Development And Application Of Non-full Irrigation Management Information System For North Areas

Water resource shortage is one of problems that affect human being, and China is one of 13 countries with serious water lack, which is very severe in north China. Distribution of water resource isn't proportional in time and space, such as arable area of north region being 64 percent of China but water resource being 19 percent. At the same time, there are exiting problems at large, such as lowness of water use efficiency and waste of water use. Under this condition, by scientific exploitation and management of limited water resource and by developing water-saving irrigation, the situation of water resource lack would be relieved, therefore guarantee sustainable and stable development of agriculture production. The purpose of development of non-full irrigation management information system for north areas, including propagation of water-saving, query of data, measuring water of irrigation district, crop evapotranspiration and irrigation method, and non-full irrigation decision, is to publicize water-saving, let people know extent of water resource lack and crisis of water, save using water, direct water-saving irrigation. The system shows the users with visual interface, friendly and succinct form, definite meaning of parameter, easy operation. The basic frame and development of the system use visual basic 6.0 language, specific contents of the paper including: 1) The subsystems, including propagation of water-saving, query of data, measuring water of irrigation district, are showed by word, picture, chart, and PowerPoint, and all controls of VB toolbox were almost used. The subsystem of water-saving propagation includes water-saving description of report of sixteen people representative commission and water laws of P. R. China, attention of every era leaders, and general knowledge of public water-saving. The subsystem of query of data includes water resources of North, crop demand for water and amount of irrigation, change and forecast of irrigation area, and change and forecast of agricultural water supply. The subsystem of measuring water of irrigation district supplies flux and water expense calculation about common ten kinds of special weir and trough for north irrigation district, showing the users with word and picture; When there are errors of operation, prompts would be appeared, which could help the ordinary application of technician and farmer. 2) The system provides calculation of crop evapotranspiration and irrigation quota, and introduces many irrigation methods. With FAO irrigation and drainage series books 56th part Penman-Monteith formula, computation program of ET0 had been developed about day and month as time unit, and ET value would be known while giving crop coefficient Kc. Irrigation quota might be computed by inputting parameter of interface requirement. Irrigation methods and techniques could be showed by word, picture, chart and PowerPoint. 3)With crops water-production function Jensen multiplication model and Stewart addition model as objective function, optimal irrigation scheduling system about winter wheat, spring wheat, cotton and summer maize has been established by means of dynamic programming and linear programming, being able to solve the problem that how to distribute water on the growing phases. As long as inputting related parameters, there would be a suitable optimal irrigation scheduling adaptable to different regions and different crops. It is easy to operate and may be popularized. Priority of irrigation should be given to the periods of critical crop water requirement, after the periods being satisfied, next water requirement period would be considered, turn to next. For example, periods of jointing to heading, heading to milking, milking to mature are critical water requirement periods for spring wheat at Gulang, Gansu. While allocation water 600 m3·hm-2, the quota of irrigation is 150,300,150 m3·hm-2 at the three phases. The system might direct allocation of water amount on the basis of time in order to make relative output maximum, and therefore least reduction of output. For instance, while allocated water 300 m3·hm-2 for cotton at Linfen, Shanxi, water supply would be 150 m3·hm-2 at blooming to belling and belling to wadding, and reduction of yield was 432.8 m3·hm-2. Using figure about allocated water supply and relative yield, ones may gain optimal relative output of any allocated water supply within full irrigation scheduling. Comparison about relative yield of computation and measure was made about winter wheat, at Jinzhong, Shanxi, and the result shows that maximum relative error was 12 percent and minimum 0.9 percent. Maximum relative error was 2.3 percent for summer maize at Xiaohe, Shanxi. 4) Comparison of crop water-production function had been made about Jensen multiplication model and Stewart addition model. With different crops and different districts, by comparing the two models, the system could offer the water-production function corresponding to the crops and the districts. For example, optimal irrigation scheduling of the system shows that Jensen multiplication model is more fitting to summer maize at Xiaohe, Shanxi than Stewart addition model, and both are fitting to spring wheat at Gulang, Gansu.