Assessing soil health in a thermic region of the southern great plains, using the soil management assessment framework (SMAF)

Abstract

The soil management assessment framework (SMAF) has been widely used as a tool to quantify soil health. However, SMAF was developed using data from only a few climate conditions in the United States and regional verification is often suggested. We evaluated SMAF's short-term performance in a thermic/hyperthermic region, aiming to 1) evaluate the sensitivity of SMAF scores to changes in individual soil properties and 2) quantify soil health changes using SMAF. Treatments include two levels of summer crop and two levels of tillage in an annually planted wheat system. SMAF soil health metrics were measured for Burleson clay soil (BC site) and Parrita sandy clay loam soil (PSCL site) for 0–5 cm soil depth. At the BC site, βgluc and SOC SMAF scores displayed no statistical differences when compared to their respective soil properties. βgluc measurement also helped to highlight the treatment difference observed for wheat yield. This suggests that scoring curves of βgluc used in SMAF may need to be modified, especially for clayey soils. The results also show that SMAF scores were not correlated with wheat yield at both sites, suggesting that multiple year data may be needed to understand this relationship. Overall, in a thermic region, SMAF was found to be helpful to understand short-term soil health status. However, due to clay correction in SMAF algorithm, SMAF scores can show lower sensitivity in the clayey soils of these thermic regions.