Research On Spring Wheat Yield Forecasting Based On WOFOST Model

Wheat is one of the most important food crops in the world.It has the characteristics of wide distribution,large planting area and high harvest yield.In recent years,food security issues caused by the reduction of arable land and the deterioration of the ecological environment have become a focus of the country and society.The accurate,timely,and quantitative use of crop growth models to predict the output of food will help the country formulate relevant policies and achieve Rural revitalization and increasing farmers'income play a pivotal role.Although the crop growth model can describe the dynamic process of crop growth well,it is difficult to obtain the parameters of the model due to factors such as different regions,crop varieties,and the level of human management in the field,which makes the simulation accuracy of the crop model exist larger error.This paper takes Ningxia as the research area.Because the rainfall in Ningxia is more in the south and less in the north,and the difference is obvious,we consider using the WOFOST model to simulate the growth of crops under potential conditions and water constraints,so as to calculate the yield under the two production conditions.The forecast.Select the spring wheat data from three representative experimental sites in Yongning,Tongxin,and Jingyuan in Ningxia to simulate the growth and development of spring wheat from 2011 to 2015,Using the?Extended Fourier Amplitude Sensitivity Test EFAST method?and parameter optimization?Parameter Estimation,PEST method?to analyze and optimize the sensitivity of the parameters,and compare the measured values with the simulated values to evaluate the WOFOST model Simulation accuracy in Ningxia.The specific research results are as follows:?1?Under potential production conditions,whether it is based on Total Above Ground Production?TAGP?production index or Total Dry Weight of Stored Organs?TWSO?production index,when the temperature is 0?Light-Use Effic.Sing Leaf?EFFTB₀?,Temperature Sum from Emergence to Anthesis?TSUM1?,Life Span of Leaves Growing at35°C?Light-Use Effic.Sing Leaf,EFFTB₀?35 Celsius,SPAN),Efficiency of Conversion into Storage Org?CVO?and other four parameters show strong sensitivity.Under water restriction conditions,whether based on TAGP yield indicators or TWSO yield indicators,the accumulated temperature from emergence to flowering?TSUM1?,the correction factor for evapotranspiration rate?CFET?,and the specific leaf area when the growth period is 0?Specific Leaf Area,SLATB₀?,storage organ assimilation conversion efficiency?CVO?,and leaf assimilation conversion efficiency?Efficiency of Conversion into Leaves,CVL?all showed strong sensitivity.?2?Using the comparison between the measured output and the simulated output from2011 to 2015,it is obtained:Under potential production conditions,the error value of TAGP is between-403kg/hm²³75kg/hm²;the error value of TWSO is between-178kg/hm²²83kg/hm²;Under the condition of water restriction,the error value of TAGP is between-538kg/hm²⁵09kg/hm²,and the error value of TWSO is between-269kg/hm²³77kg/hm².For the number of days in the developmental period:the error between the measured value and the simulated value is small.Under potential production conditions,the best simulation result appears at the emergence stage,and the error is mostly concentrated in 0²d,and the error between the flowering and mature periods is within 0⁵d Internal fluctuation;under the condition of limited water,the simulation results of the emergence period are the best,with an error of 0²d,the simulation error of the flowering period is 3⁹d,and the simulation error of the mature period is 2⁶d.Combining the comparison between the above measured values and simulation values,it can be considered that the model has a better simulation effect on wheat yield and developmental days,and the error is within a reasonable range.?3?The accuracy of the WOFOST model based on the TWSO index under the potential production conditions is:Average Relative Error?AE?is between-133.8kg/hm²¹69.8kg/hm²,and the root mean square error?Root Mean Square Error,RMSE?is between264kg/hm²⁶94kg/hm²,and the consistency index?Consistency Index,d?is between0.922⁰.975;the accuracy analysis of WOFOST model based on TWSO under water-limited production conditions is:AE is between-161kg/hm²¹57.2kg/hm²,RMSE is between103kg/hm²⁶39kg/hm²,and d is between 0.939⁰.978,all within a reasonable range Inside.This paper chooses WOFOST model to predict the yield of spring wheat in Ningxia,and uses EFAST method combined with PEST method to analyze and optimize the parameters.The experimental results show that the optimized parameters can significantly improve the simulation accuracy of WOFOST model.