| The paper mainly studied on reflectance spectra characteristics and the extraction of biophysical and biochemical parameters of summer maize based on the field and leaf spectral data. The main contents and conclusions of this paper are summarized as follows: (1) Spectral discrepancy was compared and analyzed synthetically among different varieties at different growth stages of summer maize.The results indicated: the spectral discrepancy surely existed among the different varieties. along with the growth, spectral discrepancy took on disciplinary chang, namely, the discrepancy gradually increased from jointing stage to tasseling stage, thereafter, the discrepancy was bigger at anthesis than that at anthesis, which happened between 420 ~ 475nm, 510 ~ 580nm and 705 ~ 1005nm. (2) Reflectance spectra characteristics were analyzed under the condition of different growing sta-ge, versatile space tool, versatile viewspace angles, different planting density, different LAI, differ-ent nitrogenous levels, different leaf water content and the growth with the grass. (3) The paper analyzed the extraction of biophysical and biochemical information using remote sening based on reflectance spectrum and derivative spectrum canopy. The results indicated: Red edge slope slowly increased, and REP moved to the long wave band side from jointing stage to tasseling stage, which was called "red transference", and then it stopped in tasseling stage after the population was stable.The change was contrary from anthesis to milking stage,which was called "blue transference".It was feasible to estimate CHL.D by using the first derivative spectrum and REP, and the properest models were index(R2=0.9487)and parabola (R2=0.9392) respectively. (4) The paper analyzed the extraction of biophysical and biochemical information using remote sening based on red edge parameter. The results indicated: ①Dλred/Dλmin was added to simulate LTN more accurately than Dλmin during the growth, Dλred before anthesis, λred at jointing stage and bell stage. The result of utilizing Dλred for estimating Chl was encouraging before anthesis, λred at bell stage and tasseling stage. It was feasible to estimate LAI with Dλred after tasseling stage or with λred and Dλmin at tasseling stage, furthermore, using Dλred/Dλmin was more reliable than the others at anthesis and silking stage. ② the FD_Max could be used to predict the leaf area index; Depth672 for the stem water content; Lwidth for the leaf total nitrogen content, water content and soluble sugar of leaf and stem, the REP for SPAD, ND672 for chlorophyll-a; Area672 for chlorophyll-b and chlorophyll-a+b; Lwidth for the ratio of chlorophyll-a and chlorophyll-b; FD_Max for carotenoid; Area672 for the ratio of carotenoid and chlorophyll-a.The regression models, based on red edge parameter, were also established. (5) The paper analyzed the extraction of biophysical and biochemical information using remote sening based on vegetation index(VI).The results indicated that VI could assess LAI accurately. Especially, R810/R560 was remarkably correlated with LAI in exponent form,which couldn't be affected by the varieties,growth durations and nitrogenous levels.The regression model as follows: LAI= 0.765e0.2637R810/R560.The model was synthetically tested with sample A and B respectively and the assessment average R2, precision and accuracy were about 0.9573**,95.63%and 98.47%with average RMSE of 0.0365 respectively. (6) The paper analyzed the extraction of biophysical and biochemical information using remote sening based on 55 typical spectral parameters.The statistical correlation coefficients between 55 typical spectral parameters and the biochemical contents or physical parameters were analyzed in all growth stages, and the remote regression models for different biochemical contents in different growth stages were built based on their sensitive spectral parameters. (7) The paper studied on the diagnosion of biophysical and biochemical information based on leaf spectrum data. The reflectance, transation... |
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