Sistemas de produção de milho sob adubação nitrogenada e plantas de cobertura do solo

Abstract

The no-tillage system is the predominant model in the agricultural scenario of southern Brazil. Thus, the use of cover crops is significant due to the addition of biomass to protect the soil surface, and contribute to the cycling and/or fixing of nutrients, and in particular nitrogen (N) with liberation for the subsequent culture. Among the cool season species, it was found predominant use of oat to obtain straw to system. Though large quantities input of residue is not the preferred species to precede the corn, cereal with relevant importance in the Paraná Southwest region. It was aimed to evaluate the productivity capacity of corn in no-tillage, in the absence or presence of nitrogen fertilization, on waste of winter cover crops on soil and climatic conditions of the Paraná Southwest region. The installation of no-tillage was held in 2010 in the experimental area belonging to UTFPR, Campus Dois Vizinhos, on a Red Latosol. For the present study, we used data relating to three agricultural years (2012/2013, 2013/2014 and 2014/2015). The experimental design was randomized block design with split plots with three replications. The main plots consisted of systems composed by cover crops (black oat, ryegrass, rye, turnip, vetch, white lupine, aot+vetch consortium and oat+vetch+turnip), preceding corn. In the subplots were used two doses of nitrogen fertilization (0 and 180 kg ha N) coverage in maize.The biggest coverage rates occurred in the consortium with 95% at 62 days after sowing. The residual effect of 180 kg ha cool season plants following year. The residual effect of 180 kg ha systems, reduced in 21% the C/N ratio of poaceae. The common vetch accumulated 32 kg N per ton of MS added. The oat and rye keeps more than 50% waste to the land cover, after 120 days, while the ryegrass and vetch provide low soil protection. Consortium oat+vetch+turnip, vetch and white lupine, released the largest amounts of N, between 52 and 59 kg ha brassica and consortia positively influencing the diameter and length of cobs, number of kernels per row and, total number of grains per ear of corn, in the absence of mineral N. The weight of a thousand grains was increased by 12.4% by the addition of 180 kg ha increase in productivity of grain by the addition of 180 kg ha N, was 2.1 Mg ha 5.6 Mg ha 6.4 Mg ha components when cultivated on vetch. Systems containing fabaceae, brassica and consortium oat+vetch+turnip, predating the corn, in the absence of mineral N, provided similar grain yelds inrelation to the systems with the addition of 180 kg ha Keywords: Cover crops. No-tillage. Grain yield. Zea mays - 1 -1 N, increased 4.8% coverage rate in the of N in corn/cover crops -1 -1 . Fabaceae, -1 N mineral. The average N, in relation to dose 0 kg ha corn kernels on fabaceae, brassica and consortium oat+vetch+turnip, and poaceae the grains in succession. The consortium added amount between 4.0 the DM in the years of study. There was no effect of mineral N rate for corn yield components when cultivated on vetch. Systems containing fabaceae, brassica and consortium oat+vetch+turnip, predating the corn, in the absence of mineral N, provided similar grain yelds inrelation to the systems with the addition of 180 kg ha-1 N.