Análise econômica da adubação nitrogenada no milho sob plantio direto em sucessão a plantas de cobertura em Latossolo Vermelho - DOI: 10.4025/actasciagron.v29i4.395

摘要

Nitrogen is the most absorbed nutrient and also the most expensive in corn crop production. This study was conducted at the Experimental Farm of Unesp/Feis, located in Selvíria, state of Mato Grosso do Sul, Brazil. One objective was to evaluate, in economic terms, the best rate and time of N application, as urea, in corn crop grown under no-tillage in succession to sunnhemp, millet and fallow ground. The study also aimed to quantify the contribution of N from green manure equivalent to N from urea fertilizer. The experiment was designed in randomized complete blocks, with 24 treatments and four replications in an incomplete factorial, 3 x 3 x 2 + 6, three N rates: 80, 130 and 180 kg N ha-1; three preceding cover crops: sunnhemp, millet and fallow ground; two N application time: stage four leaves or eight leaves; and six additional treatments (three without N application and three that received 30 kg N ha-1 at seeding). The corn crop in succession to sunnhemp and the application of N in the four leaves stage in succession to millet and fallow ground soil promoted larger physical and economical grains yield.