Leguminosas como fonte de nitrogênio para o milho em Pernambuco

Abstract

Legume use in agriculture is advantageous and lucrative since it brings yield gains with simultaneous benefits to soil and environment, being thus economically possible and ecologically acceptable. To this end, legume green manuring might be one of the most viable proposals to the new paths of sustainable agriculture in tropical environments. Legume species diversity allows ample usage as live or dead vegetation cover, configuring different agronomical practices with beneficial effects on soil such as C and N retention, which result on yield gains for subsequent crops. So, including forage or grain legumes in a cropping system might increase main crop yield and benefit the farmer. This research, thus, aims to evaluate common beans (Phaseolus vulgaris), cowpea (Vigna unguiculata), peanuts (Arachis hypogaea), Campo Grande stylo (Stylosanthes spp), calopo (Calopogonium mucunoides), black velvet (Styzolobium aterrimum) and sunn hemp (Crotalaria juncea) in subsequent corn, as well as their effects on native soil microbial biomass and activity and soil C and N contents. In short, green manure legumes, independently of the species, enhanced soil quality, with lower soil C losses and soil N gains and that dead legume cover retains more soil C than live cover being more sensitive than total C, confirming thus the need to study microbiological indicators of soil quality particularly in tropical ecosystems. Another important aspect is that green manure legume usage increases yield in the major crop, and so deserve attention as in peanuts, which also acts as an income source. Legumes typically used for green manure tend to show high biomass yield, and consequently allow higher yield for the subsequent cultures.