Biomass production and nutrient accumulation by cover crops cultivated in the dry season

In the south-central region of the State of Sao Paulo, data on the adaptability of cover crops grown in the dry season are insuficient. The objective of this study was to investigate the biomass production and extraction of macronutrients in cover crops during the dry season, in a Oxysoil (LatossoloVermelho), in the city of Araras-SP. The design was in randomized blocks, with five treatments, corresponding to species in six blocks. In the maize off-season 2015/2016, were cultivated: crotalaria spectabilis (Crotalaria spectabilis Roth.), pigeon pea (Cajanus cajan L.), pig bean (Canavalia ensiformes L.), velvet bean (Stilozobium aterrimum Piper et Tray) and millet (Pennisetum glaucum L.). Millet was the species that produced the highest dry matter average (above 8 tons ha(-1)) and the one that most extracted macronutrients (185;10;106;42;18 and 8 Kg ha(-1) of N, P, K, Ca, Mg and S, respectively), showing a C/N ratio of less than 25, suggesting that its residues would undergo rapid decomposition and mineralization. The clustering analysis indicated that the pigeon pea had similar performance to millet. Crotalaria-spectabilis presented the lowest dried biomass extracted a smaller amount of macronutrients. In this study, millet and pigeon pea were the species that contributed the most to cover the soil and to recycle nutrients in the dry season.