Effect of Biological Crust Mulching on Distribution Characteristics and Stability of Soil Aggregates in Loess Hilly Region

  Objective  The effects of soil crusts types on the soil organic carbon and the stability of soil aggregates were studied under the soil crust mulching (algal crust, moss crust, mixed soil crust and bare soil) in the rocky area of Lüliang.

  Method  The relationships between soil bulk density (SBD) , soil organic carbon (SOC) and soil static water disintegration rate (B) and the stability of soil aggregates were investigated by dry and wet sieving methods.

  Result  The results showed that there were significant differences between SBD and bare land at the depth of 0 ~ 5 cm and 5 ~ 10 cm. The SOC of Moss mixed crust and Moss crust increased significantly than that of bare soil. In different depth of soil layers, the aggregate broken rate (PAD) and fractal dimension (D) were Bare Land > Algal Crust > Moss Crust > Moss Mixed Crust, but the mean weight diameter (MWD) and geometric mean diameter (GMD) were opposite. The correlation analysis showed that the contents of soil aggregate (R_0.25) were negatively correlated with SBD, and the contents of PAD, D were positively correlated with SBD and B, and negatively correlated with SOC. MWD, GMD and SBD showed a significant negative correlation, a significant negative correlation with B, and a significant positive correlation with SOC.

  Conclusion  With the increase of soil crust succession, the ability of soil aggregate formation and the water stability of soil aggregate increase gradually in Lüliang Loess Hilly region, and the content of soil organic carbon plays a dominant role in soil water stability.