Productivity and Chemical Quality of Corn Submitted to Different Nitrogen Sources.

Brazil has more than 13.5 million ha planted with corn, and 75-80% in zero tillage and nitrogen (N) is the nutrient that most limits the yield. The objective of this study was to evaluate the effects of nitrogen fertilizer on corn yield in no-tillage. The experiment was conducted at USP-São Paulo University in Pirassununga-SP/Brazil in Oxisol, loam, clay, and the randomized complete block design with ten treatments and four replicates with standard dose of 100 kg ha^-1 N. The treatments were: T1) Control + Gypsum, T2) control absolute, T3) Urea, T4 - urea + Gypsum, T5) N + ammonium sulfate, T6) Ammonium nitrate, T7) Ammonium nitrate + Gypsum, T8) Nitrate ammonium sulfate + ammonium, T9) ammonium sulfate and T10) FASN (fusion Ammonium sulfate nitrate) - which is a fusion of ammonium sulfate and ammonium nitrate in the form of salts. The experimental plot had six rows of 0.80 m with 10 m length. It was evaluated the production of grain moisture to 13% chemical quality and grain crude protein - crude protein, acid detergent fiber - ADF and neutral detergent fiber - NDF, according to AOAC (1970). The productivity (ton/grãos/ha^-1) responded significantly (p <0.05) for N sources, with better performance for treatments T9 (7128 kg/ha^-1), T5 (7089 kg/ha^-1), T10 (7047 kg/ha^-1), T4 (6981 kg/ha^-1) and T6 (6931 kg/ha^-1). For the apparent recovery of N (kg plant N / kg N applied), there was no distinction between the fertilizers tested, as well as the chemical quality of the grains with respect to CP, ADF and NDF. Nitrogen fertilizers, particularly ammonia and nitric in the sources, resulted in favorable responses in the corn production, but did not modify the chemical quality (CP, NDF and ADF).