Consórcio de milho com leguminosas e seus efeitos no carbono da biomassa microbiana em área de pastagem degradada

Abstract

Pasture degradation in Brazil compromises the biological quality of soils and reduces agricultural potential yield, especially in areas managed under intensive use and with low input of organic residues. The cultivation of cover legumes intercropped with main crops has emerged as a promising strategy to restore soil health and increase soil microbial biomass carbon (MBC). This study aimed to evaluate the efficiency of maize intercropped with different cover legumes in increasing MBC levels in a degraded pasture area. The experiment was conducted in a randomized block design with four replications, consisting of the following treatments: sole maize; maize intercropped with Crotalaria spectabilis; maize intercropped with Canavalia ensiformis (jack bean); and maize intercropped with Mucuna pruriens (mucuna). Soil samples were collected at a depth of 0–20 cm, and MBC was determined using the fumigation–extraction method. The results showed that the intercrops with Crotalaria and jack bean promoted expressive increases in MBC levels — 202% and 134%, respectively — compared with sole maize, while mucuna showed no significant statistical difference relative to the control. It can be concluded that legumes capable of producing high biomass and exhibiting a low C/N ratio are more efficient at stimulating soil microbial activity, indicating that the intercropping of maize with Crotalaria and jack bean is an effective strategy for restoring degraded soils and promoting more sustainable production systems.