The four-quadrant model integrating soil β-glucosidase and arylsulfatase enzyme activity with organic carbon has been recently proposed as a framework to assess agricultural soil health status. Nevertheless, soil enzyme activity responses to contrasting family farming practices remain poorly understood. We evaluated β-glucosidase and arylsulfatase enzyme activity in response to conventional and agroecological family farming practices and their relationship with biological and soil fertility attributes. Four Brazilian family-based farms including horticultural and crop systems with 3–15 years of existence were studied. Soil samples were collected from the 0.00–0.10 m layer for analysis of soil β-glucosidase and arylsulfatase enzyme activities, microbial biomass carbon, basal respiration, mites and springtails abundance, pH, exchangeable calcium and magnesium, available potassium and phosphorus, and soil organic matter content. Enzyme activity, mite abundance and soil organic matter content tended to be higher in forest soil (reference). The four-quadrant model differentiated agroecological from conventional systems, with agroecological systems, particularly those combining organic inputs and soil cover, showing patterns consistent with improvement in soil health. Principal component analysis revealed similar relationships among soil attributes. These patterns may be associated with management practices such as organic fertilization, cover cropping, reduced mechanical soil disturbance, and crop rotation, which together enhance organic matter levels and stimulate microbial activity. However, longer-term or more intensive management may be required to reach the highest soil health category. The results indicate that the four-quadrant model may be a useful framework for interpreting changes in soil health under family farming systems. Soil organic matter, basal respiration, and enzymatic activity were the attributes most closely associated with soil biological functioning and may serve to diagnose and monitor soil health in family-based farming systems.
Figueiredo et al. (Thu,) studied this question.