Soil health quantification via SMAF and CASH across diverse land uses

Abstract

Soil health quantification helps to visualize soil health conditions across different agroecosystem land use and management practices. However, using different soil health platforms for soil health quantification may lead to varying outcomes. This study quantified soil health via two frequently used soil health frameworks, namely the Soil Management Assessment Framework (SMAF) and the Comprehensive Assessment of Soil Health (CASH), across eleven sites pertaining to different land use management strategies, including a deciduous (DF) and an evergreen forest (EF), managed pastures including a livestock integrated beef pasture (BP) and a pasture for hay harvesting (DP), and seven crop lands with multiple management practices. Results suggested that managed pasture sites were associated with the best overall soil health scores within both frameworks (BP 0.92 and 81, DP 0.90 and 79, for SMAF and CASH, respectively). Among all crop fields, a certified organic managed site showed the greatest soil health (0.88 and 75 for SMAF and CASH, respectively), primarily due to soil organic carbon (SOC) accumulation. Most soil health indicators included in SMAF and CASH were sensitive to present land use and management practice differences. However, the result for active carbon (from CASH) was not sensitive to land use, and the findings indicated that β-glucosidase activity (from SMAF) was merely correlated to soil pH. The overall soil health scores generated from these two frameworks were significantly correlated (r = 0.58), and the outcome of both frameworks was driven largely by soil biological indicators (r = 0.87 for both SMAF and CASH, respectively). The overall soil health scores suggested that CASH was more sensitive to land use and management practices compared to SMAF based on a wider spread in overall soil health scores across land uses and management practices in the cultivated fields. The use of forested sites as a potential soil health benchmark for cropped lands was not feasible primarily due to their low soil pH (DF = 5.41 and EF = 4.22) that likely supported different soil biogeochemical process as compared to managed agroecosystems. In contrast, results from this study suggest that managed pastures (BP and DP) are a more promising benchmark for assessing soil health in croplands within this region of the U.S.