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Vegetation is a sensitive indicator suitable for testing of ecological stresses and natural anomalies of the technogenic character. First, it is determined by the prompt response of photosynthetic apparatus to changes of environmental conditions, mainly by change of green pigment (chlorophyll) content in leaves. Second, the specific kind of a reflectance spectrum of leaves is due to chlorophyll presence in them, and the area in the range of 500-80 nm is extremely sensitive to variations of its pigment content. Thirdly, there are interesting results now concerning spectral properties of leaves and crops canopies obtaining with high-resolution spectroscopy. The data are high informative in relation to content of chlorophyll and some other biochemical constituents of a cell. The high resistance to various types of noises is inherent to methods developed on the basis of such spectral data. We have developed a method for chlorophyll estimation using the 1-st derivative plots of reflectance spectral curves. The method gives good results for plant-soil systems with both for 100% and
incomplete projective covering as our simulation models show. Field measurements of chlorophyll content in closed and open canopies crops confirm the results. A hardware-software complex has been produced by us for chlorophyll determining under field conditions. It consists of spectral and computing blocks. First of them is a two-beam spectrometer of high resolution supplied by a system to visualize of measured object. The irradiance and temperature sensors are included to the spectral block as well as GPS-receiver. The following technical characteristics are inherent to the block: spectral range 500-800 nm, band-pass 1.5 nm, field of view 16x16o, scanning time 0.1-1.0 s, dynamic range of signal 1:1024 (10 bit), signal/noise ratio 400, amount of pixels in image 1240, range of estimated chlorophyll concentrations 1.5-8.0 mg/dm2, supply voltage 12 V, weight 8 kg. Computing block is intended for spectral date processing to obtain chlorophyll estimations using our algorithm. The block is supplied by our original software WINCHL, which includes spectrum and algorithm
libraries and various mathematical tools. Accumulation of reflectance spectra of various plants together with data of environmental conditions at measurements gives a good possibility to use all of them for future scientific researches and developing other important parameters of canopy status.
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