Study On Estimation Model Between Rapeseed's Canopy Spectral Parameters And Leaf Area Index

The object of this study was the high oleic acid rape.The purpose of this study was to explore the spectral characteristics and sensitive band characteristics of the canopy of high oleic rape buds under different cultivation factors,and to estimate the leaf area index LAI by data processing,data analysis and data modeling,and the application of spectral technology to the field production of Rapeseed by spectral technology.Practice provides a theoretical basis and technical support for the information acquisition,nutrition diagnosis,high-yield cultivation and production management of rape field.The ASD FieldSpec 3Hi-Res spectrometer was used to obtain the relative reflectance of canopy spectral reflectance at the three key time points of Brassica rapeseed bud bolting period,namely,first bud day,buds peak day and first flower day.The characteristic spectral parameters of the corresponding date rape were calculated by the first derivative method,and the LAI-2200 C leaf area meter was used to measure the canopy leaf surface synchronously.The product index is LAI.Using the advanced technology computing language interactive environment Matlab and the statistical analysis software SPSS,the correlation analysis of the spectral parameters of rape characteristics under different fertilizer conditions and different fertilizer types and the correlation analysis with the leaf area index LAI value were analyzed by statistical analysis and mathematical modeling,and the red edge area SDr and red yellow edge vibration were obtained through the significance test.The characteristic spectral parameters such as amplitude difference DDr.y and LAI value linearly related to a significant level.The linear model and polynomial model of the spectral parameters and LAI values of the initial bud,bud spike and first flower canopy of rapeseed were established,so as to construct a comprehensive and refined inversion model for the bud period of the canopy leaf area index information with characteristic spectral parameters as the independent variable,which was wide area,nondestructive and efficient for the use of light spectral remote sensing technology in rape production.Monitoring and measuring the growth status of rapeseed provide important technical support.The main work and results of this study are as follows:1.Characteristics of spectral parameters of early bud,buds and first flowers of rape canopy:(1)"Shuangfeng phenomenon" began to appear in the red edge of the rapeseed at 680nm-760 nm,and the red edge amplitude,red edge area,blue edge amplitude,blue edge surface of the early bud rapeseed during the treatment of combined Y6(organic manure +1 package / block +3 0000 plant / mu)cultivation factors The product is at the maximum value,indicating that the combination of the cultivation factor is related to the red edge characteristics and the blue edge characteristics,especially with the red edge characteristics of the spectrum.The absolute value of the yellow edge and the yellow edge area were relative to the maximum when the combination of F6(+32.5 kg / mu +30000plant / mu)was treated in the early bud rapeseed,indicating that the combination of the cultivation factor was associated with the characteristics of the yellow edge of the spectrum.Therefore,it is of good application value to study the characteristic spectral parameters of the above treatment combinations during the initial buds of rape.(2)Rape bud bolting peak can be identified with the special red edge position of 724 nm to guide the control of the development of rape growth.At the same time,it may be identified with the special yellow edge position of 568 nm with the red edge 724 nm,and more accurate guidance for the development of rape growth and development.The red edge parameters,yellow edge parameters and blue edge parameters of Brassica napus during the treatment of combination Y5(organic manure +1 package / block +2 0000 plant / mu)were at relative maximum.Therefore,it is of great application value to study the characteristic spectral parameters of the above treatment combinations at the peak of rapeseed bloom.(3)the red edge parameters,yellow edge parameters and blue edge parameters in the treatment of combination F8(compound fertilizer +50 kg / mu +2 0000 plant / mu)were at relative maximum.Therefore,it is of good application value to study the characteristic spectral parameters of the above treatment combinations in the early flowering stage of rape.The phenomena reflected from the maximum values mentioned above indicate that using the characteristic spectral parameters derived from yellow and blue light on the basis of the inverse of the red light band,a more accurate mathematical model can be obtained in theory,which can be used for a more fine study to find the direction of the better inversion of the self variable.2.Using the characteristic spectral parameters as a single variable,the LAI value of Brassica buds day,buds peak day and first flower day was used as the dependent variable.By linear regression,robust analysis model,polynomial regression,random forest and support vector regression modeling method,the spectral parameters of rapeseed early bud day,buds peak day and first flower day were constructed.The inversion models are compared with the LAI values,and the relative precision of these mathematical models is compared.According to the analysis results,it is found that the fitting effect of random forest RF is the best.In view of the inversion analysis of rape at different time points,the results show that the yellow edge area of rapeseed is SDy,the amplitude difference of red and blue edge DDr.b and the red blue edge area DSDr.b,the red edge area SDr and the red yellow edge area DSDr.y of the Brassica napus at the peak of Brassica napus at the peak of Brassica rapeseed are better than those of the red and yellow edge area,respectively.The three time points are taken into consideration.It is better to predict LAI with the red edge area SDr and the red yellow edge amplitude difference DDr.y.3.A linear and polynomial model was established for the spectral parameters and LAI values of the first bud,the bud peak and the first flowering canopy of Brassica napus.In the linear model,the fitting degree of model LAI = 393.26 DDr.y-0.6385 is the best,and the model LAI=-44536 DDr.y2+1373.8DDr.y-5.9591 fitting results in the polynomial model have passed the significant test,and can be applied to estimate the LAI value of the leaf area index.