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Experiments on drainage rule and soil desalination effect under mulched subsurface pipe drainage |
SHI Peijun1,2, LIU Hongguang1,2*, HE Xinlin1,2, LI Hong1,2, LI Kaiming1,2 |
1. College of Water and Architectural Engineering, Shihezi University, Shihezi, Xinjiang 832000, China; 2. Key Laboratory of Modern Water-saving Irrigation Technologies of Xinjiang Production & Construction Corps, Shihezi University, Shihezi, Xinjiang 832000, China |
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Abstract To investigate soil desalination effect and rules of subsurface pipe drainage in a saline-alkali field under drip irrigation mulched during irrigation process, a well-controlled experimental system was designed to simulate the soil desalination process and identify the effect of soil desalination under surface drip irrigation and subsurface pipe drainage conditions. Drainage and soil salinity distribution characteristics were analyzed by controlling irrigation time and quota and recording the water outflow time, drainage duration, drainage flow rate, drainage water mineralization level and soil salinity profile. The results show that the drainage velocity ultimately tends to be in the range of 1.5-3.5 L/h and the salinity of drainage varies in the ranges of 20-40 g/L after three irrigation leaching experiments. The desalination rates are as high as 85 % and 80.5 % in the 0-40 cm and 0-80 cm soil layers, respectively. The minimum salt rejection rates in the middle of two concealed pipes are 57.96%, 56.73%, and 69.29%, respectively, but the maximum salt rejection rates above the pipes are 71.73%, 73.34%, and 84.26%. The amount of salt discharged from the concealed pipes accounts for 28.9% of the total salt content in the 0-80 cm soil layer, and the rest of the salt is rinsed below the 80 cm soil layer.
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Received: 12 September 2018
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