复杂土壤分布特征及暗管排水响应模拟

Distribution characteristics of complex soil and response simulation of subsurface drainage

盐碱地中障碍土层的存在可能会导致排水工程无法充分发挥其应有作用,这对其治理提出了很大挑战。以宁夏回族自治区红寺堡为研究区域,实地取样调查了不同点位的复杂土壤分布特征,基于HYDRUS二维模型分析了不同黏土层位置对于暗管排水流量的影响作用,并提出复杂土壤条件下的排水建议。结果表明,土壤存在弱透水层且无其他治理措施时,土壤盐分普遍偏高,弱透水层的位置不具有固定位置和特征,总体来说,弱透水层厚度以10~20 cm偏多。当黏土层位于暗管层时,10 cm黏土层就会导致暗管排水量减少20%,暗管上部10 cm位置处的黏土层对于暗管排水效果影响最大,较常规地下排水量减少22%;当黏土层位置超过2倍暗管埋深时,对于暗管排水量的影响较小。根据不同弱透水层的位置,合理设置排水排盐方式对盐碱地改良具有重要意义。

The existence of barrier soil layer in saline-alkali land may cause that the drainage project can not play its role which also poses a great challenge to the its treatment.Hongshibao,Ningxia Hui Autonomous Region was taken as a typical area.The distribution characteristics of complex soil in different plots were investigated based on field sampling,the drainage effect of different location of clay layer on discharge of subsurface drainage were analyzed based on the simulation of HYDRUS 2D,and the suggestion for drainage under complex soil conditions was put forward.The results showed that when the soil has weak permeable layer without treatment measures,the soil salinity of the land was generally high.The location of the weak permeable layer does not have a fixed position and characteristics,the thickness of the weak permeable layer was usually 10-20 cm.When the clay layer was located at the pipe layer,10 cm of clay layer leads to a 20%reduction in the discharge of the subsurface drainage.The effect of the clay layer located at 10 cm soil layer above the pipe on the discharge was the largest with a 22%reduction than conventional subsurface drainage.While when the clay layer was located at the depth of double pipe depth,the effect of clay layer was small.According to the location of weak permeable layers,a reasonable drainage and salt drainage method was of great importance to the improvement of saline-alkali land.