Research On Water-Saving Irrigation Technique Development Model And Gravity Sprinkler Irrigation Application In Arid Areas Xinjiang

On the basis of the available research conducted inside the country, this thesis focused on zoning of the water-saving irrigation areas in Xinjiang, the appropriate development model for each zone, and the relevant issues of adopting gravity sprinkler irrigation in these zones considering the special natural conditions and the current agricultural practices in this arid region. The study results can provide scientific basis for development of water-saving irrigation technique and optimum allocation of water resources in the arid Xinjiang.According the production practice in Xinjiang, this study approach combined data collection with on-site investigation and on-site experiment with theoretical analysis. The research contents have following 5 components: 1) development model of water-saving irrigation technique in arid Xinjiang; 2) economic analysis and calculations for gravity sprinkler irrigation projects; 3) crop water requirement, irrigation scheduling and crop water production function; and 5) fertigation system development and its application experiment. The main findings are as follows:1. Based on the evaluation indexes of climatic characteristic, water shortage, irrigation type and topography of the irrigation districts, 6 water-saving zones were divided for Xinjiang, they are: 1) pumping and storage area of the dry Tu-Ha valley with water shortage; 2) water diversion and storage area of the dry Kunlun mountain northern side with water shortage; 3) water diversion, pumping and lifting area of the dry Tianshan mountain southern side with minor water shortage; 4) water diversion, pumping and storage area of the dry Tianshan mountain northern side with water shortage; 5) diversion and storage area of the dry valley plain with minor water shortage; and 6) diversion and storage area of the dry valley plain with abundant watersource. Reference evapotranspirations of major crops in each zone were calculated using the Penman equation.2. Based on the factors of climate and soil, groundwater and cropping, economic conditions and productivity, methods for selecting water-saving irrigation technique were proposed, and further the development model for water-saving irrigation technique in each zone.3. Based on the empirical equations used for calculating the cost of main and distribution pipes of gravity sprinkler irrigation project, equations for calculating.4. economical hydraulic gradient, pipe length and the minimum cost of the main pipe were derived through theoretical analysis and mathematical transformation.5. In reference to the design experience of a gravity sprinkler irrigation project in the State Farm Division 29, economic analysis was conducted for building a pressure release pool on the main pipe and empirical equations were proposed for selecting the optimum project area and the surface gradient.6. Through theoretical analysis and mathematical derivation, the relation between main pipe distribution and the cost was obtained.7. Through 3-year field experiment, mathematical models were established for yields of spring and winter wheat, soil wetness, designed irrigation depth and fertilization rate.8. Through 3-year field experiment, water production functions for rapeseeds and winter wheat were established.9. A gravity sprinkler fertigation device was developed and has been used in practice. It has been found more economical and effective in improving yield in comparison with manual fertilization and airplane application.