| Heilongjiang Province was the important commodity grain base, and undertaked the importantmission of national food security, which was located in the north spring maize of northeast. Thetotal water resources in Heilongjiang Province were810.33billion cubic meters, both the averageperson possession and per mu possession of water were under the national average. The scarcity ofirrigation water had been intensified by uneven distribution of the spatial and temporal of waterresource, multiple seasonal drought, uneven distribution of water resource in the growth period,unreasonable use of water and fertilizer. The deficiency of irrigation water had become the mainlimiting factor for the development of the maize planting area and improvement yield. Regulateddeficit irrigation was the new management technology of water saving irrigation from the angle ofcrop physiological, whose aim was increasing crop yield, decreasing water consumption, andraising the water use efficiency. Under regulated deficit irrigation and coupling effect of irrigationand nitrogen fertilizer of maize, the study on impact of growth and yield of maize provided atheoretical basis for the producti of highly effective water-saving agriculture on technology ofwater saving and high yield, and had the important significance for the development.On the basis of the data measured in the barrel experiment and test-pit experiment, someeffect of growth indexes, water consumption, yield, yield components of maize were studied byusing comparison method, statistics method, and the intelligent optimization algorithm, includingthe period of regulated deficit irrigation, the degree of water deficit, irrigation and nitrogenfertilizer. Analysis results and conclusions of the thesis are as follows:(1) The plant height of maize had different compensative growth after re-watering, increasedamplitude of compensative growth related with the level of irrigation, the higher the level ofirrigation the bigger degree of compensative growth. Compared with the normal irrigationtreatment of the whole growth stage, increment of plant height of medium water deficit treatmentduring seedling stage was increased by27%between jointing stage and filling stage afterre-watering at jointing stage. Compared with the normal irrigation treatment of the whole growthstage, increment of plant height of medium water deficit treatment during seedling stage andjointing stage was increased by8%between anthesis stage and filling stage after re-watering atanthesis stage. Suitable regulated deficit irrigation could inhibit the growth of aerial part andimprove root dry weight. The average shoot dry weight of the normal irrigation treatment of the whole growth stage was increased by31%compared with each regulated deficit irrigation. The rootdry weight of medium water deficit treatment during seedling stage and medium water deficittreatment during jointing stage were respectively increased by7.7%and10.6compared with thenormal irrigation treatment of the whole growth stage. The root-shoot ratio of medium water deficittreatment during seedling stage, medium water deficit treatment jointing stage, and medium waterdeficit treatment anthesis stage were respectively increased by20%,52%, and21%compared withthe normal irrigation treatment of the whole growth stage. Continuous growth period of mediumwater deficit would greatly decrease root dry weight, suitable water deficit would increase theroot-shoot ratio and control the distribution ratio between root and shoot.Under low nitrogen condition, water deficit on the effect of the plant height of seedling stagewas less than that of jointing stage and much less than that of anthesis stage. Under mediumnitrogen condition, water deficit on the effect of the plant height of jointing stage was more thanthat of anthesis stage, the compensative growth of the plant height was increased by the treatmentcombined with high nitrogen, which was serious water deficit of jointing stage after re-watering atanthesis stage. Under medium nitrogen condition, there was unfavorable effect for the stemdiameter by serious water deficit of seedling stage and jointing stage, there was not effect for thestem diameter by medium or light water deficit of anthesis stage. The degree of water deficit wasdetermined by nitrogen rate. The stem diameter was decreased by high water and high nitrogen atseedling stage. In order to avoid effect of the stem diameter, the more serious water deficit, themore nitrogen rate was. The stem diameter was not obviously influenced by nitrogen rate and waterdeficit at anthesis stage.(2) There was different variation of maize water consumption at each growth stage caused bywater deficit. Evapotranspiration was reduced by water deficit at growth stage, which had obviousincreasing compared with normal irrigation after re-watering.Compared the normal irrigation, theevapotranspiration of medium water deficit treatment during seedling stage, medium water deficittreatment during jointing stage, medium water deficit treatment during anthesis stage wererespectively reduced by38%,31%, and30%. The total evapotranspiration was reduced by4%～8%compared the normal irrigation at single growth period during seedling stage, jointing stage,anthesis stage. The total evapotranspiration was reduced by11%～15%compared the normalirrigation at tow growth period during seedling stage, jointing stage, anthesis stage.Evapotranspiration of the treatment with high nitrogen rate and medium water deficit at seedlingstage was more than the treatment with normal irrigation, a similar result was proved for anothertreatment with low nitrogen rate and serious water deficit at seedling stage. The treatment withmedium water deficit at seedling stage had the maximum water use efficiency, which was increasedby12%compared with the normal irrigation treatment of the whole growth stage. The water useefficiency of medium water deficit treatment during seedling stage were respectively increased by6.8%,8.3%, compared with medium water deficit treatment jointing stage and medium waterdeficit treatment anthesis stage. Evapotranspiration of the plant was reduced by the proper regulated deficit irrigation, meanwhile, the purpose of regulated deficit irrigation was proved, asincreasing water use efficiency, saving water, and improving yield.(3) The value of100-seed weight of maize would be increased with medium water deficit atseedling stage or medium water deficit treatment jointing stage. Medium water deficit at anthesisstage would increase the length of barren ear tip affect the yield. For the treatment with mediumnitrogen rate and light water deficit or the treatment with high nitrogen rate and serious waterdeficit at jointing stage, which the length of maize ear could be increased. Water deficit at anthesisstage affected yield mostly, followed by that at jointing stage, and the least at seedling stage.Maintaining the level of water deficit50%～60%of the field capacity at the seedling stage andwater deficit70%～90%of the field capacity at the other stages was the best deficit irrigationscheme of the economic yield, which was16483kg/hm2. Compared with the normal irrigationtreatment, the best irrigation scheme of the economic yield was increased by6.4%and the wateruse efficiency was increased by10.8%. The best deficit irrigation scheme of water saving was thatmaintaining the level of water deficit percentage of the field capacity was respectively50%~60%、65%~75%and65%~75%at seedling stage, jointing stage and heading stage of maize, which was13503kg/hm2. Compared with the normal irrigation treatment, the best deficit irrigation scheme ofwater saving was increased by8%and the water use efficiency was increased by12.6%. When thetarget yield was above13500kg/hm2and confidence interval was95%, the best deficit irrigation ofhigh yield and high efficiency water saving was that maintaining the threshold of water deficit48%～66%of the field capacity at the seedling stage of maize, the threshold of water deficit72%～84%of the field capacity at the jointing stage of maize, the threshold of water deficit66%～81%of the field capacity at the anthesis stage of maize, and nitrogen rate with160kg/hm2.(4) The traditional least-squares regression and the partial least-square regression were appliedto set up the yield model of the maize regulated deficit irrigation, which dealed with seriousmulticollinearity and a small with numerous predictor variables, eliminated the bad impact ofserious multicollinearity among factors, explained the dependent variables very well. Aftercalculation and analysis, both absolute error and relative error of the partial least-square regressionwas batter than the traditional least-squares regression. The model of the partial least-squareregression solved the problem of the multi-correlation with good stability, which explained thedegree and direction of each independent variable to the effect of yield, its simulation resultsequated with actual situation of the experiment.Due to the incompatibility of irrigation results for single evaluation index and difficulty inevaluating the comprehensive benefit objectively during the process of optimization choice ofirrigation schemes, the project pursuit model based on improved double chains quantum geneticalgorithm was proposed and applied to the comprehensive evaluation of regulated deficit irrigation.The model not only evaluated the contribution rate of each evaluation index to the target yield, butalso determined the optimum technical scheme of regulated deficit irrigation. The results showedthat the evaluation result was affected mostly by the yield of maize, and followed the order of height, root dry weight,100-grain weight, barren ear tip, water use efficiency. maintaining thelevel of water deficit50%～60%of the field capacity at the seedling stage of maize was the bestirrigation scheme. Compared with the normal irrigation treatment, the yield was increased by6.4%and the water use efficiency was increased by10.8%. The evaluation result of the model wasconsistent to real yield and computation, both the global search capability and optimizationefficiency of the improved projection pursuit model were significantly improved, which hadimportant guiding significance. |
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