Study On The Production Function Of Summer Soybean In Huaibei Plain Water Based On Drought Test

With the development of industry and city,the proportion of agricultural irrigation water will continue to decline in Anhui.It is estimated that by the middle of twenty-first Century,the proportion of agricultural water will be reduced to about 52%.Coupled with the low utilization rate of water resources,serious waste of water resources and unreasonable water use structure,the shortage of agricultural water resources is becoming more and more serious.It is an important problem for us to improve the efficiency of agricultural water use and save the water for agriculture.In 2015 and 2016to carry out drought of summer soybean pot experiment,from two aspects of qualitative and quantitative study on the effect of water on crop growth,to reveal the development rule of different growth stages and different crop drought conditions of evaporation,The rule of yield reduction loss at different growth period of drought,to analyze the sensitivity of crops at different growth stages under different conditions of drought,the water production function of summer soybean in Huaibei plain was established,the conclusions obtained are as followed:?1?In order to research the effect of drought stress on crop growth at different growth period,control factor was different soil water at certain growth period,nine water treatments were set,including slight and serious drought stress at flower podding stage,pod filling stage,branching stage and seedling stage and no drought stress at whole growth period?CK?,then the water consumption law under drought and the effect of drought stress on yield and water use efficiency?WUE?were analyzed.The results showed that drought stress caused the reduction of soybean normal water consumption,and the proportion of reduction increased with the stress degree;the growth period of drought stress on summer soybean yield losses of different drought at seedling stage and branching stage had little effect on yield,and the flower and pod stage and pod maturity regardless of light drought or heavy drought treatments on yield loss were significantly higher than the seedling and branching stage,especially the largest flower and pod yield loss;the effects of drought stress on WUE differ at different growth stages,the influence at seedling and branching stage was less,but the WUE under serious drought stress at flower pod stage was the smallest.?2?To obtain the crop coefficient suitable for the area of Huaibei Plain in Anhui Province and to accurately estimate the amount of soybean evapotranspiration under drought stress,Genetic algorithm?GA?was used to calibrate the single crop coefficient and soil water stress coefficient,and the single crop coefficient method was applied to estimate the evapotranspiration under drought stress.The results showed that the crop coefficients obtained by GA were K_cini=0.853,K_cmid=1.418 and K_cend=0.6959;the daily evapotranspiration of summer soybean under different drought stress was estimated,the range of MAE was 0.52⁰.68mm/d,RMSE range was 0.62⁰.79mm/d,and MRE range was 16.16%²2.22%,the mean values were 0.59mm/d,0.69mm/d and 19.90%respectively,the calculation results of evapotranspiration estimation of summer soybean under drought stress based on single crop coefficient and genetic algorithm are reasonable and reliable.?3?In order to accurately estimation soybean evapotranspiration under drought stress, the applicability of random forest?RF?algorithm is discussed,according to the summer soybean potted drought test in 2016,constructed the estimation model of soybean evapotranspiration under drought stress based on random forest.The results showed that the estimated value of the RF model is consistent with the measured value,the RF estimated model MRE range in 8.49%³8.57%,RMSE range in 0.70¹.28mm,NSE range in 0.88⁰.97,there average value is 18.28%,0.98mm,0.93,compared with the BP estimation model,the MRE,RMSE and NSE of the RF estimation model were reduced by 47.91%,36.53%and 12.16%respectively.?4?In order to correctly evaluate the benefit of disaster reduction and reduce the risk of drought,it is very important to establish the water production function of summer soybean under drought stress,according to the 2015 and 2016 in Huaibei plain in summer soybean drought experiment data,establish the water production function of summer soybean based on GA-Jensen model.The results showed that the order of water shortage sensitive index of summer soybean in Huaibei plain was flower pods>drums maturity>branching period>seedling stage.The fitting results of GA-Jensen and Jensen models are good.The applicability of GA-Jensen and Jensen models in Huaibei plain is preliminarily verified,and the water production function of summer soybean in Huaibei plain is more reliable based on GA-Jensen model.