【作者】 郭文聪；

【导师】 樊贵盛；

【作者基本信息】 太原理工大学 ， 环境工程， 2013， 博士

【摘要】 随着人口增长等因素带来的粮食安全压力越来越大,迫切需要在挖掘现有耕地资源潜力的同时,开拓新的土地资源以寻求新的粮食增长点,而对盐碱化土壤特别是原生盐碱荒地的开发利用是一条可行之路。文章基于原生盐碱荒地地下水位偏高这一客观存在,以利用当地有限的降雨资源为前提,通过渗水地膜这一新的农艺技术措施全面覆盖于原生盐碱荒地地表,利用其弹力阻水性限制表层土壤水分蒸发从而抑制盐分的表聚,利用其单向透水性实现降雨叠加淋洗以达到逐步降低耕作层土壤盐分的目的。与其他治理盐碱化土壤的方法相比,该思路的最大优点在于不消耗当地有限的可控淡水资源。因此,其研究成果对于开发利用盐碱荒地资源以增加耕地面积具有十分重要的实际意义,同时也可为丰富盐碱地治理理论提供一定的科学参考。论文研究取得的创新点包括：①原生盐碱荒地虽然在水分蒸发的拉动作用下表层土壤盐分不断累积,但是其含量是存在极大值的,这是因为地表干土层对盐分累积存在抑制作用、钠离子对土壤孔隙的离散使得盐分累积延缓、土壤剖面中的聚合型水分运动零通量面阻隔土壤运移、溶质势梯度下的扩散和弥散减小表层含盐量。②提出采用渗水地膜全面覆盖于待改良盐碱地并辅以控制地表径流田间工程措施的思路,地膜全面覆盖后可以避免雨滴直接击打,这就保持了表层土壤的原有结构,当间歇性降雨落入地膜之上后,雨水在土壤吸力的作用下透过地膜进入土壤中,使得表层土壤基质势接近零,在水势梯度的作用下水分向下层迁移,而土壤中的盐分就跟随水分向下层运动,在这种间歇性淋洗的反复作用下,耕作层土壤逐渐实现脱盐。③根据渗水地膜覆盖的特点将水盐运动分解成两个阶段,即地膜上有积水和无积水,有积水时土壤水分通量就等于地膜上水分的入渗量,无积水时土壤水分蒸发受到抑制可假定为零,可利用水分运移方程和溶质迁移方程对水盐运移过程进行联立求解,模拟计算成果表明该数值计算方法是可行的。当然,文章得出的结论和成果只是对原生盐碱荒地土壤水盐运移特征、渗水地膜覆盖土壤盐分积累和运移规律的初步探讨,其有待于进一步的验证和补充,提出的数值模拟计算方法也有待于进一步验证和实践。总体来说,渗水地膜覆盖改良原生盐碱荒地这一技术思路,可为北方干旱半干旱地区数以千万亩计盐碱荒地资源的开发利用与次生盐碱中低产田改良提供参考,它是一种以不消耗可控淡水资源为代价开拓土地资源的新方法和新思路。更多还原

【Abstract】 With pressure on food security bigger because of factors such as population growth, new land resources must be opened up to seek new point of grain growth, at the same, the existing cultivated land resources should be excavated, and the development and utilization of saline-alkali soil especially primary saline-alkali wasteland is a feasible way.Based on high underground water level in primary saline-alkali wasteland in the article, the water-permeability plastic film was comprehensive covered in primary saline-alkali wasteland surface as this new agronomic measures, through used the local limited rainfall resource. The surface soil moisture evaporation was limited by the elastic water resistance, and the surface salt accumulation was suppressed. The soil salinity of plough layer was reduced gradually by rainfall stack leaching using its unidirectional pervious. Compared with other methods of saline-alkali soil governance, the greatest advantage of ideas was that the locally finite controllability fleshwater resources are not consumed. Therefore, the research results have important practical significance for the development and utilization of saline-alkali wasteland resources to increase the area of arable land, but also could be provided some scientific reference for the rich soil management theory.The innovation points were studied in this article including that:①The salinity of surface soil was accumulated by the pulling effect of water evaporation in primary saline-alkali wasteland, but its content is maximum. The reasons were that the inhibitory effect of dry soil on surface to salt accumulation, the discreting action of soil pores by sodium ion to delay salt accumulation, the polymeric zero flux of water movement in soil profile to inhibit salt surface accumulation, the diffusion and diffusion in solute potential gradient to reduce surface salinity.②The method was put forward that comprehensive coverage of water-permeability plastic film to improve saline-alkali soil, then the field engineering measures were supplemented to control the use of surface runoff. The surface soil original structure could be kept, because the water-permeability plastic membrane mulching could avoid direct hit of rain. After intermittent rain falling film, water could through film into the soil in soil suction effect. Then, the surface soil matric potential closed zero. The moisture could migrate to the lower layer under water potential gradient effect, and the soil salt would follow the moisture into the lower layer. The plough layer soil would realize desalting under the repeat effect of intermittent leaching.③The water and salt movement was divided two stages according to the characteristics of the water-permeability plastic film mulching, which were having water and no water on plastic film. When water was on the film, soil water flux was equal to the amount of infiltration on the water. When water was not on the film, soil evaporation could be assumed to be zero because of suppressed. Then, the water and salt transport process could be solved by simultanenously soluted moisture transport equation and solute transport one. And the simulation results showed that numerical calculation method is feasible.Of course, the conclusion and results were drawn in the article that only discussion about soil moisture and salt movement feature, and soil salt accumulation and migration regularity of water-permeability plastic film mulching, and its conclusion should be verified and supplied further. The simulation calculation methods need to be further validated and practice. Overall, this method of water-permeability plastic film mulching improved primary saline-alkali wasteland could provide reference, for development and utilization of tens of millions acres of saline-alkali wasteland in the northern arid and semi-arid region, and for low-yield secondary salinization. It also is a kind of new method and ideas to development land resource which was not consumed controllable freshwater resources.更多还原