基于Le Bissonnais法的东北黑土区土壤团聚体稳定性研究

Study on soil aggregate stability of farmland based on Le Bissonnais method in the black soil region,Northeast China

土壤团聚体的组成和稳定性是衡量土壤结构和质量的重要指标,应用Le Bissonnais法对我国东北农田黑土团聚体的数量和稳定性进行了分析.团聚体粒级分布受快速湿润(FW)、慢速湿润(SW)和预湿后扰动(WS)处理的影响,FW使大团聚体多破碎为微团聚体;团聚体的平均重量直径(MWD)表现为FW<SW<WS,表明黑土团聚体破碎的主要机制是消散和黏粒膨胀,而低强度的机械扰动破坏最小.黑土团聚体稳定性指标(MWDFW、MWDSW)与有机质含量呈显著正相关,与黏粒含量呈显著负相关,表明有机质对黑土团聚体的形成和稳定有促进作用,黏粒含量影响团聚体的稳定性.

The composition and stability of aggregate are used as indicators for soil structure and soil quality. The aggregate size distribution and aggregate stability in black soil were measured by Le Bissonnais method. The aggregate size distribution of aggregates after fast wetting （FW）, slow wetting （SW） and wet stirring （WS） treatments was significantly affected by treatment method. The FW treatment had the largest aggregate disruption while WS treatment the lowest, the order of MWD was WS〉SW〉FW. It suggested that aggregate breakdown in black soil was mainly caused by the compression of air entrapped inside aggregates and clay swelling during wetting while small mechanical stirring the least. There was a significant relation between MWDFW, MWDsw and organic matter. The aggregate stability indices were significantly negatively related to clay content, which suggested that the organic matter is the main cementing and stabilization agent of aggregate, and clay content affects the aggregate stability.