排盐补淡对滨海盐碱土壤盐分变化的影响

Effects of Salt Draining and Fresh Water Supplement on Salt Content Change of Coastal Saline Soil

为明确增加地下水埋深及补淡淋洗对滨海盐碱土的脱盐效果,以期为滨海盐碱土壤改良及水资源合理利用提供科学依据。以浅井排盐和灌溉水、降雨淋洗作为排盐补淡措施,在距排盐井不同半径处对地下水位和1 m土层含盐量进行测定,研究其在排盐补淡过程中的变化情况。研究表明,利用4 m左右的简易浅井可有效增加地下水埋深,抽水区域地下水埋深围绕排盐井呈现"V"型变化;排盐对中度和重度盐碱土1 m土层含盐量的影响存在差异,中度盐碱土表现抑盐、重度盐碱土有脱盐效果,且都随着抽提半径的增大,抑盐脱盐效果减弱;灌溉或降雨对盐碱土壤有脱盐作用,抽水腾出土壤水库容会提高土壤脱盐率,比仅灌溉或降雨分别高34.22%和17.53%,接近水量的灌水处理比降雨效果明显。综上所述,增加地下水埋深、腾空土壤水库容可以有效抑制盐碱土壤返盐并提高灌溉水、降雨等淡水洗盐效率,加大土壤脱盐效果。

The effect of increasing groundwater depth and leaching by fresh water on coastal saline soil was studied in order to provide scientific basis for the improvement of coastal saline soil and the rational utilization of water resources. Salt drainage from shallow wells, irrigation water and rainfall leaching were used as salt drainage and desalination measures. The groundwater level and soil salt content of 1m at different radii from salt drainage wells were measured to study the changes in the process of salt drainage and desalination. The research shows that the shallow well of 4 m or so can effectively increase the groundwater depth and the groundwater depth in the pumping area presents a “V” type change around the salt discharge well. There was a difference in the effect of salt drainage on the salt content of the soil layer of 1 m in moderately and severely saline soil. The moderately saline soil showed the effect of salt inhibition, while the severely saline soil showed the effect of salt removal. Irrigation or rainfall has desalination effect on saline-alkali soil, pumping out soil water storage capacity will increase the soil desalination rate, 34.22% and 17.53% higher than that of irrigation or rainfall only, respectively. The effect of irrigation treatment close to the water amount is more obvious than that of rainfall. To sum up, increasing the groundwater depth and emptying the soil water storage capacity can effectively inhibit the salinization of saline soil, improve the irrigation water, rainfall and other fresh water salinity washing efficiency, and increase the effect of soil desalination.