Hyperspectral Monitoring Of Tartary Buckwheat Yield Under Selenium Application

Crop yield estimation is of great significance to China's crop policy revision.The traditional estimation method is time-consuming and high-cost,while hyperspectral remote sensing technology can make up for the traditional estimation shortcomings.Tartary buckwheat is not only rich in protein,minerals and other nutrients,but also has medicinal value.In this experiment,Tartary buckwheat "Heifeng No.1" was used as material,different concentrations of sodium selenite(Na2Se O3)were sprayed on the leaves of the field,By measuring canopy spectra,leaf area index,chlorophyll content,quantity and production on the dry on the ground,vegetation index are analyzed,and the relationship between the main agronomic parameters and output,main agronomic parameters as link point to build the buckwheat yield monitoring model based on spectral vegetation index.The results show:1.The spectral reflectance of Tartary buckwheat canopy with different growth processes has certain differences.The spectral reflectance of Tartary buckwheat canopy with different growth processes shows a declining trend in both visible and near-infrared bands as the growth process changes.Under different selenium treatments,the spectral reflectance of Tartary buckwheat canopy in the whole growth process also showed some differences.The change trend was not obvious in the visible light band,but obvious in the near-infrared light band.With the increase of selenium application amount,the spectral reflectance of near-infrared light band showed a declining trend.2.The leaf area index,chlorophyll content and aboveground dry biomass of Tartary buckwheat showed some changes under different selenium treatments.With the increase of selenium application amount,the first increase was followed by a decrease.The changes of leaf area index,chlorophyll content and aboveground dry biomass of Tartary buckwheat increased at first and then decreased with the advance of growth process under the same application of selenium in different growth processes.Under different selenium treatments,the basic change trend of yield was consistent with agronomic parameters.3.Based on the characteristic bands of each agronomic parameter extracted by continuous projection algorithm(SPA),the vegetation index of each agronomic parameter was constructed.Throughanalysis,spectral parameters of 535 nm,758 nm and 535 nm,994 nm combination of vegetation index and the better the fit of the buckwheat leaf area index,spectrum parameters of 545 nm,736 nm and 545 nm,895 nm combination of vegetation index and buckwheat better fit of the chlorophyll content,spectral parameters of 449 nm,806 nm combination of vegetation index and the fit of the buckwheat dry biomass on the ground is better.4.According to the correlation analysis of agronomic parameters and vegetative index of different growth stages of Tartary buckwheat and corresponding agronomic parameters and yield of Tartary buckwheat,the models of vegetation index and yield of Tartary buckwheat linked by aboveground dry biomass were Y=-0.2652(-0.0014X2+0.1121X-2.0557)2+23.598(-0.0014X2+0.1121X-2.0557)-243.34,R2 was 0.7396,which had good correlation and could estimate Tartary buckwheat yield accurately.