Soil health indicators respond to management practices on commercial farms

• Assessed the effects of 4 management practices on 6 soil health indicators across 50 fields. • Manure application was consistently positively related to greater soil health. • Reduced tillage intensity was positively related to greater soil health for a subset of indicators. • Living crop cover and crop diversity were both not strongly related to soil health values. Soil health is an objective of management practices including reduced tillage intensity, manure application, crop rotation, and cover crops. However, the relative effectiveness of these practices for promoting healthier soil remains uncertain. We assessed the responses of six soil health indicators (soil organic matter, soil respiration, permanganate oxidizable C (POX-C), soil protein, mean weight diameter of water stable aggregates, and bulk density) to four management practices (manure application, reduced tillage, living cover in fall and spring, and crop diversity) across 50 commercial crop fields in Ohio and Indiana, USA. Simple linear regression, multiple linear regression and random forest analyses largely identified similar relationships between soil health and management practices. Manure application rate was consistently and positively associated with greater soil health values, although the relationship with bulk density was weak. Reduced tillage intensity was associated with greater protein and respiration, but decreased POX-C. Living cover and crop diversity each had limited relationships with the soil health indicators. Soil texture was an important factor driving variability in most soil health indicators. Reducing the management period from 5 yr to 3 yr tended to reduce the predictive ability of the models, but with limited exceptions similar relationships between management and soil health were identifiable. The depth of measurement of soil health indicators changed the interpretation of management-soil health relationships in only one instance (POX-C vs. reduced tillage intensity). Overall, manure application was the most effective practice for improving soil health, with reduced tillage intensity also effective for improving several soil health indicators.