Efeito Residual do Nitrogênio Aplicado no Inverno para Cultura do Milho em um Sistema de Integração Lavoura Pecuária

Abstract

Maize (Zea mays L.) in the summer along with grazing oats (Avena spp.) and ryegrass (Lolium multiflorum L.) in winter, fertilized with nitrogen and as integrated crop livestock, appear as options for improvement of soil use and manipulation in southern Brazil, since nitrogen fertilization may show increases in corn yields. The objective of this study was to evaluate the nitrogen residual effect applied in grassland on the maize grown in integrated crop livestock system. An experiment was conducted in the years 2011 and 2012 in Guarapuava-PR, introducing rotation of oat/rye - corn. The design was a randomized block with split plots and three replications. The effect of nitrogen fertilization (0, 75, 150 and 225 kg N ha?¹) in the pasture (plots) and its residual effect on maize production was analyzed. The residual effect of the nitrogen (N) applied to the pasture was observed in the corn which was grown in areas where there was a combination of factors: (a) N dosage in pastures and culture, and (b) presence or absence of grazing animals (subplots). In the maize (subsubplots), doses of 0, 75, 150, 225 and 300 kg ha?¹ N were used. It was found that N application on oat and ryegrass had influence on grain yield. The increased production showed the residual effect of this element, as well as the effect of the N applied directly in the culture. In addition to generating more income to the farm with livestock in winter, the grain yield of maize grown in succession was optimized by the grazing. This demystifies that the animal`s entry into the system negatively affects the successive culture. The use of N in oat and ryegrass helps to increase forage production and grain yield of the maize in succession. Many efforts have been undertaken in order to develop or adapt technologies and systems that have a pasture based animal feed, aiming, besides the reduction of production costs in the summer, at improvements in the soil use and management.