干旱灌区灌水方式对田间土壤脱盐效果的模拟研究

Simulation Study on Desalting Effect of Field Soil derived from Irrigation Method in Arid Irrigated Area

为探究干旱灌区不同灌水方式下的田间土壤脱盐效果,通过构建基于HYDRUS-2D软件的土壤水盐运移模拟模型,模拟并分析了试验区土壤水盐的垂直运移过程和规律。结果表明,灌溉入渗对土体盐分的淋洗作用明显,灌水定额在4 000～6 000m3/hm2范围内的土壤脱盐效率较高;轮灌第一次的灌溉水量控制在使田间0～100cm土层含水率达到饱和即可,在后几轮灌溉过程中逐步增加灌水量的灌溉方案更有利于排出田间土壤盐分;在轮灌间隔为12d,轮灌次数为3次的条件下,灌水定额控制在5 200～6 000m3/hm2范围内的灌溉方案可使田间0～100cm土层含盐量达0.98%～1.13%,满足设计含盐量为1.2%的脱盐标准,达到设计干旱灌区脱盐灌水制度的目的。模拟结果可为干旱灌区的水土资源保护和可持续利用提供决策依据。

In order to study the desalting effect of field soil under different irrigation methods in arid irrigated district,the water and salt movement simulation model based on HYDRUS-2Dis established to simulate and analyze vertical water and salt transport processes and laws of testing zone.The results show that leaching effectiveness of soil salinity derived from irrigate infiltration is obvious,and desalinization efficiency is relatively high when irrigation quota is 4 000～6 000m3/hm2.The irrigation scheme that first irrigation amount is controled in reaching saturated water content of 0～100cm soil layer and subsequent irrigation amount is increased gradually to make the field soil desalt more easily.Under condition of 12 days,rotational irrigation time interval and 3rounds,the scheme that irrigation quota was controlled within the range from 5 200 to 6 000m3/hm2 would make the 0～100cm soil layer salinity reach 0.98%to 1.13%to satisfy the standard of desalination whose designed salinity is 1.2%,and achieve the aim of designing salt leaching irrigation regime in arid irrigation area.Simulation results can provide decision-making basis for farmland soil and water resources protection and sustainable utilization of irrigation area.