基于HYDRUS-1D的不同质地土壤入渗过程数值模拟

Numerical simulations of water infiltration for various soil textures using HYDRUS-1D

基于HYDRUS-1D软件,对不同土质(淤泥、粉砂壤土、砂质粘壤土)的灌溉方案进行了系统的数值实验,模拟灌溉结束时及灌溉结束24 h之后的土壤剖面含水量和土壤湿润锋的变化情况。结果表明:在不产生径流的情况下,灌溉结束24 h后土壤的含水量分布和湿润深度只与土壤种类和灌溉量有关,与灌溉速度无关;对透水性较好的土质,灌溉水分重分布明显,以粉砂壤土灌溉速率0.7 cm·h^(-1)和灌溉时间3 h为例,灌溉结束时和灌溉24 h后土壤湿润深度分别为9.2 cm和20.6 cm,有55.3%的灌溉水参加了水分重分布;土壤湿润深度与灌溉量之间存在线性关系,拟合直线的斜率介于5.15(淤泥)和5.95(砂质黏壤土)之间。

Quantifying water dynamics in soils is the basis for the rational water management in agriculture. In this study a systematic numerical investigation is carried out into the variations of soil water content and soil wetting depth after irrigation and 24 h after irrigation for various soil textures（ silt,silt loam,sandy clay loam） using the HYDRUS-1D software. Results show that both soil water content and wetting depth 24 h after irrigation are only dependent on soil type and irrigation amount,and are not affected by irrigation rate. The re-distribution of irrigated water in soil is evident for the soil with a good drainage capacity. In the case of irrigation rate of 0.7 cm·h^-1 and irrigation time of 3 h for the silt loam,the wetting depth immediately after irrigation and 24 h after irrigation is 9.2 cm and 20.6 cm,respectively,with the re-distribution amount up to 55.3%. There exists simple linear relationship between soil wetting depth and the total irrigation amount for various soils,and the gradient of the fitted equations ranges from 5.15（ silt） to 5.95（ sandy lay loam）. The results obtained from this study could have the potential to be used in optimal water use in agriculture.