【作者】 杨树青；

【导师】 史海滨； 陈亚新；

【作者基本信息】 内蒙古农业大学 ， 农业水土工程， 2005， 博士

【摘要】 淡水资源的短缺和工业用水的竞争,使农业生产对劣质水(咸水或城市污水)利用的依赖性日益增加。劣质水利用带来的环境问题成为目前研究的热点和前沿课题。其中水—土环境是灌溉农业科学中最为活跃的组成部分,是治理土壤盐渍化的核心。本研究揭示了微咸水灌溉对作物生理、土壤环境和地下水环境的影响规律。探讨干旱-半干旱地区微咸水灌溉的水-土环境效应预测评估研究。研究将对水资源日益短缺的河套灌区有着重要意义,并可为类似地区提供参考。 研究引进了世界上公认的模拟三维地下水流和溶质运移的 Visual MODFLOW (VMOD) 模拟系统和模拟水、溶质和热在土壤—大气—作物环境中运移过程的 SWAP模型。从而将饱和带和非饱和带构成一个完整体系对微咸水灌溉的水土环境效应展开预测评估研究,全面深入地探讨和论证了微咸水开发利用的可行性。 一般在利用 SWAP 模型预测时,存在着下边界条件难以确定的难题。本研究成功地将 VMOD 模型模拟预测的地下水位运用于 SWAP 模型的下边界。使 SWAP 模型的应用更具准确性。在研究中首次将 VMOD 与 SWAP 模型耦合,构成一个耦合体后用于对微咸水灌溉的水—土环境效应的预测模拟。 VMOD 目前多用于地下水流的模拟,对地下水质的模拟较少报道。研究尝试采用 VMOD 中的 MT3DMS 模型对地下水质进行了模拟预测并指出了其应用中的局限性。 SWAP 是垂直一维水盐运移模型。不同的水文地质条件应具有不同的 SWAP 模型。研究运用地质统计学理论,对研究区的土壤水盐信息进行了空间结构性分析,并以此为依据对研究区进行了分区。有效地将地质统计学理论与 SWAP 模型联合应用,避免了通常仅采用一种 SWAP 模型过度简化的粗略性。 研究中连续的田间灌溉试验、常规和专门观测、野外室内实验进行有关参数的测定和边界条件的详细论证确定,为 VMOD 和 SWAP 系统在本研究区的应用及保证预测结果的可靠性奠定了坚实的基础。 作物耐盐度研究发现灌溉水浓度达到某一临界值时,盐分在一定深度的土层内聚集明显增大。这一临界浓度值与使作物生长、产量受到抑制的灌水浓度基本一致,且不同作物的临界灌水浓度值不同。研究还揭示了淋洗灌溉定额下作物的耐盐能力增大,由于较大定额的淋洗灌溉将盐分淋洗到深层,在排水作用下从土层中排出,使作物根区盐分降低。应用产量与灌水浓度的相关关系预测出研究区 3 种主要作物的耐盐度阈值分别为两种灌溉定额下小麦的耐盐度为 4.5g/l。正常定额下玉米在的耐盐度为3g/l,葵花为 5g/l。淋洗定额下玉米的耐盐度为 3.5g/l,葵花为 7g/l。预测值与研究发现的灌水浓度临界值基本吻合。 平均年法和考虑时间序列法两种预测方法得出了基本接近的结果,平均年法在进更多还原

【Abstract】 Because of the shortage of fresh water and the competition of the industry, it increasingly depends on the pool-quality water (saline water or city sewage) in agriculture produce. The environment problems caused by the pool-quality water utilization has becomed the hot topic and forward position task in the research field, and the soil-water environment is the most activest component of the irrigation agriculture and is the core of governing the salinization. This research reveals the laws that saline water irrigation influeces the crop physiological indicator, underground water level, underground water quality and soil salt, etc. This research also predicts and evaluates the effect of soil-water environment caused by the light saline water irrigation in the arid and semi-arid region. It is important and meanful for the Hetao Irrigaiton District where the water resource is decreasing, and it can provide consultation for similar districts, as well. The research includes the three-dimensional groundwater movement and solute transport simulation system Visual MODFLOW that has gained the worldwide approval, and the SWAP model which simulates soil water movement, solute and heat transport in the Soil-Atmosphere-Plant System in this paper. Thus the saturated and unsaturated zones construct one whole system. The soil water environment effect introduced by light saline water irrigation is forecasted and researched, and the feasibility of light saline water utilization is proved fully. The VMOD model and SWAP model are firstly coupled and used in this paper. Until now, VMOD is mainly used in the groundwater movement simulation, and it is few used to simulate groundwater quality. This paper tries to apply the MT3DMS model of VMOD into forecasting groundwater quality and to point out the limitations. SWAP is one dimensional vertical water salt movement model, and there are different SWAP models in different conditions. In this paper, the Geostatistics is used to analyze the spatial construction of soil water salt information in the researching district. Based on the analyzing results, the research district is divided into two small parts. Therefore the Geostatistics theory and the SWAP model are coupled successfully, where it avoiding the subjectivity of using one SWAP model in one district. Successive field irrigation experiments, special and conventional observations, the related parameters observed in the field and the boundary conditions determined, all these above provide the solid basis for applying the VMOD and SWAP system into this research. In the research of crop resistance capacity to salt, it is found that the soil salinity increases obviously in the definite deep zone when the salt concentration of irrigation water reaches the critical value. This critical value is basically coincided with the salt concentration of irrigation water that restrains the crop growing and decreases the crop yield. Different crops have the different critical concentrations of irrigation water. In the research, it is also found that the resistance capacity to salt is enhanced through leaching irrigation. Leaching irrigation can leach salt into deep layer while drain salinity from soil layer. As the result, the soil salinity in the root area is decreased. By establishing the correlation between yield and salt concentration of irrigation water, the thresholds of salt tolerance for three main crops are determined. The salt tolerance threshold of wheat in two kinds of irrigating quota is 4.5g/l. In the normal quota, the salt tolerance threshold of maize is 3g/l, and it is 5g/l for sunflower. In the leaching quota, the salt tolerance threshold of maize is 3.5g/l, and it is 7g/l for sunflower. The predicted value is basically accordante with the factual value. The result predicted by the method of average year is accordante with the result predicted by the method of considering time array. The method of average year is a simpler method in predicting tendency. The simulated results show that the salt in the high mineral zones更多还原