Apparent Energy as an Index to Evaluate the Role of Litter Inputs in Enhancing Soil Aggregate Stability for Sustainable Land Management

Soil aggregate stability (SAS) is a key indicator of soil quality, influenced by organic amendments and physicochemical properties. In this study, we developed an innovative approach that integrates soil disruption characteristics with sieving indices to evaluate SAS. A long-term incubation experiment conducted in Ziwuling Mountain investigated the effects of decomposing plant residues on SAS in soils with high soil organic carbon (SOC). Apparent energy (E_A) was compared with mean weight diameter (MWD), geometric mean diameter (GMD), and the erodibility index (K-value) across seven treatments, 1%–3% W/W leaf and branch amendments and a control (CK). SOC, C/N ratio, and pH were more strongly correlated with E_A (p < 0.05) than with MWD, GMD, and K-value. E_A values ranged 0.039–0.280 J g⁻¹ mm⁻¹, while MWD varied from 0.50 mm (CK) to 1.79 mm (high-carbon branch amendment i.e., HCB). Despite similar MWD values, HCB formed more stable aggregates than high carbon leaves amendment, highlighting the long-term benefits of branch amendments. E_A proved a superior stability indicator, providing valuable insights for soil conservation and management.