| The studies has choused five kinds of crops of wheat, maize , potato , oil sunflower , flax, under the corresponding planting way , analyzed tow year's data of crop's characteristics of water usage in different irrigating levels in Ningxia river irrigation area. It's has choused the water-saving crops and their association mode on this basis. Combine the area to investigate, the studies suggested the Planting's structure in optimization that be changed. Studies considered the equilibrium of supply and demand of the water resource, realized the coordination and uniform of three major benefits of ecology, economy and social, and set up many goals optimize models of plant's structure on this basis in Ningxia River Irrigation Area. Studies has appraised to the result of optimizing.1. Study has appraised to the result of optimizing. The test of different irrigate levels was go on at Agricultural college of Ningxia University proving ground from 2002-2004. Wheat- ensiling maize, maize , potato , oil sunflower, flax, spring wheat / maize six planting way carried on different levels to irrigate test. Through analyzed the irrigating water amount and irrigating number of times , amount of water consumed of the breeding time of the crop, output and water using efficiency , and water-saving potentiality of the mode etc. Research had found out each kind of crops and plant the optimum irrigation mode under the cropping system .1.1 Result of the test showed that irrigate level obviously influenced breeding time of spring wheat and flax, when wheat and flax irrigated too few, wheat and flax would be early-maturing. But when too much water, wheat and flax's growing process would be accelerated and water too many would cause nutrition growing too prosperous and cause crap late-maturing. Irrigating level was different, the change of area of leaf and output of is different. In middle period of crops , irrigated more heavy, leaf area and output of colony increased more heavy. But later stage,output- accumulating speed of colony obviously droped at high water irrigating level.1.2 Water consumption and its component of crop water consumption proportion in crop's apiece growing period under different irrigation conditions was different. Proportion of the soil water supply and rainfall accounting for Water consumption was degressive when irrigate quantity increased at the same time. The amount of water consumed of each one growing period crops was different under different irrigation conditions. On the whole, The growing period biggest amount of water consumed of the spring wheat was Jointing - stage of earing . The amount of water consumed coefficient was up to 34 %-to5-48. 8%, secondly ear- form a vesicle and form a vesicle- ripe stage; It is in the jointing that the maize biggest amount of water consumed, is up to 32.7%-46.5%, except that treatment that seedling stage poured water, other treatment amount of water consumed was minimum in seed - jointing stage; Potato most heavy to consume water period was form one in the period of stem tuber taking shape ,water consumption proportion more than 60% at most, secondly it is the rise period of stem tuber, The oil sunflower consuming most water in seedling stage and the flower bud consumed most water. Treatment that poured water at seedling stage and flower bud ,it's water coefficient of consumptionreached to 313%-42% , irrigation can improve oil sunflower's the amount of consuming water of middle grow period, the flower bud stage was particularly obvious; From flower bud to bloom stage of flax, water consumption was most , but consumption was less at seedling stage and durable;Tbe coefficient of consuming water of the crop was affected by sofl water storage and climate except irrigation conditions.13 Irrigating competence will have influence in various degree on the output of the crop and output value. The result of the test indicated: the proper irrigation remarkably enhanced crop's yield. At present condition , the spring wheat yield reached at highest 4186.0 kg ? hm'Svhen it irrigated 4950 m3 hm'2water.The output of ensiling maize of spring wheat- the output planting way was influenced by irrigation conditions of the spring wheat, irrigated 900 m3.hm'2 water in the ensiling maize jointing, the output of the ensiling maize is up to 51434kg Jun'2.Irrigated water quota was 3150 m3Jun"2, the output of maize only up to 13252kg.hm"2s at most Irrigated water quota was 8100 m3inn"2,The output of spring wheat / maize was highest, the output of the wheat is 4820kg.hm'2, the maize is 9938kg.hm*2. While testing, the output of the potato irritating one time in stem tuber initial stage the was highest, reached 52445kgJnn'2, the output was lowest not pouring water and irritating four times. The output of the oil sunflower is the highest while irritating one water, irrigating amount for 1050 m3.hm"2, reach 4186kg.hm-2, the output of irritating four water is lowest. The output of the flax while irritate two water is the highest, up to 2540, kg.hm"21.4 Change tendency of output value of Every crop under different irrigation conditions was identical with field, but there is a greater difference among output value between the crops. Result of the test indicate, the output value of the spring wheat - ensiling maize, potatoes, spring wheat, the maize is relatively high. Sequences output value from high to low were the spring wheat- the ensiling maize potato, spring wheat / maize, oil sunflower, flax.1.5 This text had carried on parabolas and fitted to the irrigation quota and output of every crop through the result that was tested. I solved irrigation quota and yield when being most high output Through marginal output and marginal output value, analyzed and predicted the parameter of quota of irrigation under water-saving irrigation system of every crop. The upper limit of irrigating the quota of economy of every crop respectively is spring wheat 3423 m3.hm'2, maize 3067 m3.hm'2 , potato 2093 m3.hm'2, oil sunflower 1091 m3Jun*2, flax 2264 m3.hm'2.1.6 The quota Irrigation of every crop increased, irrigation water WUE to increase at the same time that proved the output was very strong to the dependence of irrigation. Under the different irrigation level of every crop, BEUE that only irrigated one water was the highest, IEUE of potato among them was most high, higher by 30% than other crop's most high IEUE. The increase of quantity with pouring water, IEUE of every crop dropped progressively. When the output of every crop reached highest, IEUE of the potato was the highest, respective higher by 59% and 55% than the spring wheat and maize, respective higher by 38%, 44% than oil sunflower and flax.2. Seted up plant structure programming model in Ningxia River irrigation area through data of test and data of investigation, used DPS software to carrying on linear optimization. In the planting structure in the following 15 years was optimized, if irrigating the water amount limiting under 2^00,000,000m3every year, the cultivated area of the rice will keeps in 6.70,000hm2, the cultivated area of spring wheat-the maize by 3.5,000 hm2in 2010, will rise to 37,000hm2 in 2020. The area of the spring wheat / maize drops progressively, by 53,700 hm2 in 2010, drop to 22,300 hm2 of 2020 years, the area of the industrial crops will be by 84,400hm2 in 2010 up to 85,OOOhm2 in 2O2O.The gross output value of 2010 will reach 6,804,180,000 yuan, will reach 8,587,990,000 yuan by 2020, net profit of tax reduction will rise year by year too, it will rise to 4,676,460,000 yuan by 2020. Always only irrigate the water amount minimum in between 2,233,000,000-2329,000,000 m3 in the all field every year. If irrigating the water amount limiting under 2,500,000,000m3 every year, From 2010 to 2020, the cultivated area of the maize only will keep in about 140,000hm2, the area of the industrial crops will rise from 3,4300 to 6,4500 from 2010 to 2020. The cultivated area of other crops will keep the level under 2,500,000,000m3 amount of water irrigated. The result appraised showed that this result of optimizing can meet the demand for grain, fodder, vegetables melon of regional economic development on terms .while the irrigating water yield is restricted, can get higher economic and social benefit at the same time.
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