黑河中游绿洲不同质地土壤水分的入渗与再分布

该文利用双环入渗仪,通过定水头法研究了黑河中游绿洲地区玉米地和防护林地土壤水分的入渗过程,并利用Hydrus-1D模型和Trime-IPH手持式TDR分别对土壤水分的入渗和再分布过程进行了动态模拟和测定。结果表明:不同质地土壤水分入渗和再分布差异明显。土壤下部粘土夹层不仅对水分入渗起到显著的阻碍作用,而且具有较强的持水保水能力。统计分析表明,试验期间模拟土壤含水量的均方根误差和相对误差分别在0.02cm3/cm3和0.68%以下,模拟剖面储水量的均方根误差和相对误差分别在0.908 cm和0.9%以下,因此Hydrus-1D模型对绿洲地区土壤水分在垂直方向的运移模拟具有较高的精确度,这为该区域水分管理和可持续发展提供理论依据。

Infiltration and drainage processes of different textural soil moisture in middle reaches of Heihe River Basin

Abstract: Heihe River irrigation region is typical arid agricultural oasis. It is also important commodity grain, cotton and oil-producing areas. Water shortage is a key issue of limiting socio-economic development. Flood irrigation is still the main irrigation methods about agricultural production and they believe that a large number of farmland irrigation result in high crop yields. This approach not only reduces water use efficiency but also wastes a lot of valuable water resources. Therefore, investigating soil moisture movement laws has important theoretical significance and practical value for the agricultural water-saving irrigation. Although many related results for infiltration and drainage of soil moisture have been reported in previous literature, most of the studies have been focused on the Loess Plateau, red soil area of South China and karst area of Southwest China, few on arid oasis area. The double-ring infiltrometer is used to measure infiltration by the constant-head method, composed of inner-ring and outer-ring whose diameters are 80cm and 100cm, respectively. Representative position in the maize farmland and protection forestland was chose, and the Trime Tube depth of 275 cm and 265 cm was installed, respectively. The double-ring was embedded in soil and the water depth of the inner and outer-ring was 5 cm. Soil water content of infiltration and drainage processes was measured by Trime-IPH TDR and soil water movement was simulated accurately by Hydrus-1D model. Results of the simulations indicated that the soil textures significantly affected water infiltration and drainage. The finer grained layer was capillary barriers for water infiltration and drainage as well as had strong water holding capacity. The statistical analysis indicated that root mean square error (RMSE) and the relative error (RE) between the measured and estimated soil water content were below 0.02 and 0.68%, respectively. Root mean square error (RMSE) and the relative error (RE) between the measured and estimated soil water storage were below 0.908 and 0.9% respectively. HYDRUS-1D model had a high precision for the simulation of water transport of the oasis soil in vertical direction. The results can provide a scientific basis for water management and sustainable development of Heihe River Basin.