秸秆不同还田方式对土壤结构及土壤蒸发特性的影响

Study on the Influence of Different Straw-returning Manners on Soil Structure and Characters of Soil Water Evaporation

利用团聚体分形维数、孔隙分形维数等指标,对比分析了秸秆在经过粉碎、氨化及与无机土壤改良剂混合3种措施处理后加入土壤对土壤团聚结构、土壤容重、孔隙度及低吸力段土壤水分蒸发特性的影响,结果表明:粉碎并氨化处理过的秸秆施入土壤后,能显著改善土壤团聚结构,减小土壤容重,增加土壤孔隙度;秸秆加入土壤中会导致处理低吸力段土壤孔隙分形维数变小,孔隙分布均匀性、连通性变差,导致土壤蒸发速率过快,而无机土壤改良剂(氢氧化铁)能有效改善土壤孔隙分布,抑制土壤蒸发,当其与秸秆混合施用时,对雨水保蓄利用效果更好。

Based on the analysis of fractal dimension of soil aggregates and soil pore in low suction range,the influence of the wheat straw,comminuted,aminated or mingled with inorganic soil amendment,on the soil structure,soil bulk density,soil porosity and characters of soil water evaporation,after mixed with the soil was studied. Compared with control,the straw comminuted and aminated added into soil can observably improve the soil aggregate structure,reduce the soil density and increase the soil porosity;wheat straw added into soil can make fractal dimension of soil pore smaller than the control,and can make the uniformity and connectivity of soil pore worse,then the evaporation rate was increased. Inorganic soil amendment can amend the soil pore distribution and restrain the soil water evaporation. So it can benefit more for the usage of rainwater resource if the comminuted and aminated straw was used with inorganic soil amendment.