ADVANCING NITROGEN FERTILIZATION OF CORN USING Brachiaria ruziziensis AS COVER CROP

Abstract

ABSTRACT Advancing nitrogen (N) application in cropping systems, using cover crops, is an alternative to improve the efficiency of use of this nutrient and to optimize the operational issue. The aim of this study was to evaluate the efficiency of advancing N fertilization for corn crop, with Brachiaria ruziziensis as cover crop. The experiment was conducted at the experimental field of the Federal University of Jataí / Regional Unit of Jataí, GO, Brazil, with history of soybean-corn/sorghum succession in the last 20 years and a high organic matter content in the soil, which reaches 39.5 g kg-1. A randomized complete block design was used in a 5x2 + 1 factorial scheme with 4 replicates, corresponding to five N doses: 0; 50; 100; 150 and 200 kg ha-1 and two times of application in B. ruziziensis: Time 1 - N application 90 days before planting of corn, and Time 2 - N application 60 days before planting, plus an additional treatment with conventional N fertilization, 150 kg ha-1 of N, not advanced, applied to the corn crop, split into planting fertilization and top -dressing fertilization. Except for the N dose of 200 kg ha-1 applied 90 days before corn sowing, advancing N fertilization for this crop using B. ruziziensis as cover plant proved to be as efficient as conventional fertilization for the soil and climate conditions under which the study was carried out, that is, soil with high content of organic matter, built fertility and absence of water restriction.