宁夏盐碱地改良暗管排水脱盐效果研究

Research of Desalting Effect of Improved Underground Drainage Pipe in Saline-Alkali Soil of Ningxia

为评价宁夏河套灌区暗管排水技术改良盐碱地效果,选取5个典型暗管排水区,连续2 a对该区土壤中的盐分、地下水位、地下水质、作物种植效果等进行观测,分析水盐动态变化规律,对暗管排水技术的实施效果进行研究,提出盐碱地治理中暗管排水技术标准.结果表明,暗管排水区在春灌前至停水后,0~20 cm土层的脱盐率为3.4%~83.1%,平均脱盐率为43.2%;20~80 cm土层的脱盐率为10.0%~71.2%,平均脱盐率为40.6%.春灌前、作物生育期间、初冻期的地下水位应分别控制在1.6~1.8,0.8~1.4,1.2~1.5 m.

In order to objectively evaluate the effect of salinity improvement by concealed pipe drainage in Ningxia Hetao irrigation area,this paper proposed key technical parameters&indicators for construction and operation management of concealed pipe drainage project.In this paper,five typical concealed pipe drainage areas were selected,and the salinity in soil,groundwater level,groundwater quality,and crop planting effect were observed for 2 consecutive periods,the water-salt dynamic changes were analyzed and studied,and the effect of implementing the key technology of dark pipe drainage was studied to propose the technical standard of dark pipe drainage for saline land management in the study area.The results showed that the desalination rate of the 0-20 cm soil layer ranged from 3.4%-83.1%,with an average desalination rate of 43.2%;and the desalination rate of the 20-80 cm soil layer was from 10.0%to 71.2%,with an average desalination rate of 40.6%,from before spring irrigation to after water stoppage in the dark pipe drainage area.The soil groundwater level should be controlled at 1.6-1.8 m,0.8-1.4 m and 1.2-1.5 m before spring irrigation,during crop fertility,and during the early freezing period,respectively.