Yield, Quality, and Sucrose Recovery from Sugarbeet Root and Crown1 R. c. Z I ELKE2 Receivedfor publication May 15, 1973 Since the advent of mechanical harvesting in the late 1940's, all increasing amount ofcrown tissue has been processed by the factories. The introduction of crowns into factory processes has long been considered undesirable because they contain higher concentrations of impurities than roots and, consequently, further reduce crystallization of sucrose from thejuice (6,12)3. Data compiled from the late 1800's by Stehlik (14) established that the crown con tained a concentration of sucrose only somewhat less than that of the root. It would be desirable if the sucrose in the crown could be crystallized at a net gain to factory operations instead of losing it to molasses production. Early investigators lacked formulae and analyses to determine whether sucrose could be recove red if crowns were processed. Now formulae are available for calculating sucrose recovery from simulated factory operations (2 , 15) and improvements have been made in the laboratory analyses of certain juice impurities. The objectives of these studies were to ascertain the relationship between root and crown in yield sucrose content, juice purity, and recovery ofsucrose. Nitrogen fertiliza tion, harvest dates, plant popula­ tions, and varietal differences wen.: incorporated into the experiments because they affect sucrose recovery. Methods and Materials 1967 field experiment A factorial split-split-plot design with six replications wa s arranged with two N levels serving as the main-unit treatment. The 24:lb/A rate of N was supplied by using 200 Ib/A of 12-6-6 4 as a row fertilizer at planting time. The 150-lb rate was the basic rate plus 126 Ib of addi­ tional N applied as ammonium nitrate on the soil surface at thinning time and cultivated into the soil. Additional amounts of P and K were uniformly applied before planting according to soil test recommenda­ tions. Beets were thinned to a uniform 120 plants per 100 feet o frow. 'Cooperative investigation by the; Agricultural Research Service, U. S. Department of Agricul­ ture and the Michigan Agricultural Experiment Station. Approved for publication as Journal article #6165, Michigan Agricultural Experiment Station. 'Research Agronomist, Agricultural Research Service, U. S. Department of Agr;culture, East Lansing. Michigan 48823 3i\umbers in parentheses refer LO literature cited. 'P alld K expressed on ox id e basis. VOL. 17, No.4, OCTOBL R 1973 333 Three cultivars of sugarbeet (Beta vulgaris L.), composing the subunit treatment, were planted on May 2 near Sebewaing, \1ichigan. The cultivars were 'SP63194-0' (No. 1 in the tables), an open-pol­ linated monogerm; '02 clone' (r\o. 2), an open-pollinated multigerm; and 'CS H20' (No.3), a commercial monogerm hybrid. Each plot was four rows wide (28-inch rows) and 76 feet long. One interior-posi­ tioned row was randomly divided into four sections for harvest. A 13-foot sample of beets was harvested from each culrivar on Sept. 14, Oct. 5, Oct. 24, and Nov. 7 for yield and laboratory analyses. 1968 f ield experiment A factorial design involving two"\: levels, two in-row spacings of beets, two cultivars, and two harvest dates was used with six replica­ tions. Nitrogen levels were arranged as a split-plot and the remaining eight treatment combinations were randomly distributed within each split-plot level. Each treatment was 18 feet long and six rows wide (28-inch rows). Two rates of ,30 and 150 lbl A, were established. Row fertilizer (500 lbl A of6-24-12)4 supplied the basic rate. An additional 120 lb ofN was applied as in 1967 to provide the 150-lb rate. Because the P and K soil test readings were high, no additional amounts of these two nutrients were applied. Row fertilizer was placed 2 to 3 inches below the seed both years. Two in-row spacings of beets were esta blished to represent differences in commercial beet stands. At harvest, the narrow plant spacing averaged 9.8 inches (122 plants per 100 feet ofrow) and the wide spacing 15.4 inches (78 plants). Two hybrid cultivars planted on April 30 near Saginaw, Michigan used the Fl monogerm female SL(l29x 133)cms. 'SP6322-0' was the pollinator for cultivar No. 3 (US H20) and 02 clone for cultivar No.4. The harvest dates were Se pt. 23 and Oct. 21 . Seventeen feet of row were harvested from each plot with the wide in-row spaEing and 13.5 feet from each with narrow spacing to provide] 4 to 16 beets for yield and laboratory analyses. Laboratory analyses and techniques Beets without leaf blades and petioles were delivered to the laboratory within 4 hours after harvesting. The crowns were prepared as suggested by Jorritsma and Oldfield (8) , i.e., petiole stubs and leaf buds were removed with a knife to expose the white crown tissue. The beets were washed free of adhering soil and air-dried briefly. Crowns were separated from the roots at the lowest original leaf (7) and both parts weighed. Brei samples were collected by cutting each root in half 334 JOURNA L OF THJ:: A. S. S. B. T. with a single-bladed saw (16-in. diam.). Crowns were quartered with the same saw to obtain sufficient brei. Juice samples were obtained, quickly frozen in a dry ice-alcohol bath, and later clarified and analyzed according to the DFS method (3). Apparent sucrose contents of brei and clarified juice were deter­ mined polarimetrically. Analyses for reducing sugars and raffinose were made to correct apparent sucrose, clear juice purity (eJP), and recoverable sucrose as outlined in (4, 16). Results and Discussion Yield and proportions of root and crown Root yields (exclusive ofcrown) were significantly different within the harvest date and cultivar treatments but did not differ for beet spacings or nitrogen levels (Table 1) . The lack of response in root yield to the high N levels reported in the last decade (1, 10, 11, 13) may be attributed to the greater residual N levels and total fertility now found in soils of beet-growing areas of Michigan and Ohio. Crowns accounted for 22% ofthe total yield harvested in 1967 and 17% in 1968. These percentages cannot be compared with commercial factory crown tare values because the roots in our tests wer-e separated from the crowns with a straight cut across the root instead of the usual cone-shaped cut. All treatments differed significantly for yield of crown. Crown material each year was about 1.5 tons per acre (35%) more at the high N levels than at the low N levels. The overall crown/root ratios (0.29 in 1967 and 0.21 in 1968) show that a sizable portion of the total growth can be attributed to crowns. The difference between the two ratios (0.08) suggests that environ­ mental effects condition the development of root and crown in respect to each other. Another indication of environmental effects is that the crown/root ratio was higher in 1967, when the overall stand of beets was denser (120 per 100 feet) rather than in 1968, when stands were less dense (100 per 100 feet). Results of the spacing treatment in 1968 indicate that the ratio should be higher when beets are spaced farther apart. In addition to environmental effects, the crownlroot ratio varied significantly with all treatments except harvest dates. The greatest divergence in ratios for each year was between the two N levels (0 .09 in 1967 and 0.06 in 1968) and reflects, primarily, the large increase in crown yield at high N with little increase in root yield. Fort and Stout (5) and Loomis and Ulrich (9) also reported large increases in crown yield at high N levels. Growth rates of the root and crown are apparently proportional during the harvest season because the crownlroot ratio did not change significantly between mid-September and mid-Novem­ ber in 1967. < 0 r­ .-..J Table I.-Effect of nitrogen, plant spacing, cultivar, and harvest date on yield of sugarbeet root and crown. Z 1967 Yield Crown/Root 1968 Yield Crown/Root 0 Treatment Root Crown Total Ratio Treatment Root Crown Total Ratio .... -- - --- Tons/Acre - - - --- -- -- - - Tons/Acre - - - --- 0 n N Applied N Applied .., 0.18 0 241b/A 17.9 4.4 22.3 0.25 30lblA 17.9 3.3 21.2 to 150lb/A 17.5 5.9 23.4 0.34 150lb/A 18.9 4.6' 23.5 0.24 '":>:J ns ** •• ns • * * • Spacing <D -..J 9.8 in. 18.4 3.8 22.2 0.20 (>:) 15.4 18.4 4.1 22.5 0.22 ns ns ** Cultivar Cultivar 1 17.5 5.2 22.7 0.30 3 19.0 4.3 233 0.23 2 17.0 4.3 21.3 0.25 4 17.8 3.6 21.4 0.20 3 18.6 5.9 24.5 0.32 .* ** ** *. ** ** ** Harvest Harvest Sept. 14 15. 1 4.3 19.4 0.29 Sept. 23 17.0 3.7 20.7 0.22 Oct. 5 17.7 5.2 22.9 0.29 Oct. 21 19.8 4.2 24.0 0.21 Oct. 24 IS.8 5.4 24.2 0.29 .* ns Nov. 7 19.2 5.7 24.9 0.30 ** *. ns Test Avg. 17.7 5. 1 22.8 0.29 Test Avg. 18.4 3.9 22.3 0.21 *, •• F test significant at the 5 and I percent levels of probability, respectively. ns F t!'st not significant. (>:) (>:) <.n 336 JOCRNAL OF THE A.