Hyperspectral reflectance data processing through cluster and principal component analysis for estimating irrigation and yield related indicators

Eyüp Selim Köksal

Agricultural Water Management, 2011, vol. 98, issue 8, 1317-1328

Abstract: Management of agricultural practices such as irrigation by using remotely sensed data requires background data obtained from field experiments carried out under controlled conditions. In this study, spectral and agronomic data from field trials consisting of six different irrigation treatments were used to derive new spectral indicators for estimating growth level and water use status of dwarf green beans. Spectral reflectance (Ref) values were smoothed and first-order derivative spectra ([rho]) were calculated. Linear regression and multivariate analysis (cluster and principal component analysis) were done between agronomic indicators and both the smoothed spectral reflectance (R) and [rho] of each individual wavelength between 650 and 1100Â nm. Based on those calculations, the most appropriate wavelengths were selected for each agronomic indicator and new combinations were calculated by using rationing, differencing, normalized differencing and multiple regression. The ratio between [rho] measured at 950 or 960Â nm and 1020Â nm wavelengths provided estimates in an error band of 2.47Â bar for Leaf Water Potential (LWP) and 3.18% for Leaf Water Content (LWC). An equation based on [rho]740 and [rho]980 was developed to estimate Leaf Relative Water Content (LRWC). In the same manner, the [rho] at 820 and 970Â nm provided a good estimate of crop water use and the [rho] values at 770 and 960Â nm were critical for the calculation of Leaf Area Index (LAI) and dry biomass. It was also determined that the ratio of R930 to R670 can be applied to yield estimation.

Keywords: Spectral; reflectance; First-order; derivative; spectra; Wavelength; combination; Water; stress; Yield; Multivariate; analysis (search for similar items in EconPapers)
Date: 2011
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Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:98:y:2011:i:8:p:1317-1328

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