【摘要】 为了探索暗管排水条件下膜下滴灌农田的水盐运移规律,本文设计了埋深1 m,间距4 m的暗管排水模型试验,研究分析灌水淋洗过程中土壤水分和盐分的动态变化规律,并利用HYDRUS模型对暗管排水条件下的水盐运移规律进行数值模拟分析与验证。结果表明:经过3次灌水淋洗后,表层0～20 cm土层内盐分含量下降至2 g·kg^-1,达到了非盐化土水平,20～60 cm土体内上层土壤脱盐效果高于下层,总盐分含量下降至8 g·kg^-1以下;经过实测值与模拟值的验证,土壤盐分和水分的均方根误差RMSE最大分别为0.632和1.324,决定系数R²最小分别为0.992和0.906,说明模拟结果与实测结果吻合度较好,HYDRUS模型能够较好地模拟暗管排水过程中水盐运移规律。通过模型模拟6次灌水（共90 d）后暗管排水条件下不同土层深度的水盐动态变化特征,模拟结果表明,0～40 cm土层内盐分含量下降至2 g·kg^-1,40～80 cm土层内盐分含量下降至4 g·kg^-1左右,基本达到轻度盐化水平;距离暗管不同间距处的土壤剖面盐分含量呈波动变化,距离暗管越远,土壤剖面含盐量越大,盐分含量在0～8 g·kg^-1范围内变化。更多还原

【Abstract】 To explore the transport of water and salts of underground pipe drainage under mulch-drip irrigation system,we conducted an experiment with underground pipe drainage system of a 1 m deep and 4 m spacing pipes. The dynamic changes of soil moisture and salinity were measured during irrigation and leaching, and the transport was analyzed and verified with HYDRUS numerical model under the condition of subsurface drainage. The results showed that after three times of irrigation and washing, the salt content decreased to 2 g·kg^-1 in 0～20 cm soil layer, reaching the level of non-salinized soil. The effect on upper layer desalination was greater than that on lower layer soil of 20～60 cm, and the total salt content was less than 8 g·kg^-1.Through verification of the measured and simulated values, the maximum RMSE of soil salinity and moisture were 0.632 and 1.324, and the minimum values of R² were 0.992 and 0.906, respectively, which indicated the simulation results were in good agreement with the measured results.The HYDRUS model was more reliable to simulate the transport of water and salt in the subsurface drainage system.The dynamic characteristics of water and salt in different depths of soil layer under the subsurface drainage after irrigation for 6 times（90 days） were simulated by the model.The simulation results showed that the salt content was decreased to 2 g·kg^-1 in 0～40 cm soil layer, reaching the level of non-saline soil.The salt content in 40～80 cm was decreased to 4 g·kg^-1, which basically reached the level of slight salinization. The salt content in the soil profile fluctuated with distances from the pipe. The greater the distance from the pipe, the greater the salt content in the soil and the salt content varied within the range of 0～8 g·kg^-1.更多还原