Study Of Water-demand Regulations And Water Stress Of Rice In Cold Regions

Rice Areas of northern China in the arid and semi-arid regions show the shortage of waterresources. Therefore, developing water-saving irrigation of rice is very significant to improve theefficiency of Chinese agricultural water use and ensure the food production. Besides, it is importantto relieve the contradiction between supply and demand of water resources. According to manyyears’ meteorological data, the article is mainly to study the influence of meteorological factors onwater requirement of rice and the laws of water requirement of rice in different hydrological modelyears. In the light of the field experiment made in Test Center of Heilongjiang province RiceIrrigation in2011, the characteristics of the water requirement, growth and development, cropyields and the comprehensive effects of rice under different water stress are researched. Moreover,the laws of rice water requirement in the cold regions and the effects produced by water stress areanalyzed systematically.Applying the regression analysis, relationship model between water demand of Rice andmeteorological factors in Qing’an irrigation district is established. In quantitative analysis, thetemperature, relative humidity, wind speed and sunshine hours project influence on Riceevapotranspiration. The function model for this region and its calculation parameters aredetermined by comparing and analyzing every function model.By means of the experiment, the rice water demand mainly focuses on the tillering stage,jointing-booting stage and flowering stage. The strength of rice water demand is smaller in theearly stages of the fertility, peaks in the jointing-booting stage among the whole growth period andthen shows a gradually downward trend. Crop coefficient of rice is different on various growthstages: crop coefficient in the jointing-booting and flowering period is larger, followed by themilking stage and tillering stage, smaller on the regreening and yellow ripening stage.The results are as follows: the influence exercised by various degrees of drought-hit on ricewater demand is different. Moderate drought of rice on the tillering stage greatly impacts on thewhole rice water demand, followed by drought and light. Rice water demand shows “rebound”phenomena after the end of the single-stage drought-hit processing; after a certain period of waterstress time，rice water demand is even higher than the normal irrigation.The effects produced by water stress on the plant height impenetrate the entire growth period.The greater the degree of water stress, the greater the impact on the growth of plants. The impact ofwater stress on rice tillering is larger, even higher in plant height, seed setting rate, grain weight andother indicators than those of normal irrigation. Moderate water deficit will help to tiller, On the other hand, excessive deficit will restrain the tillering of rice plants and decrease the number oftillers, which will affect the effective panicles and eventually result in a decrease in production. Byanalyzing rice yield and the constituent elements in different water treatments, it is clear thatmoderate drought can improve soil aeration, play the roll of promotion and control and makedeveloped plants roots, strong stems, reasonable population structure, that the appropriate use ofwater and fertilizer will be beneficial to produce high yield. The influences exercised by watertreatments on water use efficiency in rice are different. The moderate moisture regulation favorshigher water use efficiency.Utilizing Fuzz Comprehensive Evaluation (FCE) which is based on analytic hierarchy process(AHP), and analyzing the comprehensive influence of rice in different water treatments, theconclusion is drawn: Long Qing-dao I’s optimal water treatment is considered to be light drought,soil water content is90%saturated water capacity; Long Dun104’s optimal water treatment is dryand saturated water capacity is80%.