冲洪积平原土壤低吸力阶段水分特征曲线影响因素研究

Study on Influencing Factors of Water Characteristic Curve of Alluvial-diluvial Plain Soil at Low Suction Stage

为了获得冲洪积平原水成土低吸力阶段土壤水分特征曲线的影响因素,基于汾河灌区三个典型水成土剖面土壤水分特征曲线的测量,探讨了质地、结构(包括容重和大于0.025 mm水稳性团聚体含量)、有机质含量对低吸力阶段土壤水分特征曲线的影响机理。结果表明:①土壤质地、结构、有机质含量对土壤水分特征曲线均有显著的影响;②土壤内孔隙的大小、分布和连通性是决定土壤水分特征曲线差异较大的根本原因;③土壤级配对土壤内部孔隙的影响不可忽视,合理的级配能够很大程度的提高土壤的保水性能。研究结果对于土壤水分特征曲线的精细研究具有一定的意义,为科学合理灌溉提供理论支撑。

In order to obtain the influencing factors of the soil water characteristic curve of the low-suction stage of the aeolian soil in the alluvial plain,based on the measurement of soil water characteristic curves of three typical water-bearing soil profiles in Fenhe Irrigation District,this paper explored the influence mechanism of texture and structure(including bulk density and water-stable aggregate content greater than 0.025 mm)and organic matter content on soil moisture characteristic curve in low suction stage.The results show that:①soil texture,structure and organic matter content have significant effects on soil water characteristic curve;②the size,distribution and connectivity of pores in the soil are the fundamental causes for determining the difference in soil water characteristic curves;③the influence of soil level on the internal pores of the soil cannot be ignored,and reasonable gradation can greatly improve the water retention performance of the soil.The research results have certain significance for the fine study of soil water characteristic curve and provide theoretical support for scientific and rational irrigation.