Culturas antecessoras, doses e fontes de nitrogênio nos componentes de produção do milho

Abstract

Antecedent crops, doses and sources of nitrogen on yield compounds of corn. Some plants for mulching have the capacity to increase the availability of nutrients in the soil – nitrogen in particular – for crop succession, thus producing positive effects on the interaction between mineral fertilizer and green manure. As a result, there is a greater possibility to obtain higher incomes than by using each one separately. The objective of this study was to evaluate the effect of antecedent crops, doses and sources of nitrogen on yield compounds and foliar nitrogen content of corn by means of no-tillage system. The experimental design was in randomized blocks with treatments arranged in sub-subdivided plots. These were constituted by crops preceding corn: black oat, wheat, pasture turnip, hairy vetch and one rest treatment during winter. Subplots were established by four doses of nitrogen (0; 50; 100 and 200 kg ha-1 of N), which were applied as cover. Sub-subplots were represented by two sources of nitrogen (ammonia sulfate and urea). Results showed that antecedent crops had some influence upon yield, mass of 1000 grains and foliar nitrogen content of corn. The highest yield of corn was obtained after the winter rest, the pasture turnip and also in the absence of nitrogen fertilization as cover. The maximum yield of corn was obtained when sowing was done after wheat and black oat, in nitrogen doses of 140 and 137 kg ha-1, respectively. The nitrogen sources utilized had some influence only upon the index of harvest, the number of grains per ear and the foliar nitrogen content.