Potentials and drivers of soil quality improvement - an index based on-farm evaluation

Farm management can improve soil quality, however, these management effects on soil quality can be challenged with increasing management intensity. It is vital to understand the farm management affecting soil quality and to determine the appropriate management for a given soil system. In this study, we conducted an assessment of the impact of agricultural management practices on soil quality. This was achieved through an on-farm comparative analysis of conventional farming (arable standard), conservation farming (arable pioneer), and unmanaged reference (non-arable reference) soils across 21 sites, with three distinct soil depths (0-5 cm, 5-20 cm, and 20-35 cm). To assess the variations in soil quality, a Soil Quality Index (SQI) was formulated, integrating soil chemical, physical, and biological properties. The results indicated that the SQI was developed based on soil microbial biomass (MBC), carbon use efficiency (CUE), carbon acquiring enzymes (C enzymes), and soil aggregate stability (Aggstab). Significant variations in SQI values were identified among the three agricultural management practices when subjected to identical soil depths (p < 0.05). Our results showed that the implementation of arable pioneer management results in a 22.0% improvement in soil quality relative to standard. Moreover, our findings indicate that MBC is the primary determinant of soil quality across all depths, followed by C enzymes. Additionally, the contribution AggStab to explaining soil quality variance increases with soil depth. Our results demonstrated that compared with conventional farming, lighthouse farms can improve soil quality, and an index tool for tracking soil health progress in regenerative lighthouse farms were proposed. This underscores the necessity of developing adaptive agricultural management strategies that incorporate SQI status to achieve sustainable management of arable soil systems.