Ciclagem de fósforo por plantas de cobertura e produtividade de milho segunda safra em plantio direto

Abstract

Currently, fertilization is one of the factors that most economically affects the national agricultural activity, since it represents a large share of the cost of production. To cover this problem, Latosols are naturally deficient in phosphorus, due to their interaction with the soil colloids, which causes fixation and low availability, so that the doses supplied in the fertilization have to be greater than that required by the plant. In this sense, the us e of cover crops has shown to be a promising practice in the cycling of the nutrient for subsequent crops, since its decomposition promotes the release of organic phosphorus, which is the most available source of the plants. The objective of this work was to evaluate and quantify the phytomass production, decomposition and release of phosphorus by different cover crops and yield of maize crop in second season, in Latosol (LVAd), in Sinop, MT. The design was in randomized blocks, with arrangement of plots subdivided according to sampling time and four replications. The cover plants studied were: Pennisetum glaucum, Crotalaria spectabilis, Urochloa brizantha, Eleusine coracana and Mucuna pruriens. The remaining nutrients were evaluated at 0, 15, 30, 45, 60, 90, 120, 150 and 180 days after desiccation of the cover plants. Urochloa brizantha and Pennisetum glaucum stood out in the phytomass production, accumulation and release of phosphorus. The highest yield of maize was obtained with strawberry cultivation of Urochloa brizantha. Being a species of great potential to be recommended for the cultivation with the corn in succession.