东北典型黑土区坡耕地涝渍地土壤持水性和导水性研究

中国东北典型黑土区是我国重要的商品粮生产基地,对我国粮食安全和国民经济的稳定起到举足轻重的作用。作为土壤退化的一种特殊形式,涝渍地严重影响着垦区的农业生产。在东北典型黑土区坡面涝渍地及其周围正常耕地中布设采样点,测定了土壤剖面质地分布情况及土壤水分特征曲线,以揭示东北黑土区坡面涝渍地土壤水分过大的根本原因。结果表明,涝渍地土壤剖面中细质地土壤类型所占比例为90%,质地较粘重。涝渍地土壤具有较高的进气值,水吸力较大,保持在中小孔隙中的水分只有在较大吸力范围内才能缓慢释出,这造成涝渍地土壤具有极强的持水能力,不容易失水,再加上极弱的导水能力,水分饱和但不会被释放。以上这些土壤特性导致了涝渍地土壤长期处于湿度过大的状态。本研究结果可为涝渍地治理提供依据。

Properties of Soil Water Retention and Hydraulic Conductivity in the Waterlogged Land over Slope Cropland in Typical Black Soil Region of Northeast China

The typical black soil zone in northeast China is an important commodity grain production base in China and plays crucial roles in the national food security and economic stability.As a special form of soil degradation,waterlogged lands severely affect the agricultural production in reclamation regions.The objective of this study was to analyze the soil water retention characteristics and hydraulic conductivity of waterlogged land and try to find the cause of waterlogged land.The sampling points were set in and around the waterlogged land over the slope cropland in typical black soil region of northeast China.The soil texture distribution along the soil profiles and soil water retention characteristics were measured.The results showed that the fine soil texture accounted for 90 ％ in the soil profile in waterlogged land.It resulted in a very adhesive soil texture.The waterlogged soil had higher air intake value and the larger water suction than the nonwaterlogged soil.Therefore,the water in waterlogged soil pore could be released under the much larger water suction.In addition,the waterlogged soil has the strong water holding capacity and the weak soil hydraulic conductivity,which indicated that the water in the saturated soil can not be released and that the soil keeps high soil moisture.The above soil properties are the important reasons that the waterlogged soil remains a wet condition for a long time.These results could provide the technique supports for the control for waterlogged lands.