| In order to achieve rapid monitoring of leaf relative water content of winter wheat at different growth stages, this study was based on five kinds of hyperspectral indices, which were calculated by capony hyperspectral data and infrared thermal imaging data of winter wheat.Through the analysis and screening of fitting conditions between leaf relative water content and hyperspectral index at different growth stages, leaf relative water content monitoring models based on hyperspectral indices were obtained, which were validated further in our study.Results indicated that leaf relative water content was significantly related(P<0.01) to ratio vegetation index(RVI), normalized difference vegetation index(NDVI), ratio/normalized vegetation index(R/ND), optimized soil adjusted vegetation index(OSAVI) and capony-air temperature difference(TDc-a) at different growth stages.Monitoring models based on NDVI, OSAVI, R/ND, TDc-a and TDc-a produced better estimation for leaf relative water content at jointing stage, heading stage, flowering stage, early filling period and late filling period, i.e. coefficients of determination(r) were 0.842, 0.884, 0.831, 0.864 and 0.945, respectively.For prediction models, root mean square error were respectively 0.019, 0.016, 0.027, 0.032, 0.024 and mean relative error were 2.26%, 1.80%, 3.30%, 3.81%, 3.53%, respectively.Therefore, NDVI, OSAVI, R/ND, TDc-a and TDc-a vegetation indices were more likely to be used to monitor leaf relative water content at jointing stage, heading stage, flowering stage, early filling period and late filling period, respectively.This study can provide technical support to a certain extent for water monitoring of winter wheat at different growth stages in field. |
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