Study On Application Of Water-saving And High-yield Irrigation Control Technology For Rice In Yinchuan Irrigated Area

Based on introduction of production of rice, the present situation of water-saving irrigation technology, the conditions of rice growth and the irrigation control technology of China, this article is aimed at the practical production of Yinchuan irrigated area. The water-saving and high-yield irrigation control technology experiment, irrigation control technology experiment on alkaline soil, rice planting density experiment under irrigation control technology, the methods of nitrogen fertilizing and amount of nitrogen fertilizer experiment were carried out during 2002 to 2003. With the comprehensive analysis of experiment results, the models and guidelines of irrigation, water-saving effect, and the distinguished method of irrigating date and amount under the natural resources and rice growth technology of the Yinchuan irrigation region were discussed. The method of rice irrigation in alkaline soil and the law of the soil water and salt dynamic, the best rice transplanting density, method and amount of nitrogen fertilizer under irrigation control technology were also analyzed. The results of the study have laid the theory foundation for rice production in Yinchuan irrigated area. The progresses of the study are as follows:1. The water control irrigation technology can be used widely in Yinchuan area, and can realize rice yield increase based on the high and sustainable rice output. The average harvest yield and theoretic yield can reach 9930.0 kg/ha and 10987.5 kg/ha respectively. The yield increase ratio compared to traditional irrigation technology is 5.3%, 8.3% respectively. It can save water greatly in the case of high yield. During the rice growth period, the average amount of irrigating water is 11875.5 m~3/ha. It can save irrigation water more than 33.7% compared with traditional irrigation technology; the times of irrigation can reduce down 12.2 times and the irrigating quota can reduce to 6037.5 m~3/ha during rice growth period. As calculation of theoretical yield and practical harvest yield, the water use efficiency increase 56.6%, 55.3% respectively, the irrigating water use efficiency increase 66.0%, 60.8% respectively.2. The method of water controlling irrigation technology and the method of "water controlling irrigation technology + intermittent leaching" can save water more 71.4%, 64.2% respectively compared to traditional irrigation technology. Theeffect of two water-saving irrigation technology is obvious and can improve the yield of rice, the water use efficiency of rice is 1.55 kg/m3,1.18 kg/ m3 respectively. The irrigating water use efficiency is 1.72 kg/m3,1.29 kg/ m3 respectively.3. During different growth stages of rice, the controlling irrigation can restrain the salt accumulation in soil. So irrigation control technology can be used in alkaline soil. The water controlling irrigation model is fit for the alkaline soil which salt amount in soil is less than 0.3% at the transplanting date. But the "water controlling irrigation technology + intermittent leaching" model is suit for the alkaline soil which salt amount in soil is more than 0.3% at rice transplanting date.4. Between the treatment of different densities of transplantation, transplanting standard is 30 cmX13 an, 3 plants per cave, that is to say ,the densities of transplantation is 76.5 thousand plants per ha, that is the best density when use irrigation control technology.5. The deep fertilizing in whole soil tillage layer is the best when use irrigation control technology, its yield increase more 5.5% than the surface fertilizing. The rice yield formation and relative factors of deep fertilizing in whole soil tillage layer is good for enhancement of rice output.6. With amount increase of nitrogen application, the highest total number of rice stem increase and its time occur early. The tillering number per plant increases with the promotion of nitrogen amount and the spike formation ratio of tiller per plant of the highest nitrogen apply treatment is the lowest one. With amount of nitrogen fertilizer in 150~225 kg/ha, the tillering number increase steadily. The rice population and single plant keep a good relationship. The highest total number of stem and harvesting spike are suitable. With the promotion of nitrogen fertilizer, the heading stage will delay and the plant is easy to fall down when too much nitrogen applied. The suitable amount of pure nitrogen is less than 225 kg/ha.7. The rice yield with different amount of pure nitrogen fertilizer show that the yield of treatment of 225 kg pure nitrogen per ha is the highest one. Referring to the yield formation factors, with amount of nitrogen increase, the harvesting spike number increase accordingly, and the length of spike get longer, the number of first branches and the second branches of spike, and grain number per spike increase. But when the nitrogen amount reach more than 225 kg/ha, the ratio of sterile grain of spike increase, grain number per spike, the filling grain number of spike and 1000-grain weight will get down. From the effect of marginal yield point of view, the rice yield increase with nitrogen amount increase in the range of 0~225 kg/ha. Inthe rang of 75 ~ 150 kg/ha, marginal yield increase greatly, but when the amount of nitrogen is more than 225 kg/ha , the yield of rice decrease. Considering the economic factors, the optimum amount of nitrogen is 217.35kg/ha, and the rice yield is 12505.95kg/ha.