Research On The Critical Technology Of Border Water-saving Reform And Irrigation Decision-making In Hetao Irrigation District

The surface irrigation technology is used in percentage of 95 irrigated area in the whole world, and the traditional surface irrigation is main in HeTao irrigation district in Inner Mongolian, so it's important to study on key technology of border water-saving re-building and irrigation decision-making with increasing contradiction of water resources supply and demand, continuous readjustment of planting mode and structure in this region.Aiming at above question, SIRMOD model simulating surface irrigation was intro-duced in this paper, and the critical parameters such as soil infiltration parameters, surface parameters, border sizes, and so on were studied through this model; ISAREG model with function of evaluation and optimization was used to research on irrigation schedules of food crops under different planting mode and cash crops considering irrigation technology condition; SADREG model with function of decision support system was used to research on irrigation decision-making. Main research findings including:(1) The soil infiltration parameters of wheat and maize border are separately calcu-lated by SIRMOD, Maheshwari, Esfandiari, non-linear return and linear return model, the results indicating: the precision of SIRMOD and non-linear return model is higher with less observation data and few work; the soil infiltration parameters are gradually reducing with increasing irrigation times, in which the influence of first irrigation to infiltration parame-ters is most greatest, the infiltration coefficient of second irrigation is lower approximately 5.0%~11.0% than first irrigation and infiltration index reduced about 5.0%~15.0%, infiltra-tion capability is gradually stabilizing in third irrigation, and the influence of irrigation to silt is larger than silty loam.(2) The irrigation efficiency is separately calculated by SIRMOD, SRFR model and field measurement method in wheat and maize border sizes, the results indicating: the pre-cision of the SIRMOD model is highest; The crop yield and efficiency of water application increase by improving irrigation efficiency under the same border sizes and irrigation quota, However, irrigation efficiency improvement isn't obvious with border wide enlarging and irrigation quota increasing, and the water use efficiency reduce obviously, therefore it is necessary to reduce the sizes of larger border; According to the comparison results of irri-gation efficiency, it can be suggested that the border sizeâ… (length is 45.0m and wide is 5.0m)andâ…¡(length is 45.0m and wide is 7.5m)should be adopted, while considering pre-sent farming level, the application of 1.0mu border(length is 45.0m and wide is 15.0m) should be decreased, and 1.5mu or lager border should be restricted.(3) The simulation results of SIRMOD model for various factors of influencing to ir-rigation efficiency indicates: land leveling precision is obviously influencing to water movement and regression, and lower leveling precision can obtain better irrigation effect, so the laser controlled land level should be advocated; the land roughness's influence on process of water movement and regression are larger, and the course of water movement and regression of lower land roughness is more perfecter. With increasing of land rough-ness, process of water movement and regression change into scraggly curve and irrigation efficiency has dramatic decline; irrigation quantity and flux per width also influenced on the irrigation effect significantly, irrigation uniformity can be improved by increasing irri-gation quantity, meanwhile, irrigation efficiency decrease, and irrigation efficiency can be reformed through enlarging flux per unit width. However, it's not that the more lager flux per, the more higher irrigation efficiency, but different conditions is corresponding to dif-ferent flux per width; different irrigation factors and field parameters are corresponding to different optimum field surface slope, so the better irrigation efficiency can be obtained along with appropriate slope, The optimum slopes of different field sizes on condition of the conventional and laser- controlled land technology can be concluded by the SIRMOD model simulation. According to the simulation results, it is suggested that length of border should be controlled between 45~60m and the width less than 10m.(4) In this paper, several parameters which ISAREG model needs were verified and the actual irrigation schedules of crops were evaluated, then multi- irrigation schemes were designed for various crops. According to the simulation results, wheat's optimizational ir-rigation schedule in border irrigation under condition of present water supply and irrigation dates without constraint to Yellow River incoming water, tomato's in border and furrow irrigation and pepper's in furrow and separate furrow irrigation considering constraints of surface irrigation technology and the wheat interplanting sunflower's and the wheat inter-planting maize's considering planting mode was concluded.(5)According to the optimizational results of various parameters based on SIRMOD and ISAREG model, Multi-objective analysis and evaluation were made for thirteen schemes of wheat border irrigation by employing SADREG model, and it can be concluded the tenth(length is 45.0m and wide is 7.5m) was the most perfect through comparing and analyzing the performance indexes of benefit, cost and environmental effect and taking the total utility function value as the standard, and the optimally irrigation decision-making scheme of wheat can be obtained by combining with optimized surface parameters and ir-rigation schedule of a correspondence.