石膏对土壤水分入渗特性的影响

目的]分析石膏对土壤水分入渗特性的影响,以期为土壤入渗模型及石膏更好地应用于生产实际、土壤改良等领域提供科学依据。方法]采用室内一维土柱模拟试验,利用垂直一维入渗代数模型分析在施加石膏前期,其对土壤水分运动特性的影响。结果]在施加石膏前期,与对照组相比,随着石膏施量的增加,累积入渗量分别减小了10.2%,16.15%,30.73%和40.38%;入渗率分别减小了18.78%,21.07%,42.13%和54.82%;土壤剖面含水量显著降低。利用垂直一维入渗模型对土壤水分入渗资料进行分析可知,与对照组相比,随着石膏施量的增加,土壤饱和导水率逐渐减小,且分别减小了18.42%,36.84%,59.21%和75.00%;而非饱和土壤水吸力分配系数β与土壤水分特征曲线和非饱和导水率综合形状系数α无明显变化规律。预测值累积入渗量与实测累积入渗量之间的接近程度较高,相关性较好,且决定系数R2均在0.99以上,且均方根误差小于0.5,说明在施加石膏前期,其可以有效地削弱土壤的入渗能力,减少水分渗漏,降低入渗速率,而且还可以改变土壤水分的分布状况,且利用垂直一维入渗模型可以较好地分析石膏对土壤水分特征的影响。结论]石膏可以有效地降低土壤的入渗能力和导水特性。

Effects of Gypsum on Soil Water Infiltration Characteristics

Objective] The effects of gypsum on soil water infiltration characteristics were studied to provide basis for soil infiltration modeling and the application of gypsum in the fields of production practice, soil improvement and so on.Methods] An experiment using one-dimensional infiltration vertical soil column was conducted to test the influences of gypsum on the soil moisture infiltration characteristics.Results] The results indicated with increasing of gypsum content, the cumulative infiltrations were reduced by 10.2%, 16.15%, 30.73% and 40.38% respectively, and the infiltration rates reduced by 18.78% and 21.07%, 42.13% and 54.82% in the early stage of gypsum application. Moreover, soil profile water content decreased significantly too. The data of soil moisture infiltration were analyzed by the vertical one dimensional infiltration model. In the model, saturated hydraulic conductivities reduced by 18.42%, 36.84%, 59.21% and 75.00% respectively, while the changes of distribution coefficient and comprehensive shape coefficient were not obvious with the increasing of gypsum content. The cumulative infiltration was highly correlated with the measured cumulative infiltration, having a coefficient of determination(R²) over than 0.998, and root mean square error less than 0.5. So, this study indicated gypsum could not only be able to weak effectively the soil infiltration capacity and reduce water leakage, but also can change the distribution of soil moisture. The vertical one-dimensional infiltration model performed well in analyzing the influences of gypsum on soil water characteristics.Conclusion] Gypsum can effectively reduce the infiltration capacity of the soil and change the characteristics of water transmissibility.