Manejo de pastagem de inverno sob sistema de integração lavoura-pecuária

Abstract

The search for sustainable production systems that can meet the high demand for food globally is one of agriculture focuses on the current scenario. One example system is the Crop-Livestock Integration (ILP), which brings together the agricultural and livestock production in the same area of cultivation. In southern Brazil mainly highlights the ILP of use with animals for grazing in winter and further cultivation of field crops. It emphasizes the use of ryegrass as winter forage, which besides providing large supply of straw on the ground, also has excellent production characteristics, quality and plasticity. Although their use is large in the region, there is no consensus on what should be the interval between the desiccation of this pasture and sowing of the summer crop and its consequences on successors plantations. Thus, the aim of this study was to evaluate the influence of different intervals between desiccation of ryegrass and corn seeding in areas with and without the presence of grazing and nitrogen fertilization on maize yield components. The experiment was conducted on a farm in the municipality of Renascença - PR in 2013 and 2014. It was made up of two experiments with and without grazing, through the design of randomized blocks, with split plots and four replications. In this case the plots consisted of three intervals between sowing desiccation (0, 15 and 30 days) and the subplots were formed by two levels of nitrogen fertilization in corn 0 and 150 kg N ha-1. For grazing were used crossbred calves of Holstein and Jersey breed through continuous grazing with variable stocking rate in order to keep the canopy with about 20 cm. For dissections used the desiccant with active ingredient Glyphosate at a dose of 2.880 g active ingredient ha-1. Seeds were sown in total area with density 65-70 thousand plants ha-1 with use of hybrid AS 1555 VT PRO Agroeste. The variable amount of straw at the time of sowing, thousand grain weight and grain yield of maize were analyzed. Held joint analysis of the experiments for the variables, as well as notes the homogeneity of the square residual medium proceeded to analysis of variance by F test and when significant subjected to analysis of variance and comparison of means by Tukey test at 5% error probability using the SAS statistical software. The experiment without the presence of grazing has a higher amount of straw on the soil in all the IDS, especially in the IDS 0. There was no effect of IDS on the amount of straw in grazed experiment. The presence of grazing positively influenced the corn yield. There was no effect of IDS on the mass productivity thousand grains of corn.