Studies on Effective Desalinization Methods from Soils

在本研究中，我们提出了两种改善盐碱地脱盐的策略。一种是在浸出前进行土壤干燥，另一种是混合土壤改良剂来稳定渗透孔。在内蒙古河套灌区盐渍土、小岛湖底泥、艾萨哈雅圩田土和河套灌区土壤上对这两种策略进行了试验。研究了土壤干燥促进盐溶解的机理，重点研究了土壤基质的空气软化。盐在土壤基质表面的积累不仅促进了盐的溶解，而且由于土壤干燥，通过稳定的土壤结构增加了盐的扩散系数。实验结果表明，盐的最大溶解度在空气溶解度的最大含水量处。土壤干燥到含水量最大时，空气发生的熟化效果最好。已知在浸出过程中，渗流孔隙被测井，浸出效率下降。加入土壤改良剂，通过稳定渗透孔来提高水力导电性。在土壤改良剂中，有机堆肥和炭化剂效果最好。由于艾萨哈雅土的膨胀性和分散性，艾萨哈雅土的效果比河套土小。石膏对维持水导率和挤压钠均有显著的作用。通过连年的田间研究，发现土壤干燥特别是全倒耕对艾萨哈雅圩田的脱盐和土壤成熟非常有效。通过河套灌区的田间试验，对表土挤压法、排沙法和施石膏法进行了试验，并评价了其有效性。

In this study, we made two strategies for improving desalinization of saline soils. The one is applying soil drying before leaching and the another is mixing soil amendments for stabilizing percolating pores. The two strategies were examined on saline soils, the bottom mud of Kojima lake, Isahaya polder soil and soil of Hetao Irrigation District, Inner Mongolia.Mechanism of promotion of salt dissolution by soil drying was studied with special attention to air slaking of the soil matrix. Salt dissolution was promoted not only by salt accumulation to the surface of soil matrix but also by increasing salt diffusion coefficient through stabilized soil structure due to the soil drying. The experimental results showed the maximum salt dissolution at the water content of the maximum air slaking. Soil drying to the water content of the maximum air occurred slaking was found to be the most effective.It is known that the percolation pores are logged and leaching efficiency decreases in course of leaching. Soil amendments were added to improve hydraulic conductivity by stabilizing percolating pores. Among the soil amendments tested, the organic compost and the crashed charcoal were found most effective. The effectiveness was small on the Isahaya soil than the Hetao soil, because of swelling and dispersive properties of the Isahaya soil. Gypsum showed remarkable effect both on maintaining hydraulic conductivity and on extrusion of sodium.Soil drying practice, in particular, full upside down plowing was found to be very effective on desalinization and soil maturing of the Isahaya polder through successive yearly field research. Surface soil extrusion method, sand drain method and gypsum application method are tested and their effectiveness was evaluated by field test in Hetao Irrigation District.