磁化微咸水及石膏改良对土壤水盐运移的影响

    Effects of magnetized saline water and gypsum amelioration on soil water-salt movement

    • 摘要: 为了探究磁化水和石膏共同作用对水盐运移特征的影响,该研究通过室内一维垂直入渗试验,分析未磁化和磁化微咸水两种类型的灌溉水入渗下,5个石膏施量(0、0.1、0.2、0.4、0.6 kg/m2)对土壤水分和盐分运移特征的影响。结果表明:磁化和未磁化微咸水入渗时,累积入渗量和湿润锋深度均随着石膏施量的增加而减小。不同石膏施量的磁化微咸水最终累积入渗量与湿润锋深度减小,土壤含水率比未磁化微咸水提高了11%~14%。相对于未磁化微咸水,磁化微咸水降低了土壤水的入渗速率,减缓了湿润锋运移速度。磁化微咸水入渗下,施加石膏降低了Philip入渗模型吸渗率,显著提高了脱盐率和脱盐效率。磁化微咸水入渗下,石膏施量为0.4 kg/m2时,与未磁化相比,磁化微咸水的土壤储水量增加了14.9%。石膏施量为0.4 kg/m2时淋洗效果最好,脱盐率提高了59%。可见,磁化微咸水入渗和石膏改良显著影响土壤的持水性和脱盐效果。研究可为灌溉水高效利用和盐碱地改良提供参考。

       

      Abstract: Saline water has been widely used to alleviate the freshwater shortage during agricultural production in arid and semi-arid regions. However, continuous saline water irrigation can easily lead to soil salinization, even soil degradation, and reductions in crop yields. It is critical to select the appropriate water treatment and soil amendment for sufficient water, but less accumulation of salinity in the soil. In this study, the magnetized saline water and gypsum ameliorate were served as the ecologically pure, safe, and simple treatment on soil water-salt movement. One-dimensional vertical infiltration experiments were conducted to investigate the infiltration with/without magnetized saline water into the saline soil with different gypsum applications. Five gypsum application (0, 0.1, 0.2, 0.4, and 0.6 kg/m2) were used. The results showed that the cumulative infiltration and the depth of wetting front decreased, with the increase of gypsum application with/without magnetized saline water. There was a significant decrease in the final cumulative infiltration and the depth of wetting front of magnetized saline water for different gypsum applications. The cumulative infiltration of magnetized saline water decreased by 14.9%, 10.9%, 9.5%, 8.0% and 8.9%, respectively, under five gypsum application of 0, 0.1, 0.2, 0.4 and 0.6 kg/m2, compared with non-magnetized saline water. The cumulative infiltration of 0.1, 0.2, 0.4, and 0.6 kg/m2 application amount for non-magnetized saline water treatments decreased by 9.8%, 13.3%, 17.1% and 21.5%, respectively, compared with the control (0 kg/m2), whereas, those decreased by 5.6%, 7.8%, 10.4% and 16.0%, respectively, in magnetized saline water treatments. The sorptivity of magnetized saline water decreased by 24.4%, 22.7%, 19.1%, 19.1%, and 19.2%, respectively, under the five gypsum applications, compared with non-magnetized saline water. The soil water content decreased, as the depth increased for the saline water. The soil water content of magnetized saline water increased by 12%, 11%, 14%, 14%, and 11%, respectively, compared with the non-magnetized saline water. There was the highest soil water storage for 0.4 kg/m2 gypsum application under magnetized saline water irrigation, which was 14.9% higher than that of non-magnetized saline water. The depth of the desalination zone increased firstly and then decreased, with the increase of gypsum application amount. The soil salinity content of magnetized saline water decreased by 48.8%, 28.7%, 37.5%, 29.1%, and 60.0% at 20cm soil depth, respectively, compared with non-magnetized saline water, indicating that the magnetized saline water decreased the infiltration rate of soil water and the transport speed of wetting front. The gypsum can be used to reduce the soil sorptivity of the Philip equation, but to significantly increase the soil desalination rate and efficiency. There was the highest desalination efficiency for the 0.4 kg/m2 gypsum application, where the desalination rate increased by 59%. Thus, the magnetized treatment and gypsum application can serve as an effective way to improve soil water retention and enhance desalination salt leaching. This finding can provide theoretical support to efficiently utilize the irrigation water in the saline-alkali soil.

       

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