Hyperspectral Estimation Of Winter Wheat Yield And Grain Protein

The production of grain quality and quantity is an important guarantee for the long-term stability of the country.Timely acquisition of yield and quality data of grain crops,adjustment of field management and guidance the normal work of agricultural work,can achieve high in both quality and production of grain.Therefore,it can guide the scientific fertilization for the real-time estimation of the yield and quality of winter wheat and can have a certain practical significance to improve the yield and quality of winter wheat.Real-time estimation of winter wheat yield and protein content through the analysis of different growth stages of winter wheat canopy spectra,using successive projection algorithm(SPA)is extracted from different stages of agronomic parameters(LAI,CHL,AGDB),the characteristic bands of yield and grain protein content,and by "spectral parameters-yield and quality of ","spectral parameters-agronomic parameters-yield and quality "and" the vegetation index-yield and quality "three kinds of technologies.The results show that:1.The canopy spectra of the same growth period showed that the canopy spectra of winter wheat were significantly different under different fertilization conditions.With the increase of nitrogen application,the spectral reflectance of the canopy increased as a whole and reached the maximum at the N2 level,and then began to decline.The growth of winter wheat could be affected by different from nitrogen and phosphorus application rates.The highest spectral reflectance was observed,when the basal ratio was 7:3.The more phosphorus content,the higher the reflectivity.The spectral reflectance of the canopy of different growth period was also significantly different,specially the highest spectral reflectance up to about 0.5 in the jointing stage.2.The three technical routes of "spectrum-yield and quality","spectral-agronomy parameter-yield and quality" and "vegetation index-yield and quality" can achieve the estimation of the yield and quality of winter wheat.By the "spectral-agricultural parameters-yield and quality" model,the accuracy and universality of model are higher.In terms of agronomy parameter selection,LAI is suitable as intermediate variable for yield estimation.The best time of estimation is the flowering period,and the calibration set R2 and RMSE of estimation model are 0.81 and 1253 respectively,and R2 and RMSE of validation set are 0.76 and 1234 respectively.The aboveground dry matter is suitable as the intermediate variable of grain protein estimation model of winter wheat.The best time of estimation is the flowering period,and the calibration set R2 and RMSE of the estimation model are 0.80 and 1.43,respectively,and the validation set R2 and RMSE are 0.78 and 1.52 respectively.3.The second is the effect of the "spectrum-yield and quality" technical route estimation on the winter wheat yield and quality.The results of model estimation at different growth stages are also different.The best period of estimation of winter wheat yield is the flowering period,and the calibration model of the estimation model The R2 and RMSE are 0.79 and 986 respectively,the validation set R2 and RMSE are 0.77 and 1026 respectively;the best period of estimation of winter wheat grain protein content is the flowering period,and the calibration set R2 and RMSE are 0.78 and 1.46 respectively,and the validation set R2 and RMSE are 0.76 and 1.52 respectively.4.The technical route of "vegetation index-yield and quality" is less effective in estimating the yield and quality of winter wheat,mainly because of the "spectral saturation" phenomenon of the vegetation index,and the incomplete information extraction of the canopy spectrum.The better the growth of winter wheat,the more serious the saturation phenomenon,the R2 and RMSE that lead to the model are less than the other two technical routes.In this study the vegetation index and the yield and protein content of winter wheat showed a significant correlation at jointing,booting,flowering early filling and late filling stage(P<0.01),and provides a certain basis for the estimation of vegetation index of winter wheat yield and quality.So,in the follow-up study,the selection of vegetation index and the amount of vegetation index need to be the further studied.