Study On The Simulation Of Water-Salt Dynamic And The Optimal Drainage Model In The Northwest Drought Region

Improving the production capacity of land, utilizing the land of salinization, and preventing the soil secondary salinization, have already become one important respect of the sustainable utilization of land resources and agricultural development. With the project of the National Natural Science Foundation of China(NSFC), "Multi-criteria optimal aiming to meliorate the salt land and drain in the northwest drought region", applying some domain knowledge, such as the water-salt movement of the groundwater and soil water, farmland draining, water resources, water environment, system engineering, computer technology and so on, this paper studies the principle of water-salt movement and the design of the farmland drain in-depth, which establishes good foundation in the research of the improvement salt soil and the preventing of the soil secondary salinization. It has important theoretical and practical meaning.The whole paper consists of six chapters, and the chief substances of each chapter are shown as follows.Chapter 1 connects with the reality, analyses the meaning and application prospect of the paper, reviews domestic and international research dynamic status and trend on water-soil movement and salt soil, and points out the goal and main content in this paper.Chapter 2 introduces the basic situation of the Shulehe region, and analyses the reason why the salt and alkaline land forms.Chapter 3 analyses and studies the water-salt dynamic experiments.Chapter 4 sets up two-dimensional water-salt transporting equation of soil, simulates and calculates with the numerical method, then using the result contrasts and validate with the data which has measured.Chapter 5 regards the saturated infiltration coefficient as the random variable, makes stochastic modeling of water-salt movement in the soil.Chapter 6 layouts and designs the drainages of open ditches, sub-drains and shaft by controlling the groundwater table with various kinds of methods. And it set up an optimal drainage model for prevent of soil salinization.Chapter 7 summarizes the research of the paper and lists some topics and problems which need studying farther more.