Cooperation Effect Of Water And Fertilizer On Dryland Wheat Based On APSIM

Regarded the Agricultural Production Systems simulator and spring wheatmodule as the Platform and was based on the fix position conservation tillagesystem experiment in Dingxi Experimental Station of Gansu AgricultureUniversity，the parameters of model were modified necessarily and repeatedlycombined with meteorological data, crop data and soil property data. Then I usedAPSIM model to simulate the different treatment effects for the wheat yield and itsformation factors through1971-2010,I also used other methods such as multiplexregress to quantitatively analyze the effect of the wheat yield under different growthphases with the waterfall and the couple effects about the water and nitrogen.Theresults showed that：1、Crop growth can be simulated using APSIM model crop yields. Wheatyields simulated values and measured values were distributed in1:1of the solid line,and the three decisions coefficient R squared were greater than0.9705, and themean square root value of the wheat crop is118kg/hm2.2、Three different precipitation patterns for one year of wheat production orderis: wet year> normal year> dry years. In addition, to the wheat yield and theprecipitation in the total amount, and the change of precipitation and growth periodon,different stages of the wheat yield effects are: seedling stage＞jointing stage＞flag stage＞heading stage＞filling stage＞flowering stage， therefore， theprecipitation of seedling stage and jointing stage on the influence of the wheat yieldin a certain extent appear open down quadratic parabola diminishing returns change.And seedling stage and jointing stage precipitation effect were carried flag periodprecipitation effects of6.6times and3.7times. And influences within the scope ofthe precipitation in secondary stack incremental for the heading stage, the flag stage,the flowering stage and the filling stage on wheat yield change. The seedling andthe elongation stage precipitation are main limit factors of wheat yield in theresearch area.3、In the range of0～300kg/hm2nitrogen amount used in the field, the wheat yield is increasing at the beginning and then reached a stable state relatively. Whenthe nitrogen amount is rate of0~100kg/hm2, wheat production increasedrapidly.The nitrogen amount is N>150kg/hm2, increasing about N applicationrates more, wheat yield, the nitrogen amount is N=100kg/hm2,the maximum valueof the wheat yield is2061.13kg/hm2among40years.4、For three different precipitation patterns for one year, the distribution trendis consistent, in dry years, normal year, wet year, each applied the amount of Nfertilizer on wheat yield effect is: wet year> normal year> dry years. The threedifferent types of annual precipitation in drought year’s n application on yield wereappeared in some way and return diminishing effects. The curve of the n applicationrate annual water change with in a wet year is the wheat production grew rapidly atthe beginning of the nitrogen, reached a maximum yield production rate,then beganto fall, and at last leveled off.5、The contribution rates of precipitation for the yield is greater than the effectof N fertilizer. Natural precipitation under the condition of wheat production in thestudy area is characterized by the influence of growth period precipitation (X3)>leisure period precipitation (X2)> nitrogen content (X1). Sewage sludge in acollaborative single factor deviation regression equation, when the wheat yield isalong the precipitation change, a quadratic parabola was "U" type change, napplication rates and the wheat yield is a quadratic parabolic "inverted U",precipitation’s effects on wheat yield incremental change within the scope of theprecipitation in the secondary overlay. Effect of N fertilizer on wheat yield is acertain extent, the return for diminishing quadratic parabola appeared open to thebottom. Factors affect wheat yield of synergy order of X2X3> X1X3> X1X2, wheatproduction factors are synergistic effects of the most significant growth periodprecipitation and leisure period precipitation,the heritability showed little effects oncrop yield and depends on the growth period of precipitation,which also alonedoesn’t depends on precipitation, but depends on the interaction effect betweenthem.Both of them can satisfy the needs in crop production namely that only, andcan also help the production amount to reach the maximum. It can also show that precipitation is the most significant effect on wheat production in this area.