斥水程度对脱水土壤水分特征曲线的影响
发布时间：2018-12-27 18:32
【摘要】：为研究斥水程度对土壤水分特征曲线的影响,该文基于滴水穿透时间法,人工配置7种斥水程度的黏壤土(L0~L6)和6种斥水程度的砂土(S0~S5),用高速离心机测定其土壤水分特征曲线,应用van Genuchten-Mualem(VG)模型进行拟合,得出VG模型水力参数。结果表明:在同一吸力条件下,斥水黏壤土的含水率比斥水砂土的高;随着斥水程度增加,在相同吸力情况下,土壤含水率随斥水程度增大而减小;斥水黏壤土的残余含水率随着斥水程度增加而减小,斥水砂土S0~S3的残余含水率没有差异,S4、S5的残余含水率显著减小;斥水黏壤土和砂土进气值的对数与斥水剂添加量呈负线性相关;随着斥水程度增加,田间持水率减小,凋萎系数没有明显差异,重力水增加,有效水和易有效水减小,易利用水比例随着斥水程度增加而减小;对于斥水黏壤土,微孔隙(0.3~5μm)和小孔隙(5~30μm)含量随着斥水程度的增加明显减小,土壤空隙(≥100μm)随着斥水程度的增加急剧增加;对于斥水砂土,中等孔隙(30~75μm)的含量随斥水程度的增加明显增加。该研究成果可为斥水土壤的入渗、蒸发和数值模拟提供理论支持。
[Abstract]:In order to study the effect of water repellent degree on soil moisture characteristic curve, seven kinds of clay loam (L0~L6) with water repellent degree and six kinds of sand (S0~S5) with water repellent degree were manually configured based on drip penetration time method. The characteristic curves of soil moisture were measured by high speed centrifuge and fitted by van Genuchten-Mualem (VG) model. The hydraulic parameters of VG model were obtained. The results showed that under the same suction condition, the moisture content of water-repellent clay loam soil was higher than that of water-repellent sand soil, and with the increase of water repellent degree, the soil moisture content decreased with the increase of water repellent degree. The residual moisture content of water-repellent clay loam decreased with the increase of water repellent degree, but the residual moisture content of S0~S3 of water-repellent sandy soil was not different, while the residual moisture content of S _ 4 / S _ 5 decreased significantly. The logarithm of intake value of water repellent loam and sandy soil is negatively linear with the addition of water repellent. With the increase of water repellent degree, the field water holding rate decreased, the wilting coefficient was not significantly different, the gravity water increased, the available water and easy available water decreased, and the ratio of easily available water decreased with the increase of water repulsion degree. For water-repellent clay loam, the contents of micropores (0.3 ~ 5 渭 m) and small pores (5 ~ 30 渭 m) decreased obviously with the increase of water repellent degree, and soil voids (鈮，
本文编号：2393443
[Abstract]:In order to study the effect of water repellent degree on soil moisture characteristic curve, seven kinds of clay loam (L0~L6) with water repellent degree and six kinds of sand (S0~S5) with water repellent degree were manually configured based on drip penetration time method. The characteristic curves of soil moisture were measured by high speed centrifuge and fitted by van Genuchten-Mualem (VG) model. The hydraulic parameters of VG model were obtained. The results showed that under the same suction condition, the moisture content of water-repellent clay loam soil was higher than that of water-repellent sand soil, and with the increase of water repellent degree, the soil moisture content decreased with the increase of water repellent degree. The residual moisture content of water-repellent clay loam decreased with the increase of water repellent degree, but the residual moisture content of S0~S3 of water-repellent sandy soil was not different, while the residual moisture content of S _ 4 / S _ 5 decreased significantly. The logarithm of intake value of water repellent loam and sandy soil is negatively linear with the addition of water repellent. With the increase of water repellent degree, the field water holding rate decreased, the wilting coefficient was not significantly different, the gravity water increased, the available water and easy available water decreased, and the ratio of easily available water decreased with the increase of water repulsion degree. For water-repellent clay loam, the contents of micropores (0.3 ~ 5 渭 m) and small pores (5 ~ 30 渭 m) decreased obviously with the increase of water repellent degree, and soil voids (鈮，
本文编号：2393443
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