levels of monocalcium phosphate dihydrate (c.p. grade); there were three rep lica tes of each treat­ ment ( 108 individuals in all ). The layout was a randomized block desig n. Akaka or PuM Soil ------Calcium silicate /I~ SO 5, . 52 /1\ /1\ //\ Po PIP2 PI' PIP" PI' P,P"

P = phosphate L = lime 5 = calcium silicate 10 H AWAII AG IIICULTURAL E..'l:PEIII MENT STATION

Soils Akaka Silty Clay was collected from the plow layer of field 2 of Laupa­ hoehoe plantation, Hawaii, immediately after the harvest of the sugar can e crop. The other, a Pu hi Silt Loam, was collected at Grove Farm planta­ tion, Kauai, likewise from the plow layer and also immedia tely aft er th e harvest of the sugar can e crop Akaka soil is a Hydrol Humic Latosol which drastically changes its characteristics on excessive dryin g; the cation exchange capacity is lowered (Kanehiro an d Chang, 1956 ), an d th e soil will not rewet to moisture con­ tents found normally in the field. Precaution s were th erefore tak en to prevent excessive dr ying. This soil has a high content of hydrated colloidal amorphous aluminum, and iron oxide and hydroxide gels. On drying, gibb­ site will crystallize with a conside rable increase in particle size (Sherman, 1957 ). Puhi soil is a Humic Ferruginous Latosol. The characteristics of this soil are altered on dr ying, but not to the sam e extent as those of Akaka soil (Trouse, 1960 ). Precautions were also taken with the Puhi soil to prevent drying. T he aluminum and iron oxides exist in these soils in crystalline min eral form as gibbsite, goethite, hematite, and ma ghemite. Th e Akaka soil for this expe riment was pa ssed through a ~; - i nch-mes h sieve and thoroughly mixed in a mechanical mixer. The Puhi soil was pa ssed through a 5-mm . sieve and mixed. At this point, the moisture con­ tent of the Akaka soil was 107 percent and that of the Puhi soil was 42 percent. Volum etri cally, 4500 gm. wet weight of Akaka soil occupied approxima tely 8500 cc.; and a similar wet weight of Puhi soil occupied 4000 cc. Approximately half of the volume of Puhi soil taken from th e field consis ted of rocks; thus 4500 gm. would occupy approximately 8000 cc., and therefore 4500 gm. were tak en for each soil as an approximate adjustment to obtain equal field volum es.

Treatments In a stainless steel rotar y mixer, each of the calcium carbonate and cal­ cium silicate treatments was thoroughly mixed with a 4500-gm. sample of soil and then each mixture was placed in a Mitscherlich pot. The SI and

L 1 treatments were at 5000 pounds per acre, or 18.12 gm. per pot. The S2 and L2 treatments were at 20,000 pounds per acre, or 72.48 gm . per pot. These pots, with proper precautions to prevent moisture loss, were then stored for 7% weeks to allow time for th e pH of the soil to reach equilib­ rium befor e planting. At the end of this period, th e phosphorus treat­ ments were applied . The chemical was stirred into th e top 1)£ inches of the soil. The treatments were PI at 500 po unds monocalcium phosphate per acre, or 1.81 gm . per pot; and P2 at 2000 po unds monocalcium phos­ phate per acre, or 7.24 gm . per pot. CA LCIUM CAH BONATE AND CA LCIUM SILICATE AND YIELD IN LATOSOLS 11

Growth Pots were planted with Sud an grass seed (California No. 23) an d sup­ plied with 0.9 gm. urea and 0.9 gm . potassium chloride per pot at approxi­ mately 3-week intervals; they were wa tered tw ice a day with tap water.

Harvesting Th e Sudan grass was harvested at the first sign of flowering, 6 weeks after planting, and placed in a hot-air oven at 65° C. for 1 week. The dry weight yields were recorded. Plant material was then ground in a Wiley Mill and bottled for analysis. Th e root-bound block of soil was removed from th e pot and cut in half. The soil from one of these halves was subsampled and bottled in a moist state for soil analysis (pH was tak en imm ediately) . Roots were separated from th e other half by jetting th e soil free with a high-pressure water jet. The roots were then oven-dried at 60° C., weighed , and ground in a Wil ey Mill. Th ey were subsequently examined under a binocular microscope at 80X power to determine wh ether contamination by soil particles had occurred .

Leachates Although the pots were kept moist, no water passed through the pots into the collecting pan until 3 days aft er planting, at which tim e 600 cc. of water had been added to each pot. Twenty-five ml. of th e leachate were tak en from each collecting pan and th e amo unts from each of th e three rep licates for each treatment were combined to give 75 ml. for each tr eatment. The pH of each combined leachate was recorded, using a Beck­ man pH meter. Phosphorus analysis was carried out, using the method of Truog (1953). A week prior to harvesting, all of th e collecting pans contained leachate. A total of 150 cc. was taken from two of th e repli cates and a bulk sample was made up. The pH and phosphorus content of this sample were recorded ; and the aluminum content was determined by th e aluminon method described by Ch enery (1948) .

Plant Chemical Analysis Plant samples whi ch had been previously ground and dried were redried at approximately 70° G and placed in a desiccator. From th ese, 2 gm. of plant top samples and 1 to 2 gm. of root samples were taken for chemical analysis. Th ese sampl es were then ignited in a mu fIl e furnace at 480° G , . taken up in conce ntrated hydrochloric acid, evapora te d to dryness, and baked on a hot plate for a period of 4 hours to complete silica crystallizat ion . Following this , each of th ese samples was th en taken up in 3 N hydro­ chloric acid and mad e up to volume. Aliquots were tak en for : (1) phos­ phorus analysis (by th e method of Truog and Meyer, 1929); (2) calcium 12 HAWAII A GIU CUL T U HAL EXPERI MENT ST ATION

analysis (by the Beckman DU flame phot ometer with photomultiplier, usin g a compensated standa rd developed by the Plant Physiology Depart­ ment of th e University of Hawaii); and (3) aluminum analysis (by the aluminon method of Chenery, 1948) . Th e same meth ods of analysis were used for both top and root samples. Soil Chemical Analysis All samples were in a moist condition an d therefore the moisture con­ tent of each sample was determined in ord er to convert all results to an oven-d ry weight basis. The pH was determ ined on th e soil as a soil-wat er paste; the paste was allowed to stand for 1 hour before recording th e pH. Extractable phosphorus was determined by using th e 0.02 N sulfuric acid extractant (Ayres and H agih ara, 1955) and carrying out the analysis by the method of Truog and Meyer (1929) . Ext ra ctable aluminum an alysis was carried out according to the me thod of Pratt (Nelson, 1958), usin g 100 ml. of N ammonium acetate and 0.1 N barium chloride solution (pH = 4.8) as th e extractant on 10 gm. of moist soil. Cation exchange cap acity was determined on 20 gm. of moist soil by saturating the soil in 250 ml. of N ammonium acetate overnight with inter­ mittent shaking . The soil was filtered, and th e filtrate was retained for calcium and potassium determinations. Excess ammonium acetate was washed from the soil with ethanol, and the ammonium wa s leached out by N potassium chloride solution adjusted to pH 2.5. The leachate was made up to volume, and ammonia was determined by using th e Nessler reagent method. Cal cium in the ammonium acetate was analyzed by use of the Beck­ man DU flame photometer with photomultiplier. This method has been developed by the Hawaiian Sugar Planters' Association (Ayres, 1961). Potassium was also determined by using the Beckman DU flame photo­ meter.

EXPERIMENTAL RESULTS Yield The yield results for th e pot expe riment are shown in tables 1 and lA. Analysis of variance for the yield is shown in tabl e 2. In both soils, the yields of Sudan gras s were significantly increased by each increment of phosphorus. In the Akaka soil th e effec t of rates shows a linear relationship, whereas in the Puhi soil the relationship is curvilinear. Lim e and calcium silicate applied sep arately at the rate of 5000 pounds per acre increased the yield in the Akaka soil but did not increase yield in th e Puhi soil. Lime at the 20,000-pound-per-acre rate tended to decrease yield in th e Akaka soil and did significantly decr ease yield in th e Puhi soil; however, calcium sili­ cate at th e 20,000-pound-per-acre rate increased yield in both the Akaka and Puhi soils. CALCIUM CARIJONATE AND CALCIUM SILICATE AND YIELD IN LATOSOLS 13

TABLE 1. Effect of applica tions of liming materials and monocalcium phosphate on yields (in grams of dr y matter) of Sudan grass grown on Akaka and Pu hi soils

CA LCIUM SILICATE LIME APPLIED, P I IOSPHATE lh / acre API'LJED, A PPI~I ED, lb/ acre Ih/ acre 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 19.8 33 .7 28 .3 19.8 25.7 41.7 500 26.2 46 .3 42.7 26 .2 41.7 63.7 2000 38.3 64.7 58 .0 38 .3 59 .7 83.3

PU HI SOIL 0 35 .8 28.6 24.0 35.8 35.6 49 .0 500 72 .8 69.0 305 .6 72.8 66 .3 8.5.3 2000 8 05 .8 93.3 053.6 85.8 84 .3 92.0

TABLE l A. Effect of applications of limin g mat erials and monocalcium pho sphate on yields (i n grams of dry matter) of roots of Sudan grass grown on Akuka and Puhi soils

CA LC IU M SILICATE i. rxu: API)LJED, PHOSPHATE lh /acre APPLIED , APPLIED, Ih/acrc Ill/ acre 0 5,000 20 ,000 0 5,000 20 ,000

AKAKA SO IL o 3.0 3.9 4.4 3.0 3.4 05 .1 500 2.6 6.1 7..5 2.6 3.8 8.1 ;WOO 4.6 12.6 10.1 4.6 9.2 13.9 PUJ-ll SO IL o 5.6 4.3 2.9 5.6 4.05 8.7 05 00 12.1 10.9 4.8 12.1 10.9 12.9 2000 13.9 14 .05 7.0 13.9 13.6 17.2

The over-all intera ction of phosphorus X calcium ra tes is not significant, but it is important to note that th e soil's phosphorus X calcium interac­ tion is significant; this interaction is evident in the Akaka soil but not in th e Pu hi soil. 14 H AWAII AG lIICULTUUA L EX PElII MENT STATION

T ABLE 2. Sign ificance of F values in th e ana lysis of variance of various factors in pot expe rime nts with Snda n grass on Akaka and Puhi soils

T OPS HOOTS SOUHC E Yield %1' %Ca ppm Al I ppm Al Soils ** * Pho sphorus (I') ** ** * Ratcs of calcium (Ca) ** ** Source of calcium ( CS) ** * ** ** S XP ** ** S X Ca ** S X CS ** ** ** P X Ca P X CS Ca X CS ** ** ** S X P X Ca ** S X l' X CS * S X Ca X CS * ** P X Ca X CS * ** S X P X Ca X CS ** Mean 5 1.8 0.111 0.D3 130 .6 240 4 Cocfficicnt of variation 13.46% 9.82% 10.56% 27.98% 2D.82% Sx 4.028 0.0065 0.057 21.11 717 Approximatc L.S .D. 12 gm. 0.020% 0.]70% 63.0 ppm 2150 ppm

** Si g n ifica n t a t 1% level. * Signiflcan t at 5% le vel.

Inasmuch as a study of the depressed yield at the L 2 level is conside red outside th e scope of this investigation, the results will be only bri efly dis­ cussed, and those for the L 2 and S2 levels have been omitted from all graph­ ical relationships. The results of th e root chemical analysis in the Puhi series are considered unreliable becaus e there was a possibility of root con­ tamination due to soil particles. Contamination in the Akaka series, how­ ever, is considered unlikely, as high-yielding plants showed a low aluminum content. Root yield is presented in table LA. In both soils, th ere was a definite response in root growth to applications of phosphorus and also to the application of calcium silicate. In the Puhi soil, application of high amounts of lime caused a decrease in root growth. CALCIUM CAHlJONATE AND CALCIUM SILICATE AND YIELD IN LA TOSOLS 15

Plant and Soil Analysis Phosphorus: Phosphorus wa s extracted from th e soil by using 0.02 N sulfuric acid, and the results show a significant in crease in P with each level of added phosphorus (table 3). Th e nil P level value of th e Puhi soil indicates that there may have been insufficient phosphorus for optimum plant growth. The nil P level of the Akaka soil indicates that there should be sufficient phosphorus for growth in this soil. For the Puhi soil, the available phosphorus ranged from an average of 8 ppm for nil P to 46 ppm for soil receiving the highest P application, while for the Akaka soil the same treatments gave 33 ppm and 98 ppm, respectively.

T AB L E 3. Elfeet of applications of liming mat eri als and monocalcium phosphate on th e amount of available phosphorus (as ppm P ) extracted from Akaka and l'uhi soils

CA LCIUMSILICATE LIl\fE AI 'PLJED, PHOSPHATE lh /ncr e AI)PLIED , APPLIED, lb / aere lh/ acre 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 41 37 25 41 26 32 500 49 61 45 49 54 42 2000 82 107 106 82 78 94 PUHI SOIL 0 9 8 10 9 7 9 500 17 20 23 17 15 15 2000 40 50 50 40 39 47

The Puhi soil studies show phosphorus content in the roots ( table 4 ) increas ed with added phosphorus; but the Akaka soil st udi es show no significant increase in phosphorus concentration occurred wh en phosphorus was added , and, mor eover, a decreas e occ urred wh en lime or calcium sili­ cate wa s added . Th e phosphorus content of tops of Sudan grass is presented in table 5. Th e significance of the interactions presented in table 2 indicates that the percentage of phosphorus generally increased with added phosphorus. In the Akaka soil series, compa red with the Puhi series, there wa s little increase in phosphorus conten t from the application of phosphorus at the rate of 2000 pounds per acre. Both lime and calcium silicate increased the percentage of phosphorus uptake in the Puhi series, but only at the high 16 HAWAH AG IUCULTUIIAL E XPElIIMENT STAnON

T ABLE 4. Effect of applications of liming mat eri als and mo noca lcium ph osph at e on th e phosphorus con ten t ( as percent 1') of root s of Sndan grass grown on Akaka and Pnhi soils

CALCIUJ\f SILICATE L II\fE A P PL IED, PHOS P HATE lh/acrc A PPLIED, A PPLIED, Ih/aere lh/ acre 0 5,000 20 ,000 0 5,000 20,000

AKAKA SOI L 0 0.125 0.08 2 0.106 0.125 0.111 0.101 500 .135 .109 .124 .135 .098 .097 2000 .119 .104 .089 .119 .113 .089 l' UHI SOI L 0 .091 .079 .111 .oo i .085 .069 500 .074 .080 .102 .074 .078 .086 2000 .105 .124 .138 .105 .114 .148

level of phosphorus; there was no marked increase in the uptake of phos­ phorus by plants grown under identical treatments on the Akaka soil. The phosphorus content of the plants receiving nil P on th e Akaka soil wa s high er than the ph osphorus content in plants grown under identical treat­ ments on the Puhi soil, thus presenting further evidence that the plants grown in the Akaka series nil P treatment pots received sufficient phos­ phorus from th e soil, wh ereas those in th e Puhi series did not. Th e analysis of the yield data an d chemical composition of th e Sudan grass and soils is presented in figure 1. Th ere is a significant re lationship between yields of Sudan grass grow n on the Puhi soil and th e ph osphorus content of the top s and the root s of the plants and also the am ount of available phosphorus in the soil. Th ere is no relationship between yield of Sudan grass grown on the Akaka soil and th e chem ical composition of th e plant top s; but there is a negative relati onship wi th the ph osphorus con­ tent of th e plant roots and a positive one with the available ph osphorus in the soil. Calcium: In both soils, application of lime or calcium silica te increased the excha nge able calcium content. The data obtained ar e pr esented in table 6. The highest content of exchange able calcium was obtained from the application of lime to the Akaka soils, and ran ged from 1.2 milli equiv­ alents per 100 gm. for the soil of the control to 24.2 milli equivalents p er 100 gm. for th e soils receiving 10 tons of lime per acre; the range for the sam e treatments on the Puhi soil was from 0.9 milli equivalent per 100 gm. to 13.9 milliequivalents per 100 gm., respectively. The con tent of exchange­ able calcium of the soils receiving calcium silica te was also increas ed, b ut YIELD vs PLANT TOP ANALYSIS

100 AK AKA 10 0 PU HI •• 0 Q ••• • e 0 0 • '" ...J .... 50 50 >- .. ..c • • ft e A Y s ll 7LOG X Icr- 158.4 e. ..

o I I .0L'60 .100" .150 .850 "loP "loP YIELD vs ROOT ANALYS IS

10 0 r AKAKA 10 0 PUHI e • Y·1 2 1.1- 717.5X • • • •• 0 " .. ...J .... 50 50 >- • / • .-

Yo 199.7 L OG IcrX - 33 3

0 .0°90 .110 .130 .150 .0 5 .10 0 .150 "lo P "lo P YIELD vs SOIL ANA LYSIS

10 0 AKAKA 100 PUH I • : ~...... o ;. ~ 50 50 >- . , • • . " f· ./ oI4 o67 , y .22+ .47X Y .12 LOG X -18.43

OL--__-'- --I. --J OL--..l.-_-'-_--L_-.l_----l 20 60 100 14 0 o 10 20 30 40 50 ppm P ppm P

FIGUIIE 1. Rela tionships between yield and phosphorus cont ent s of plant material and soil extracts. 18 HAWAII AGHICULTUHA L EX PEHI MENT STATION

TABLE 5. Effect of applications of liming materi als and monocal cium phosphate on th e phosphorus content (as percent 1') of tops of Sudan gra ss grown on Akaka and Puhi soils

CALCIUIII SILI CATE LI l\I E APP L IE D, Pl!OSP llATE lh / acre A P PLIED, A PPLIED, lh / ucrc lh / acre 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 0.103 0.101 0.124 0.103 0.105 0.104 500 .123 .114 .157 .123 .117 .110 2000 .120 .127 .124 .120 .115 .105 PURI SOI L 0 .068 .075 .110 .068 .069 .069 500 .081 .096 .082 .OBI .085 .085 2000 .073 .184 .129 .073 .167 .195

T ABLE 6. Effect of applica tions of liming mat erials an d monocalciu m phosph at e on th e exchangeable calcium content (as mtlliequivalcnts per 100 gm, of dry soil ) in soils of th e Akaka and Puhi series

CA LC IUM SILICATE LIME APPLIED, P HOSPH ATE lb/ acre APPLIED , A PPL IED, lh /ucre lh/acre ---- 0 5,000 20,000 0 5,000 20,000

AKAKA SOI L 0 1.2 7.7 23.4 1.2 3.5 11.5 500 1.4 9.4 24.2 1.4 3.8 12.2 2000 1.8 8.8 24 .0 1.2 4.3 13.2 PURI SOIL 0 .9 6.6 13.9 .9 1.9 6.7 500 1.1 5.3 11.3 1.1 2.1 6.6 2000 1.3 5.2 10.1 1.3 2.8 7.1

only about half the magnitude of the increase registered for th e lime applications. The calcium content of the Sudan grass tops is given in table 7. The calcium content of tops was increased more by the application of lime than by the application of calcium silicate. The application of phosphate fer­ tilizer gav e a small increase in calcium con tent of the tops in most cases. CALC IUM CAHBONATE A ND CA LC IUMSI LICATE A NDYIELD IN LATOSOLS 19

TABLE 7. Effect of applications of liming materials and monocalcium phosphat e on th e calcium content (as pe rce nt Ca ) of th e tops of Sudan grass grown on Akaka and Puhi soils

C ALCIUM SILICA T E L I ~1E A PJ1LIE D, P HOSPHATE Hi/ nero APP L IED , A P I' LIED, lh /acre Ih/acro 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 0.75 0.D2 1.25 0.75 1.00 0.92 500 .79 .94 1.15 .79 .87 1.00 2000 .8 1 un 1.30 .81 .96 .96 PURl SOIL 0 .75 .96 l.lG .75 .64 .91 500 .75 1.00 1.38 .75 .88 .95 2000 .87 .94 1.3G .87 .8G .8G

The calci um content was determined in th e roots and th e data are pre­ sented in table 8. Th e application of both am endments in creased th e cal­ cium content in the roots; but the application of lime gave a much greater in crease than the app lication of silicat e. A most remarkable and un expected effect was produced by the application of phosphorus on the calcium con­ tent of th e roots of plants grown on th e Puhi soil in that th e application of phosphorus decreased the calcium conce ntration in the roots.

T A BLE 8. E ffect of applications of liming matcrials and monocalcium phosphat e on the calcium conten t (as percent Ca ) of roots of Sudan grass gro wn on Akaka and Puhi soils

CA LC IUM SI LICATE LIl\·IE AI'PLJED, PIIOSP IIATE lb /acre A PPLIEI), APPLIED, lh /acrc llr/n crc 0 5,000 20 ,000 0 5,000 20,000

AKAKA SOIL 0 0.21 0.29 0.5() 0.21 0.24 0.33 500 .22 .28 .61 .22 .29 .35 2000 .22 .33 .G2 .22 .24 .2G PURl SOIL 0 .17 .40 .54 .17 .43 .28 500 .12 .20 .77 .12 .18 .15 2000 .09 .18 .48 .09 .13 .13 20 IlAWAII AGIIICULTUIIA L EXI'E I\IMENT STATION

YIELD VS. PLANT TOP ANALYSIS

PUHI 100 AKAKA 100 • • • Yo Il8 . 75X - 62.50 • •• • • •• • • • 0 ...... J 1&1 5 0 50 • >- • • • • • • • • 0

0 0 .6 0 .80 1.00 .5 0 .7 5 1.00 o/.Co %Co YIELD vs ROOT ANALYSIS 10 0 AKAKA • • PUHI •

0 ...J 50 50 !!! >- •• • • yo 211 .5X -18.0 Y·95.7S-IS6.2X

0 0 .16 .24 .3 2 .4 0 .05 .10 .30 .5 0 % Co % CO YIELD vs SOIL ANALYSIS

100 100 AKAKA PUHI • • , • • • • • • • 0 ...J 1&1 50 50 • >- • • , . .. • • '" y. 24.2+ 3.3X 0 0 2 4 6 8 10 12 14 2 4 6 8 ExCo ExCa F I GUH E 2. Relationships between yield and calcium contents of plant material and soil extracts. CA LCIUM CA HIlONATE AND CA LC IUMSI LI CATE AND YIELD IN LATOSOLS 21

T he ana lysis of th e tops reveals a similar situa tion in both soils in that the uptake du e to lime was con siderably gr eater than that du e to calcium silicate. The analysis of variance ( table 2 ) confirms that an over-all increase in calcium uptake occurs with increas es in phosphorus levels. Wh en th e calcium content of soil, roots, or tops is compared with th e yield ( fig. 2 ), th e Akaka series shows a positi ve correlation in all cases; namely, yield vs, calcium content of plant tops, yield vs. calcium content of roots, and yield vs. exchange able calcium in soil. This would indi cat e a shortage of calcium by the plant in untreated soils but for th e fact that th e Pu hi results are within th e sam e ran ge of calcium values as th e Akaka seri es; th erefore, it is more likely that calcium is ac ting upon another fac­ tor which is in turn affecting yield. In contrast, th ere is no positi ve correla­ tion between yield and calcium status of plants or soils in the Puhi experi­ ments; and a negative correlation is evide nt between yield and calcium content of th e plant roo ts. Aluminum: Th e amount of al uminum which can be extrac ted from th e soil is given in table 9. Th e data show a red uction in extractable aluminum occurred through the addition of lime or calcium silicate and also up on the application of monocalcium phosphate. The Akak a soil contains consider­ ab ly more extra ctable aluminum than th e Puhi soil.

TAIlLE 8. Effect of applications of limin g materials and monocalcium ph osph ate on the am ount of extractable aluminum ( as millicquivalcnt s per 100 gm. of dr y soil) in soils of th e Akaka and Puhi series

CA LCIUM SILICATE LIME A PP LIED, PIIOSPIIAT E lh/ acre APPL IE D, APPLIED , Ib/ aere lh/ncre o 5,000 20 ,000 ° 5,000 20,000 AKAKA SOIL 0 18.5 12.0 5.4 18.5 15.2 7.2 500 16.8 11.7 5.5 16.8 13.4 6.7 2000 15.2 10.2 4.7 15.2 12.1 5.6 l' UHI SOIL 0 3.1 1.0 .4 3. 1 UJ .5 500 3.5 .8 .4 3.5 1.4 .4 2000 2.5 .n .4 2.5 1.5 .4

In spite of th e large vari ation in th e root analysis values ( table 10 ), it appears that lime and calcium silicate reduced th e aluminum content in th e roo ts of plants grown on soils of the Akaka series, and that mono cal- 22 H AWAII AG IIICULT U HA L EX PElllMENT STAT ION

TA BL E 10. ER ect of applica tions of liming materials and mon ocalcium ph osphate on th e aluminum content (as ppm dry matter ) of roo ts of Suda n grass grown on Akaka and Pllhi soils

CALCIUM SILICATE L Il\ (E A PPLIED , P IJOS P IIATE lh / ncre APPLIED, A PPLIE D, lb / acrc Ih/ acre ° 5,000 20,000 ° 5,000 20,000 AKAKA SOI L 3470 1670 1400 3470 2030 17S0 500° 2940 1780 1370 2940 1070 9S0 :2000 2110 2080 1330 2110 2130 1540 I'UHl SOIL 0 1610 9,50 2600 1610 1260 3000 500 2950 2870 2560 2950 2760 2200 2000 4080 4370 1000 4080 4540 5960

cium phosphate increased th e aluminum conte nt of roots in th e Puhi seri es. As pr eviou sly noted, the increase of aluminum content in th e Puhi series was po ssib ly due to conta mination by soil particles. In the pl ant tops, calciurn silicate suppressed aluminum uptake; but

lim e appear ed to increase uptake at th e L 2 level in th e Puhi series ( table 11 ). The differen ces were not large.

T AB L E 11. Effect of applica tions of liming mater ials an d monocalciu m phospha te on th e al uminum content ( as ppm dry mat ter ) of tops of Sud an grass ' grown on Akaka and Puhi soils

CA LCIUM S ILICATE L U\[EA P PL IE D, P HOSPHATE lh/ ucrc APPLIED, A PP l. IED, lh / ucr e lh/acrc ------° 5,000 20,000 0 5,000 20,000 AKAKA SOIL 0 136 118 132 136 125 113 500 138 121 137 138 101 119 2000 148 129 167 148 III 102 I'UHl SO IL 0 115 121 199 115 ~J6 90 500 130 149 176 130 104 105 2000 143 151 181 143 137 99 CALCIUM CAHBONATE A ND CALCIUM SILICATE AND YIELD IN LATOSOLS 23

Yield relationships presented in figur e 3 show that in th e Akaka series a reduction in aluminum level in th e soil, roots, and tops was accompanied by an increase in yield; in th e Puhi ser ies th ere was no relationship with yield except in th e aluminum content of th e roots. Figure 3A shows that as th e aluminum content of th e root increased th e phosphorus content increased but th e calcium content decreas ed . Th ese correlations occurred for both soils. pl]: As shown in data presented in tab le 12, th e pH of th e soil was increased to a greater extent by lime than by calcium silicate. Th e gen­ eral increase was hi gher in th e Puhi soils than in th e Akaka soils, reflect­ ing th e difference between th eir buffering capacitie s. Th e reaction of th e soil was related to excha ngeable calcium and to yield (fig . 4) .

TABLE 12. Effect of applicati ons of liming materials and monocalcium phosph ate on th e pH of th e soils of th e Akak a amI Pllhi series

CALCIUMSILICA T E LI ~f E APPLIED, P HOSPHATE Ih/acr c APPL IE D, A PPLIED, lh / acre lh / ucre 0 5,000 20,000 0 5,000 20 ,000

AKAKA SOI L 0 4.5 5.5 7.0 4.5 4.9 5.4 500 4.6 5.6 6.8 4.6 5.0 5.5 2000 4.6 5.6 7.0 4.6 5.0 5.4 r UHI SOIL 0 4.5 5.9 7.4 4.5 4.9 5.9 500 4.5 5.5 7.4 4.5 4.9 ,'5 .9 2000 4.5 5.9 7.4 4.5 4.9 5.8

Cation Exchange Capacity : Data presented in figure 5 show th e effect of aluminum on cation excha nge capacity, and indicate a re duction in aluminum was accompanied by an increase in cation exchange capacity. Magistad (1928) had previously poi nt ed out this phenomenon. It is also of int erest to note that in th e Akaka soil th ere appeared to be a relation­ ship between yield and cation exchange capacity; this relationship is shown in figur e 6. No such relationship existe d in the Puhi soils. Exchangeable Calcium and Extractable Aluminum Relationships: The data presented in figur e 7 indicate a definite relationship existe d between exchangeable calcium and extractable aluminum in both th e Akaka and Puhi soils. This relationship appeared to be associated with yields in th e case of th e Akaka soils, but not in th e Puhi soils. 24 IIAWAU A GHlC ULTUIlAL EXPElIIMENT STATION

YIELD vs PLANT TOP ANALYSIS

AI

o L...__---L ...L ---' OL...-----'------'-----' 10 0 120 14 0 160 70 100 130 160 ppm AI ppm AI YIELD vs ROOT ANALYSIS 100 AKAKA 10 0 PUHI • • • 0 / •

Ya74.3 - .0 15X .~ Q ~ : kl 50 ~ 5 0~. ':.:~ ): ...... ~. • .."", y. 37. 4 + .0094X OL..._...L-_--L_-L_--'__-'------' oL..._...L-_-L_-..L_----lL-_::_::_' o 2000 4000 o 10 0 0 3000 500 0 pp m AI ppm AI YIEL D vs SOI L ANALYSIS

10 0 100 AI- • • •• ..~ •

OL..._.1-_--L_-'-_--'_---' 10 15 20 25 o 2 3 ExAI ExAI FIGUIlE 3. Rela tions hip s between yield and aluminum contents of plan t material and soil extracts. CA LC IU M CA RB ONATE AND CA LC IUM SI LICATE ANDYIELD IN LATOSOLS 25

ROOT RELATIONSHIPS

ppm AI vs %P AKAKA PUHI 4000 6000 • • • • 5000 • • •/ 3 0 0 0 4000

lOooL. I .0 9 0 .100 .110 .120 .130 .14 0 .150 .050 .10 0 .150 ·/.P "loP

ppm AI vs % CO AK AKA PUHI 3500 • • 6000 • • • 3000 Y=4BBO -10500X 5000

~ • • e 2500 4000 Y=4721 -B9BOX 0. 0. • • • •• • 2 0 0 0 • 3000 ••• • ••• • • 150 0 • 2000 • •• 1000 .---l 1000 • -.1• .15 .2 0 .30 .4 0 0 .10 .2 0 .30 <4 0 .50 % Co % Co

FIGUR E 3A. Helat ionships between aluminum content of roo ts and phosphorus conten t of roots, and also be twee n aluminum and calcium. 26 HAWAII AG lIlCULTUHA L EXPElIlMENT STATION

Yield vs. Soil Analysis

100 AKAKA • • • 0 ..J 50 IaI • >- • :------:• , Y-3I.SX-IIS.3

01 I I 4.5 5.0 5.5 pH

PUHI 100 • • ••• • • • • 0 ..J IaI 50 • >- • • •

0~---_.1...-_---J 4.0 5.0 6.0 pH

F IGUHE 4. Hclutionships betw een yield an d plI of the soil. CALCIUM CAHBONATE AND CA LCIUM SILI CAT E AND YIELD IN LATOSOLS 27

CEC vs ppm AI

AKAKA 170

• y. 165.2 - 1.95X

160

150 o • ILl o •• • • • 140 • • •

130 •

120 L-_--L_--Jl-..._...L-_--L__.L..-_-L._---I__.L.-_--J 4 86 1210 1614 18 20 22

ppm AI

FIGUHE 5. Relationship betw een cation exchange capacity and aluminum content of the soil extract. 28 HAWAII AGIUCULTUHAL EXPEIUMENT STATION

100 AK AKA • •• 0 • ..J 1&1 ~ • • ... • y • .67X - 51.65 0 120 140 160 180 CEC

100 PUHI • • , • • • •• • 0 ..J • 1&1 50 ~ I • • J 43 45 47 49 51 53 CEC

F IGUHE 6. Relationships between yield and cation exchange capacity of the soil. CALC IU M CARBONATE AND CA LCIUM SILICA TE AND YIELD IN LATOSOLS 29 Ext. AI vs. Exc. Ca in Soil

AKAKA

y a I8.85 - 1. 0 2X 10

c o 6 )( -ILl

2

5 10 15 20 Exc. AI

7.0 PUHI

Ys6.7-2.07X 5.0

c (.) ..: )( ILl

1.0

1.0 2.0 3.0 4.0 Exc. AI

F IGURE 7. Relationships be tween extractable aluminum and exchangeable calcium in th e soil. 30 HAWAII AGHICULTUHAL E XPE lUMENT STATION

Results of Correlation Coefficients: Tables 13 and 14 present the cor­ relation coefficients which have been calculated from th e relationship of yields to various soil and plant factors and the relationships between vari-

TABLE 13. Correlation coefficients calcul at ed from th e relationships between dry matter yield of Sudan grass and various factors

SI GNIF-C O E F F IC IENT FA CT o n SOIL r I CA N C E OF D ETEHMINATION

Yield vs. In Plant Tops % phosphorus Akaka + .03 N.S. Lo g % ph osphorus I'uhi +.87 ** 75 .7% %calcium Akaka + .66 ** 43 .6% % calcium I'uhi +.35 N .S. ppm aluminum Akaka - .48 * 23.0% ppm aluminum Puhi +.38 N .S. In Plant Roots % phosphorus Akaka +..56 * 31.4% Lo g % phosphorus Puhi + .77 ** 59 .3% % calcium Akaka +.56 * 31.4% % calc ium Puhi - .7 1 ** 50.4% ppm aluminum Akak a - .64 ** 41.0 % ppm alum inum Puhi + .70 ** 49.0% In the Soil ppm phosphorus Akaka + ,(->3 *~ , 39.7% Lo g ppm phosphorus l'uhi +JJ! ** 82.8% E xchangcablc calci um Akaka + .78 * :~: 60.8 % Exch angeable calcium Puhi +.11 N.S. pH Akaka + .70 ** 49.0% pH l'uhi + ,(J3 N.S. Extractable aluminum Akak a - .86 ** 74 .0% E xtractable aluminum l'uhi - .26 N.S. Ca lion excha nge capacity Akaka + .47 N.S. 22. 1% Ca tion exchange capacity l'uhi +.23 N.S.

** Si g nifica n t at 1% l ev el. * Sign iflcan t a t 5% level. N.S. N ot s ign ifican t. CALCIUM CARDONATE AND CALCIUM SIL ICATE A ND YIELD I N LATOSOLS 31

TADLE 14. Co rrelation cocfficicnts calculate d from relationships within soil ana lysis values and root analysis va lues

COEFF IC IENT FACTOH a vs. FACTOIl b SOIL SIGNIFICANCE OF llET E IIl\II N AT IQ N

Roots Alumi num vs. calcium Akaka -.64 ** 41.0% Aluminum vs. calcium Pu hi - .55 * 27 .8% Aluminum vs. phosphorus Akaka + .75 ** .56.2% Aluminum vs. phosp horus l'uhi +.60 * 36.0% Soil Aluminum vs. calci um Akaka - .95 ** 90 .2% Aluminum vs. ca lcium Puhi - .91 ** 82 .8% Aluminum vs. phosphorus Akaka - .28 N.S. Aluminum vs. p hosphorus l'uhi - .22 N.S. . Aluminum vs. CEC Aka ka -.61 ** 37.2% Alum inum vs. CEC 1'1Ihi - .4,5 N.S.

** S ign ificant a t 1% lev el. * Si gnifi cant at 5% l evel. N .S. Not sign ifican t.

ous fac tors in soil and root analysis. Th ese data reveal that there was a significant relationship between yields and the log percent phosphorus in p lant tops grown on Pu hi soil, and also between yield an d calcium content of plant tops grown on Akaka soil. In addition, they indicate significant relationships between yield an d the calcium, aluminum , an d phosphorus content of roo ts of plants grown on both soils. In the Akaka soil, th ere also were significant relations hips between yield and the phosphorus, exchangeable calcium, soil reaction, and extractable alumi num of th e soil; but, in th e Puh i soil, only the relationship between yield and phosphorus content was sign ificant. In both soils, there was a significant negative correlation between the aluminum and the calcium conten t of the roots, and a sign ificant positive correlation between the aluminum and the phosphoru s content of the roots. Also, in both soils, the re lations hip between alu minum and calcium content of the soil was highl y significant. 32 HAWAII AG lIICULTURAL EXPEIUMENTST ATION

Leachate Studies Although the results were not sta tistically an alyzed, it is obvious from tabl e 15 th at the aluminum content of the nil treatment in the Akaka soil was extremely high, and that thi s conce ntration was reduced by applica­ tions of lime and calcium silicate and by monocalcium phosphate. Hester (1935) stated that plan t growth was dir ectly correlated with the appear­ ance of aluminum in drainage wat ers. In the case of the Puhi soil, the result s were gene rally low ; however, monocalcium phosphate increased the aluminum content in the leachate at the So and Lolevels, and th is wa s accompanied, appa rently, by a dr asti c lowering of th e pH of th e leachate solution.

T ABLE 15. Effect of ap pl ications of liming materi als and monocalcium phosphat e on th e aluminum conte nt (in ppm) of th e second Ieachat es

CA LCIU M SILICATE LI l\[E APPL IE D, P HOSPIIATE lh / acre APPLIED, APPL IED, lh/ acre lh/ acre 0 5,000 20,000 0 5,000 20,000

AKAKA SOI L 0 5.1 0.3 0.3 5.1 0.3 0.4 500 1.4 .3 .5 1.4 .4 .5 2000 1.4 .5 .5 1.4 .6 .5 PURl SOIL 0 .4 .3 .3 .4 .9 .5 500 3.1 .9 .2 3. 1 1.7 .3 2000 2.7 .3 .2 2.7 .4 .4

The graph presented in figure 8 shows the relationship between alumi­ num content and pH and illustrates clearl y the reduction in soluble alumi­ num whi ch occurred as the pH increased . At approximately pH 5.6, th e aluminum content remained constant with increasing pH. It was com­ pletely soluble at pH 3.5. The activity of aluminum in th e 3.5 to 5.6 range corresponde d to the activity of aluminum on decreasing the pH of an AI203(P205)'H20 colloidal complex ( Miller, 1956). Ma gistad (1925 ) pointed out that wh en the acidity became grea ter than pH 5, the aluminum solubility began to increase until pH 4.5 was reached, at which point it then proceed ed to increase rapidly.

Although the concentration of phosphorus was variable, the L 1 level in th e Puhi soil increased th e phosphorus content wh en phosphorus was CALCIUM CARBONATE AND CA LC IU M SI LI CATE A ND YIELD IN LATOSOLS 33 2nd LEACHATE - BOTH PUHI a AKAKA ppm AI vs pH

5 •

4

3 « 2

3 4 567 8 pH (2nd Leachate 1

FIGUIl E 8. Helationship between aluminum content and plI of th e seco nd leachat e. 34 HAWAIl A GHlCULT UlIAL EXPEHlMENT STA nON added; this occurred in both th e first and second leachates (tables 16, 17).

However, at th e L 2 level, th e increase was mu ch smaller, due probably to th e formation of tr icalcium phosphate at thi s level. The uptake in th e plant tops reflected th is increase.

T ABLE 16. Ellcct of applicati ons of liming ma tc rials and monoc nlcium phosphate on th e p hosphorus conte nt (in ppm) of th c first lcnchates

CALCIUMS ILICATE LIME A PP LIED, P HO SP HATE lh/ ucre APP LI E D, A PPLIE I), lh / ucrc lh / ucro 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 0.09 0.07 0.09 0.09 0,()3 0.02 500 .07 .05 .10 .07 .05 .16 2000 .03 .26 .16 .03 .05 .13 PURl SOIL 0 .08 .13 .33 .08 .05 .10 500 .08 .27 .26 .08 .05 .10 2000 .08 1.42 .41 .08 .06 .63

T ABLE 17. Effect of applications of lim ing ma tc rials ami monocalcium phosphat e on th e phosphoru s con ten t (in ppm) of th c second lcachatcs .

CA LC IUMSILICATE L Il\-fE A PPLIED, PHOSPHATE Ih/ acrc A PPLIED, APPLIED, lh /acre lh / acre 0 5,000 20,000 0 5,000 20,000

AKAKA SOIL 0 0.05 0.08 0.05 0.05 0.05 0,()7 500 .06 .11 .09 .06 .05 .17 2000 .06 .14 .09 .06 .11 .21 PUHI SOIL 0 .06 .05 .08 .06 .14 .18 500 .06 .22 .08 .06 .05 .14 2000 .08 .65 .11 .08 .08 .09 CALCIUM CAHllONATE AND CALCIUM SILICATE AND YIELD IN LATOSOLS 35

DISCUSSION A considerable amount of data was collected during this investi gation; however, it should be kept in mind that the main objectiv e of this study was to explain differences in response to lime and calcium silicate on Akaka soil and on Puhi soil. It has been shown from the yield results that both lime and calcium silicate increased yield to the same extent in the Akaka soil and that mono­ calcium ph osphat e also increased yield and in a linear manner. On th e Puhi soil, only th e highest applica tion level of calcium silicate appeared to in crease yield, and then but slightly. The main increase in yield came from the use of monocalcium phosphate. The reduction in yield caused by the highest lime application has been omitted from thi s discussion. Several hypotheses were outlined at th e end of th e for egoin g litera ture review section of this bulletin; th ese ar e now analyzed, using the evidence cited above. 1. a. The breakdown of organic matter (if any ) did not release soluble aluminum to the drainage waters. This is sho wn in the leaching stu dies. b. Phosphorus was released by lime or calcium silicate only whe n monocalcium phospha te was adde d. 2. Although calcium upt ake cor rela ted with yield in the Akaka soil series, the ra nge of calcium values was not lower tha n th e Pu hi series, which showed no relationship with yield. Therefore, it is likely that calcium was acting with anoth er factor which was, in turn, affectin g yiel d and was not a limiting fac tor in itself. Evidence shows that thi s factor may ha ve been alu minum. Men­ chikovsky and Puffeles ( 1938) reached a similar conclusion. 3.Aluminum is certai nly a major factor in the Akaka soil but appears to be of littl e importance in the Puhi soil. Aluminum can be negatively correlated with yield in the top s, roots, and soil in th e Akaka series, but no correlation is indicated in the Puhi studies. Leachate studies also showed extremely high con­ centrations of aluminum in the untreated pots in th e Akaka series. It appears likely that aluminum acts as a "toxic" fa ctor in th e Akaka soil and is reduced by eithe r high calcium ion con­ centration, high pH, or high phosphorus content, or by combina­ tions of these three conditions. King (1961) has shown that upon ad ding phosphorus, high amounts of aluminum phosphate ar e form ed in this soil type, wh ereas relatively smaller amounts ar e formed in a soil similar to the Puhi soil. H artwell and Pember (1918) , and others, also foun d that the addition of phosphate reduces "active" aluminum . They sta ted : "The practical advan- 36 H AWAII A GHI CULTUHAL E X P E HI M E NT STATION

tage of phosphating and limin g ma y often prove to be du e to the precipitation of active aluminum ." Reasons for the action of alum inum in reducing yield ar e purely speculative. Relation­ ships between aluminum and phosphorus in the roots of plants grown on Akaka soil indi cate the possibility that aluminum phos­ phate is form ed in the root. Pierre and Stuart ( 1933), and others, have placed importance on this occurrence, which is said to prevent phosphorus uptake by the plant tops; however, phos­ phorus was ad equate in the plant tops of the Akaka series.It is more likely then that aluminum affects the metabolic functions of the plant cell at the aluminum con centrations found in Akaka soils. Evidence for this supposition is found in the work of Huth Addoms ( 1927 ), who examined the root hair cells of the wheat plant while imm ersing them in salt solutions. She found that

aluminum and zin c penetrated the cell rapidly and I produced a severe flocculation of the protoplasm ; coagulation finally became irreversible and death of the cell resulted . 4. T here is evidence (analysis of the leachat es ) that added ph os­ phorus is released to the soil solution by the addition of lime or calcium silicate. With the highest applica tion of calcium silicate, th e second leachate of the Puhi seri es at the Po and PI levels showed an increase in soluble phosphorus. This increase in solu­ ble phosphorus was reflect ed in an increas e in yield; it wa s not evident in either plant uptake or soil tests . Inasmuch as Puhi soil appe ars to lack the ability to supply adequate phosphorus to th e p lant, an y increase in available phosphorus shou ld therefore cause an increase in yield. This is not the case, however, in the Akak a soil, where its phosphorus supply to the plant appears adequate an d would not of itself be limiting to growth; here, monocalcium phospha te ma y be acting indirectly on the yield by red ucing aluminum and thereby causing an increase in yield. 5. On ly th e effects of phosphorus, calcium, and aluminum have been inves tiga ted in this study; and it is rea lized tha t other fac ­ tors could be involved and that there is much mor e work to be done in this field. For example, manganese may be present in toxic concentrations and may be reduced by the action of liming ma teria ls; or, molybdenum may b e made more available.

CONCLU SION In a Hydrol Humic La tosol, both calcium carbonate and calcium silica te appear to increase the yield of Sudan grass, provided the plI remains be low approximately 6.8; above this value, yield is depressed. Increased yield is CALCIUM CA RBONATE AN D CA LCIUM SILICATE AN D YI E LD IN LATOSOLS 3 7 probabl y du e to the reduction of "toxic" aluminum brought about by th e action of calcium ions and increasing pH. In a Humic Ferr ug inous Latosol, lime do es not increase yield but depresses it at high pH values . Calcium silicate slightly increases yield at high er values; such increase is probably du e to increased availabl e phos­ phorus and not to a decreas e in th e "active" aluminum. Aluminum do es not appear to be a toxic fac tor in thi s soil. Monocalcium phosph at e increases yield in both cases-in th e H ydrol Humic Latosol by re ducing "toxic" aluminum, and in th e Humic Ferru­ ginous Latoso l by supplying phosphorus as a nutrient.

LITERATURE CITED (1) A DI)OMS, B UTII M. 1 9 2 7 . TOXICITY AS EVIDENCED BY CHANGES I NT HE P IlOTOPLASMIC ST IlU CTU RE OF IIOOT IIAlIIS OF WHEAT . Amer. J . Bot. 14: 1 4 7 -15 6. (2) Avnzs, A. S. 1961. P ersonal commu nication. H a w a i ia n S ugar Pla nte r s ' Assoc., H onolulu. (3 ) _ __ and H. E. H AGIIIAII A . 1 9 5 5 . SOI L ANALYSES AS IND EXES OF NUT lII ENT AVAILAIlILITY. H a w a iian P lant ers' B e e . 55: 113 -12 5 . ( 4 ) B EAT ER , B . E. 1 9 4 5. THE VA LUE OF PIlELIMING, PRIMAlIILY AS A JlI EA NS OF IM P HOVIN G THE ABSOHPTION OF PIIOSP IIOIlUS BY PLANTS. Soil S ci. 60: 337-352. (5) BLACK , C. A . 1 9 5 7 . SOI L-PLANT I1ELATIONS.J ohn Wi ley a n d Sons , Inc., N cw York. (6) B OUL DI N , D. R ., a n d C . A . B LACK. 1 9 5 4 . FEIITILlZEII EVALUATION. IV. USE OF 1''' LABELED F E HTI LIZ EIl S. Soil Sci. Soc. A m e r. P roc. 24: 491 . ( 7) CHENEHY, E. M . 194 8 . TII IOG LYCOLLIC ACID AS AN IN II IHlTOR Fall m o x INT HE CO LOHIMETIIIC DETEIlMINATION OF A LU M INUM BY MEANS OF A LUMINON. The Analy st 73: 5 0 1-502. (8) C HEIlNOV, V. A ., and N . L. BELYAEVA. 1 946 . T HE NATUIlE OF SOI L ACI DITY. P e dology: 593-6 03. ( R.e. ) ( 9 ) C HlZIIEVSKH, M . G., a n d M . A . KOIlOVKIN . 1 9 5 8 . T HE EFFECTIVEN ESS OF LiMING ACID SOILS CON T AIN IN G DIFF ERENT AMOUNTS OF AVAILAB LE A LUMINUM. I z v . tim iryazev, s .-kh. Akad, 3: 1 3 7 -15 2 . ( R .e .) (10 ) CLEMENTS, H. F. 1 9 6 2 . T HE COIlAL STONE-PHOSPHATE EX PElIIJlIENTS ON T ilE HILO AND H AMAl>."UA COASTS . Proc. H a w aiian S u gar T e c h . 2 0th A nn. M e e ting, H o n olulu. Pp. 77-105. ( 1l) COLEMAN, N .T., E. J. K AM P IIAT H , a nd S . B. W EED. 195 8 . LIM ING. A d vanc. Agron. 10: 475 - 5 2 2 . (12 ) CON N E ll , S. D. 1 9 2 1. Li M ING IN ITS RELATION T O INJUHIOUS INOIlGANIC COMPOUNDS I N THE SOI L . J. Ame r. Soc . A gron. 1 3 : 113. (1 3) D UTIHE, D . W ., a n d C . L. C . B OURNE. 1 9 3 9. AC IDITY AND " AC TI VE" ALUMINA IN BRITISH GUIANA SUGA R- CANE SOI LS . A gric. J. B r itish Guiana 10: 112 -12 3 . (1 4) ENGELS, O. 1 9 36. T HE INFLUENCE OF LIMING ON THE SOLUBILITY OF PHOSP HORIC ACID IN ACID SOI LS . Z. P flErn1ih r . Dung . 43: 350-356. ( G. ) HAWAIl AG Hl CULTUHAL EXPElUMENT STATION

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( 33 ) Low, P . F., a n d C. A . BLACK . ] 948. PHOSPHATE INDUCED DECOMPOSITION OF KAOLINI T E . S oil S ci. Soc. Amer. Proc . ] 2: 180-184. ( 34 ) MAcINTlIlE, W . II. , S . H. WINTEHB EH G, II. W. D UNHAM, et al. 1946 . VAlIlANCE IN TIlE CAHIlONATION OF C lm TA IN "GLASSy " AND CHYSTAL LINE CA LCIUM SILICATE M ATElIlALS IN SOIL. S o il S c i. 61 : 295- 311. ( 35 ) , , __, ct al. 1947. PHOSPHATE MIGRATION I N L1I\IESTONED ANDDOLOMIT ED SOI LS AS IlEG­ IST EII ED BY PLANT HESPONSE . Soil S ci. Soc. Amcr. Proc, 12: 359 . (36) MAGISTAD, O. C. HJ25. T ilE ALUMINUM CONTENT OF TIlE SOIL SOLU T ION AND ITS HELATION TO SO il, HEACTION AND P LA NT GHOW TII. S oil Sci. 20: 181- 225. ( 37) 1928. T HE ACTION OF A LUl\lINON, FEHHOUS AND FElUliC m ON , AND MANGANESE IN IlASE-FXCIlANGE HEACTIONS . Arizona Agri c, Exp . S t a . T e ch. Bull. 18. Pp. 44.5-4 63. (38) M ATE , F., a n d F . MOl,N AH . 1956. EX PEIIIMENTS ON P IlOSPIlOHUS FIXATION I N M EAIJOW SOI LS . Agrokem. Talajt. 5 : 165- 170. ( H u.r.e .g.) ( 39 ) M AT T SO N , S ., E. G . WILLIAMS, and E. B AHKO F F . 1950 . PHOSPHATE HELATION SIIIPS OF SOIL AND PLAN T. 3. F OIl M S OF PINT IlE IlIl AN NAI.T LIMED AND UN LIMED P ODZOL SEmES. K gl. La ntbrIIogsk. An. 17: 107-120. (E.) (40) M CG EOHGE , W. T . 1924. T IlE IN FLUENCE OFSILICA, LIME, AND SOI L Il EACTION ON TIlE AVAI LA DI LITY OF PIIOSPHATES I N HIGIlLY F EHH UGINO US SOI LS . Soil S ci. 17: 463. (41) MENCIllKOVSKY, F., and M . l ) UFF E LES . 1938. T HE II ELATION OF EXCHANGEAII LE CATIONS TO 'ACTIVE' ALU I\I1N IUI\[ I N SOI L. S oil S c i. 45: 25--28 . ( 42) MIl,LER , J . 1956. P ersonal c o m m u n ica t io n. ( 43) MITSCHERLICH, E. A . 1947. EX PElIlMENTS ON TIlE FIXATION OF PHOSPIIOHIC AC ID BY APPLICATIONS OF CA LCIUM CAH IlONATE. Pflanz. Dung . 39: 1-9. ( G.) (44) MONTEI TH,N . IT.. et al. 1958. U n p u b lished r eport. Th e Colonial Sug ar R efining C ompany , Ltd. S ydney. ( 45 ) _ _ , et al. 1959 . Unpublish ed r eport. The Colonial Sug a r R efining C o m p a n y, Ltd. Sydne y. ( 46 ) MOSCHLEH , W . W., G .D . J ONES, and G. W . Tnoxrxs. 1960. LIME AND SOI L ACIDIT Y EFFECTS ON A LFALFA GHOWTIl I NA R ED -YELLOW P ODZOL SOI L . S oil S c i . S o c . Ame r. Proc, 24: 507. (47) M ULDER, E. G., a n d F . C . GElUIETSEN. 1952. SOIL MANGA NESE IN RELATION TO PLANT GHOWTIT. Advanc. A gron. Ac­ ademic Press , N ew York. P. 222. ( 48 ) N ELSON , R. E. 1958. P ers o n al c o m m u n icat io n w ith Dr. J . C . M oomaw. H awaii A gric. Exp. Sta ., Hono lulu. ( 49) P EIVE, Y A. V. 1939 . rIlOSPIIOmTING AND LIMING OF SOI LS CON TAIN IN G MOllILE ALUMINIUM FOR TIlEGHOWT Il OF FLAX . L en i Konoplia 2 : 36-40. ( R.) ( 50 ) P ETERBUH GSKY, A . V. 1941. M OllILiTY OF A LU M IN IU M AND T HE EFFECT OF LIMING F LAX SOILS. Dokl. Akad. s.ikh. Nauk 10: 33-37. ( R.) ( 51 ) PIEIUIE, W . H., and A . D. STUART. 1933 . SOLU BLE ALUMINUM STUDIES. IV . TIlEE FF ECTS OF PIIOSPHORUS IN REDUC­ I NG TIlE DETHIMENT AL EFFECTS OF SOI L ACIDITY ON PLANT GHOW'll!. Soil S ci. 36 : 211-227. UNIVERSITY OF HAWAII COLLEGE OF TROPICAL AGRICULTURE HAWAII AGRICULTURAL EXPERIMENT STATION HONOLULU, HAWAII

THOMAS H. HAMILTON President of the University MORTON M. ROSENBERG Dean of the College and Director of the Experiment Station G. DONALD SHERMAN Associate Director of the Experiment Station