摘要
【目的】揭示滨海地区暗管排水下土壤水分和盐分的运移规律及脱盐效果。【方法】取山东省东营市垦利区盐碱地项目区的土样,通过室内土槽淋洗试验,模拟暗管条件下冬灌淋洗过程,分析不同土壤深度的含水率、电导率、离子量,暗管排水水质、排盐量,土壤脱盐效果及盐分占比。【结果】灌水初期,土壤渗水速率较快,3 h后湿润锋抵达20 cm土层深度处,随着水分向下运移,土壤盐分随水流向下迁移,且土壤渗水速率随土层深度增加而降低;停止灌水后,土壤上层水分继续下移填满地下水层后,地下水位上升至暗管底部1 cm处时暗管开始排水,排水持续61 h,总排盐量为1022.69 g。排水结束后,0~60 cm土层离子量显著降低,土壤脱盐率为67.5%~97.3%,其中Na^(+)、Cl^(-)分别降低74.47%~98.69%、94.73%~99.28%;60~80 cm土层因盐分积累呈负脱盐率(-67.80%)。盐分平衡分析表明,淋洗后0~60 cm土层脱盐量的去向主要为:地下水层(3960.99 g,占比60.96%)>暗管排盐(1022.69 g,占15.74%)>60~80 cm土层(811.57 g,占比12.49%)。水质监测显示饱和带土壤电导率(83.85~126.12 mS/cm)显著高于暗管排水(40.99~61.15 mS/cm),表明含水层中盐分滞留风险较高。【结论】暗管排水能有效调控地下水位并显著提升0~60cm土层的脱盐效果,但60 cm以下土层中盐分存在积累效应。建议采用“上层控盐-中层导排-下层防返”的分层治理方案,通过深埋暗管及间歇淋洗等措施进一步优化深层脱盐效果。本研究为滨海盐碱地暗管排水工程设计及节水控盐措施提供了理论依据和数据支撑。
【Objective】Coastal saline-alkali soils could cause severe damage to crop and reduce agricultural production.To understand the mechanisms underlying salt movement and develop mitigating strategies,we investigate water and salt movement,as well as the associated desalination in such soils under subsurface drain drainage.【Method】The experiment was conducted in soil columns.Saline-alkali soils taken from the Kenli District;Dongying City was used in the experiment.During the experiment,we measured the spatiotemporal dynamics of soil water,electrical conductivity(EC),ion contents,chemistry of the effluent,as well as soil desalination.【Result】①Water infiltrated fast during initial irrigation stage.As the waterfront moved downward,soil salt migrated with the flowing water into subsoils and infiltration rate subsequently decreased.②After irrigation stopped,water in the topsoil continued to move downward,resulting in groundwater table rise.Drainage started when groundwater table was level with the subsurface drain.③After drainage ended,ion content and salinity in the 0-60 cm soil profile decreased significantly,with Na^(+) and Cl^(-) contents decreasing by 74.47%-98.69%and 94.73%-99.28%,respectively,compared with their initial values;soil desalination in this layer was 67.5%-97.3%;the overall soil desalination in the 0-80 cm soil profile was 43.31%.④At the end of the experiment,there was a significant shift in salt redistribution in the 0-60 cm soil layer;1022.69 g of salt was leached out the soil via the subsurface drains,811.62 g remained in the 60-80 cm soil layer,and 3968.52 g moved into the aquifer below the subsurface drain.【Conclusion】Our findings demonstrates the effectiveness of the subsurface drain in redistributing water and salt in the soil profile and salt leaching out of soil through the drain.They can help design drainage system to remediate coastal saline-alkali soil and improve agricultural production.
作者
朱玉朵
王薇
黄乾
王锦龙
庞桂斌
ZHU Yuduo;WANG Wei;HUANG Qian;WANG Jinlong;PANG Guibin(School of Water Conservancy and Environment,Jinan University,Jinan 250022,China;Shandong Provincial Institute of Water Conservancy Science,Jinan 250013,China;Shandong Key Laboratory of Water Network Dispatching and Efficient Utilization,Jinan 250013,China)
出处
《灌溉排水学报》
2025年第12期66-75,共10页
Journal of Irrigation and Drainage
基金
山东省重点研发计划项目(2023CXGC00905)。
关键词
土槽淋洗
暗管排水排盐
水盐运移
脱盐率
soil trough leaching
subsurface drainage
water and salt transport
desalination rate
