Inga edulis Mart. intercropped with pasture improves soil quality without compromising forage yields

Abstract

This study evaluated the effect of Inga edulis trees on soil quality attributes and forage yield and moisture in a pasture field in the county of Carrancas, Minas Gerais, Brazil. Soil samples were collected under the canopy and beyond the canopy projection of five I. edulis trees, at four distances from the tree trunks to beyond the canopy projection, along the radius line. A randomized block design was used, in which five trees represented five blocks and the four distances from the trees corresponded to the treatments. The forage yield and moisture, soil moisture and chemical attributes, density and diversity of arbuscular mycorrhizal fungi (AMF) spores and the presence of nodule-forming nitrogen-fixing bacteria in legumes were evaluated. The statistical analysis was performed using ANOVA and the Scott-Knott test (p = 0.05). No statistical differences between forage yield and moisture were found in the soil under or beyond the canopy projection. The soil quality was elevated, indicated by the improved soil pH, base saturation, sum of bases and effective cation exchange capacity in the samples collected closer to I. edulis. No changes in the density and diversity of AMF spores or in the nodulation and development of inoculated seedlings were observed in soil collected at different distances from the trees. Consequently, I. edulis trees can be intercropped with pasture to increase the soil quality without affecting forage yields.