Synergetic Response of Soil Aggregates and Binding Agents in the Process of Vegetation Restoration Succession

Taking Maowangou Basin in Shaanxi as the research area. Field survey and laboratory experiment were conducted to study the coordinated variation between soil aggregate stability and soil aggregate binding agents (soil organic carbon (SOC), glomalin-related soil protein (GRSP)) during vegetation succession of abandoned cropland in Loess hilly area. The results showed that vegetation succession of abandoned cropland increased >5 mm wet-sieved aggregate fractions, decreased 0.25-2 mm wet sieved aggregate fractions, and thus significantly increased aggregate mean weight diameter (MWD). Soil aggregate-associated SOC, easily extractable GRSP (EE-GRSP), and total GRSP (T-GRSP) all showed an increasing trend with the abandoned duration. Correlation analysis showed that different aggregate binding agents were obviously correlated with each other. MWD were significantly positively correlated with SOC and T-GRSP in >5 mm and < 5 mm wet sieved aggregate fractions, respectively. During the succession of vegetation in the returning farmland in loess hilly region, the increase of SOC and GRSP content synergistically improved the stability of soil aggregates.