不同胶结物质对黄绵土团聚体形成的影响

Effects of Cementing Materials on the Formation of Loessial Soil Aggregates

通过室内培养试验,采用PAM、腐殖酸、壳聚糖、硫酸铝4种土壤结构胶结剂对促进黄绵土<0.25mm团聚体形成大团聚体的过程和效果开展研究。结果表明:(1)从新形成土壤团聚体的粒径分布来看,4种胶结剂均有利于<0.25mm粒径的团聚体形成更大的团聚体,尤其是对于增加>5mm的土壤团聚体含量效果明显;(2)4种胶结剂施入<0.25mm黄绵土团聚体,均可有效地增加黄绵土团聚体的平均重量直径和几何平均直径,提高了团聚体稳定性,且随胶结剂施用浓度的增加呈升高趋势;(3)不同胶结剂对促进黄绵土团聚体形成的能力表现为腐殖酸≈PAM>壳聚糖>硫酸铝。研究结果可为合理利用外源胶结剂改善土壤结构提供一定的科学依据。

In this study, PAM, humic acid, chitosan and aluminum sulfate were used as soil cementing materials to research the processes and effects on the formation of large aggregates from d0. 25 mm aggregates in the loessial soil. The results showed that. （1） Based on the analyses of soil particle size distribution, soil cementing materials used in this study were all beneficial for the formation of 〉2 mm aggregates, especially for 〉5 mm aggregates. （2） All of these four cementing materials could effectively increase the mean weight diameter and mean geometric diameter of the loessial soil, and enhance the stability of aggregates, which increased with the increasing application rate of the cementing materials. （3） Different soil cementing materials had different ability to improve soil structure, and showed the order of PAMhumic acid〉chitosan〉aluminum sulfate. The findings obtained from this work will provide theoretical supports for applying soil cementing materials to improve soil structure scientifically.