Adubação nitrogenada na cultura do milho no sistema plantio direto em ano com precipitação pluvial normal e com "El Niño"

In this study the split application of nitrogen and the maize crop pre-sowing nitrogen application under a no-tillage system followed by black oat, with two rainfall regimes were evaluated. Treatments were: (a) application of 150 kg ha(-1) of N in pre-sowing and 30 kg ha(-1) of N at sowing with 1997 / 98 "El-Nino" rainfall applications, (b) nitrogen application, being 30 kg ha(-1) of N at sowing, and 30 kg ha(-1) of N at 31 and 57 days after emergency (DAE), with "El-Nino" rainfall applications, (c) without N application and "El-Nino" rainfall applications and, (d) nitrogen application (b treatment), with normal rainfall applications. The experiment was conducted during 1998199 growing season, at the Federal University of Santa Maria, in a completely randomized design, with two replications. A set of eight drainage lysimeters was used, protected from natural rainfall through an arch rain shelter. Leaf area index, plant height, above ground dry matter, grain yield and percent of N in maize grain and dry matter were evaluated. Nitrogen application on both water regimes had no effect on plant leaf area index, plant height, grain yield, percent of N in grains and N translocated to grains. Above ground dry matter and the amount of N carried out to shoot were smaller for the treatments submitted to normal rainfalls, compared to the ones that received N applications and "El-Nino" rainfalls.