Evaluation of Fodder beet (Beta vulgaris L. var.Crassa) Cultivars under Different Spacing and Nitrogen Levels

Abstract

A field experiment was conducted for two consecutive seasons (2007/08 – 2008/09), at the Demonstration Farm of the College of Agricultural Studies (Shambat), Sudan University of Science and Technology, to study the effects of nitrogen fertilization and plant spacing on growth, yield and quality of three fodder beet cultivars . The design used was a factorial Randomized Complete Block Design (RCBD) arranged in split -split plots with four replicates. Nitrogen treatments at a rate of 0, 40, 80 and 120 kg N/ha were assigned to the main plots applied eleven days from planting. Plant spacings (15, 20 and 25 cm between holes) and fodder beet cultivars (Voroshenger, Anisa and Polyproductiva) were allotted to the sub and sub-sub-plots, respectively. Two feeding trials were conducted at the milk farm of the Faculty of Veterinary Medicine and animal Production (Kuku), Sudan University of Science and Technology, in the two successive seasons (2008 and 2009), to evaluate and compare the feeding value of fodder beet compared to Abu 70. Both fodders were fed to two separate groups of cross-bred (Frisian X Kenana) milking cows and their impact on feed intake, milk yield, milk composition and economics of feeding was examined. The design used was completely randomized (CRD) with five replications. Ten dairy cows, at mid and late lactation were used and housed individually. The dietary treatments were 20kg of fresh fodder beet (tubers and leaves mixed at a ratio of 2:1) and 20Kg of fresh of Abu 70 given to the treated cows and the control ones, respectively. All cows in the two trials groups were given 7 kg of concentrate per head per day. Water and mineral licks were offered ad libitum throughout the six weeks of the trial during the two seasons. Nitrogen application increased root diameter, shoot length significantly (p<0.05) in both seasons and plant height in the second season; root fresh weight, dry weights of shoot, root, plant; green and dry fodder yields XIII significantly (p<0.05) and plant height highly significantly (p<0.01) in the first season. Nitrogen had no significant effects on number of leaves root length, shoot and plant fresh weights. Wider spacing significantly (p<0.05) increased number of leaves, root diameter, root dry weight and plant dry weight in the first season. Green and dry fodder yields were significantly (p<0.05) increased under closer spacing in the second season. Spacing had no significant effects on root length, shoot length, plant height, root fresh weight, shoot fresh weight, plant fresh weight and shoot dry weight. Cultivars exhibited highly significant (p<0.01) differences in number of leaves, root diameter, root length, plant height and shoot dry weight in both seasons. Cultivars had significant effect on shoot fresh weight in the first (p<o.o5) and second (p<0.01) seasons. Cultivars exerted a significant (p<0.05) effect on shoot length in the first season. Fresh and dry weights of root and plant, green and dry fodder yields were not significantly affected by cultivars. Application of 80 kg N/ha and sowing at 25cm apart (N2S3) increased root length highly significantly (p<0.01) and plant height significantly (p<0.05) in the first season. Shoot dry weight was significantly greater under higher nitrogen levels and wider spacing (N2S2 and N3S3) in the second season. Nitrogen and cultivars interaction resulted in significant(p<0.05) increase in leaves number and root dry weight attained by Voroshenger and Polyproductiva cultivars under 80 kg/N/ha (N2V1 and N2V3) in the first and second season, respectively. Polyproductiva sown at 25cm apart (S3V3) significantly (p<0.05) attained the greatest root dry weight in the second season. Nitrogen fertilization reduced dry matter content highly significantly (p<0.01). However, it increased crude protein and ether extract highly significantly (p<0.01) and crude fiber significantly (p<0.05) in the first season XIV and crude protein and nitrogen free extract significantly (p<0.05) in the second season. Leaves exceeded tubers in crude protein, crude fiber and ash highly significantly (p<0.01) while tubers were superior over leaves in dry matter and nitrogen free extract. Tubers without nitrogen fertilization and under 40 and 120 kg N/ha highly significantly (p<0.01) attained the greatest dry matter and nitrogen free extract. Leaves with 40 and 120 kg N/ha recorded the highest crude protein and crude fiber. Leaves under 40 and 80 kg N/ha attained the highest ether extract while those with 80 and 120 kg N/ha recorded the greatest ash contents. Nitrogen, phosphorus, sodium, magnesium, zink and iron were significantly (p<0.05) increased by nitrogen fertilization while calcium was reduced. Sulfur and chloride showed inconsistent response to nitrogen fertilization. Leaves contents of nitrogen, phosphorus, calcium, magnesium and zink were higher than tubers and the reverse was true for potassium and sodium. However, chloride, sulfur and iron of beet parts showed inconsistency variation. Nitrogen fertilization and beet parts interaction increased contents of nitrogen (N1L, N2L, and N3L) and chloride (N2L, N1Tand N3T) highly significantly in both seasons, calcium (N1L) in the second season, zink (N1L) and sulfur (N2L) in the first season. Nitrogen X beet parts interaction significantly increased phosphorus (N3T) and magnesium (N2T) in the first season and potassium and sodium (N1T), sulfur (N2T), zink (N3L) and iron (N2T) in the second season. The dry matter intake of beet was less than that of Abu 70 due to difference in dry matter percentage. Neither milk yield nor its composition (fat, lactose and solids-non fat) were significantly different between cows fed on beet and those fed on Abu 70. The nutritive value of beet forage was better than Abu70 in terms of low CF content, high amounts of NFE (carbohydrates), CP and ME. The feeding value of beet forage was by far superior to Abu70 as reflected in the lower DM intake and equal or superior yields of milk by cows fed on beet XV without any adverse effects on milk quality. Feeding of fodder beet significantly decreased daily cost of feeding by cows in the two seasons by >30% and increased profits.