麦秸预处理方式对黄绵土结构及低吸力段持水性的影响

通过土柱模拟培养试验,对比研究秸秆经过粉碎、氨化预处理及与无机土壤改良剂(硫酸钙)混合配施对黄绵土结构及低吸力段持水特性的影响。结果表明,秸秆经粉碎、氨化预处理及与土壤改良剂配施后能显著提高土壤结构稳定性,降低土壤结构分形维数。其中粉碎氨化秸秆对提高土壤稳定性具有一定的迟效性。秸秆经过不同预处理后施入土壤使土壤孔隙连通性降低,并随着秸秆的分解得到改善。其中长秸秆对土壤孔隙连通性改善作用较粉碎秸秆差。试验表明,土壤团聚体分形维数与土壤结构评价指标均呈极显著负相关关系(P<0.01),土壤团聚体分形维数FD与低吸力段土壤孔隙分形维数Dp之间呈极显著直线相关关系,相关系数为-0.80。FD与Dp两者结合分析可定量描述不同预处理秸秆对土壤结构、低吸力段持水特性的动态影响过程。

Effect of Pretreated Wheat Straw on Soil Aggregate and Water-holding Capacity within Low Suctions in Loess Soil

A contrast study on effect of powdered,aminated straw with or without inorganic soil conditioner(calcium sulfate)on soil structure and water-holding capacity in low suction section was made through soil column incubation test.The results showed that the pretreated straw significantly improved soil structure stability,decreased soil structure fractal dimension.Therein the soil with comminuted and aminated straw had a slow acting to improve soil stability.Different pretreatment of straw mixed with soil could make soil porosity connectivity poor in the early stages,and then better with the straw decomposition later.Therein the soil with long straw always kept worse soil porosity than soils with the powdered straw.Furthermore there was a significantly linear correlation between soil aggregate fractal dimension and soil porosity fractal dimension in low suction section.That quantitively explained the effect of the pretreated straw on soil structure and water-holding capacity in low suction section of soil.