Biochemical indicators drive soil quality in integrated crop–livestock–forestry systems

Abstract

Integrated crop, livestock, and forestry systems (iCLF) have been widely heralded as a sustainable farming method in comparison to conventional pastures. However, intensive soil use and management modify ecosystem function, particularly biogeochemical cycling. The aim of this study was to determine whether there are changes in soil chemistry or biochemistry after the conversion of pasture into iCLF in the Brazilian Cerrado. Additionally, we compared three iCLF areas initiated 3, 5, and 8 years before this study to test the effect of time since conversion to iCLF (age) on soil chemistry and biochemistry and on microbial carbon (C). Conventional pasture and native Cerrado soils were used as controls. Microbial C and biochemical activity were dependent on the plant cover and age of the iCLF, but soil physicochemical properties were sensitive only to the agroecosystem type. Enzyme activity and microbial C were higher in native Cerrado soils, followed by iCLF and pasture soils, respectively. There was an inverse relationship between iCLF age and microbial C and β-Glucosidase and phenol oxidase activities. The results suggest that the response of the microbial community depends on the soil composition and the iCLF age. Nutrient cycling in iCLF increases with age of the system and varies by management subtype within the iCLF (i.e., forestry or grazing areas). The implementation of iCLF changes soil conditions, which generates a positive response in the microbial community. The adoption of iCLF increases microbial activity and enhances soil quality over short–medium timescales (5 years).