Regenerative grazing and grassland management enhance soil extracellular enzyme activity and alter microbial nutrient acquisition

Regenerative agriculture is a global movement aimed at improving agricultural sustainability by prioritising soil health and function. A key component of soil function is soil microbial activity, which underpins pasture productivity and nutrient use efficiency through the cycling of carbon (C), nitrogen (N) and/or phosphorus (P). The microbial community is highly sensitive to management change; however, soil extracellular enzyme responses remain poorly quantified in regenerative pasture systems. We compared regenerative and conventional system effects on soil extracellular enzyme activity in a dryland grazed farmlet experiment. The regenerative system comprised a 12-species diverse pasture mix with short grazing periods and extended recovery, while the conventional system used best-practice grazing of Medicago sativa L. Both systems also included high and low soil P fertility treatments. In each system, activities of eight soil extracellular enzymes were measured in spring and autumn over two years from October 2023 to April 2025. After 3.5 years (autumn 2025), regenerative management increased several extracellular enzyme activities compared with conventional lucerne pasture: β-xylosidase (+66%; P < 0.0001), β-1,-4-N acetylglucosaminidase (+53%; P < 0.0001), β-glucosidase (+31%; P < 0.0001) and acid phosphatase (+21%; P = 0.01). In contrast, enzyme activity showed a limited response to soil P fertility. Enzymatic stoichiometric ratios indicated increased investment in P and C acquisition relative to N acquisition, suggesting persistent microbial P and C demand. These results indicate that regenerative pasture management can influence microbial activity and nutrient cycling, as well as challenge the assumption that elevated measures of soil labile P (Olsen P) alone alleviates microbial P demand in grazed grassland soils.