Effect of sulfur fertilization on chemical composition, ensiling characteristics and utilization of corn silage by...

Effects of S fertilization, 0 or 67 kg S/ha, as (NH4)2SO4, as a single or split application on chemical composition, ensiling characteristics and utilization of corn (Zea mays L.) silage by wether lambs was investigated. Corn forages were ensiled at hard-dent stage at 35% dry matter (DM). Sulfur fertilization increased (P less than .01) total S and SO4 but had no effect on N, Mg, Ca or fiber components in silages. Sulfur-fertilized corn silages (N:S = 42 and 43) and non-S fertilized silage (N:S = 62) were fed alone and supplemented with Na2SO4 at two rates to achieve N:S ratios of 12 (high) and 45 (low, to approximate S-fertilized silage), to 30 wether lambs (Suffolk and Dorset crosses) in metabolism and palatability trials. Both trials were randomized complete-block designs. Lambs weighed 36 and 41 kg, respectively. All silages were supplemented with 6.7 g urea/d. Digestibility of DM and cell wall components, and apparent absorption of S and N were increased (P less than .05) by S fertilization and supplementation. Nitrogen retention was increased (P less than .01) by S fertilization and supplementation. Retention was higher (P less than .001) for lambs that were fed S-fertilized silage, compared with supplementation to achieve a similar N:S ratio. It appears that S fertilization was more effective than S supplementation in improving efficiency of N utilization.