Environmental and management drivers of soil health indicators on Michigan field crop farms

Abstract

Maintaining soil health is critical for sustainable field crop production. This on-farm study used participatory monitoring and employed a Bayesian linear regression model to investigate the impact of various drivers (i.e., climate, soil edaphic properties, management practices, cropping diversity, and tillage intensity) on soil health indicators. Over two years, we sampled 242 focal points in soybean fields on thirty-five farms across three regions in Michigan differing in climate, edaphic properties and management practices. Soils ranged from loam to sandy loam. Soil health indicators assessed included soil organic carbon (SOC), total soil nitrogen (TSN), permanganate oxidizable carbon (POXC), C mineralization (Cmin), potentially mineralizable nitrogen (PMN), phosphorus, calcium, soil surface and subsurface resistance, and wet aggregate stability (WAS). We observed location effects, with each of the three regions differing in their climate, soil edaphic properties, and management practices. We found that aridity and clay content are primary drivers of most soil health indicators. Specifically, crop diversity, irrespective of composition, was positively associated with Cmin and WAS. Tillage intensity was positively associated with PMN but negatively influenced POXC. Overall, we conclude that although climate and soil edaphic properties are the dominant drivers of soil health, management practices also play a critical role, especially when considering soil biological indicators.