Yield and quality of three corn hybrids as affected by broiler litter fertilization and crop maturity

Specific hybrids, fertilization and maturity impact yields and nutrient quality of corn silage. To address these effects, three corn hybrids (Zea mays L.) (Pioneer 3136, 3140, 3154) with five N fertilization (F) treatments were planted for 2 years and harvested at approximately 1/3, 2/3 or 100% milk line in a split-split plot design. Main treatments were No-F, 4.5, 9.0, 13.5 (Year 1) or 18.0 (Year 2) Mg ha(-1) of broiler litter (BrL) or 202 kg ha(-1) of NH4NO3. At harvest, milk lines and whole plant, stover and grain yields were determined. Whole plant and stover portions were chopped and subsampled for subsequent nutrient component and in vitro dry matter disappearance (IVDMD). Milk line advanced rapidly, especially during Year I that was a dry year. Whole plant yields were greatest for the 13.5/18.0 BrL treatments with no difference between 9.0 BrL and NH4NO3 treatments. Nutrient content varied with fertilizer treatment and year; during Year 1, NH4NO3 treatments had greater CP and lower ADF values, but the 13.5/18.0 BrL had the greatest CP content in Year 2, a wetter year. Whole plant lVDMD values were greater for NH4NO3 than the 13.5/18.0 BrL treatments during both years, but this occurred only during Year I for stover. Corn hybrid did not consistently affect yield, but during both years stover ADF was lower and IVDMD was higher for Hybrid 3136. These advantages existed in the whole plant only during Year 1. Increased maturity enhanced grain and whole plant yield, but effects on nutrient quality were variable. Appropriate application rates of BrL provide comparable yields to commercial fertilizer without an adverse effect on nutrient composition, although digestibility may be reduced. (C) 2001 Elsevier Science B.V. All rights reserved.