Dokuchaev P.M., Meshalkina Yu.L.
DETERMINATION OF ORGANIC CARBON CONTENT USING A PORTABLE SPECTROMETER-RADIOMETER ^{[№ 10 ' 2016]}
The real-time measurement with a given accuracy of the organic matter content in the upper (fertile) soil layer is indispensable for competent agricultural production management. Using the spectral reflectance of soils in the visible and near infrared region of the spectrum is one of the most advanced techniques for determining organic matter content. The advantages of the method are: the speed of shooting, relative cheapness, less labor input in the preparation of samples, no need for special treatment with chemical reagents, etc. The determination of reflection spectra in visible and infrared region of the spectrum was conducted on natural and anthropogenic soils of Vyatka-Kama Province of sod-podzolic soils of the southern taiga, using a portable spectrometer-radiometer. The occurrence of relationship between the organic carbon content and the spectral reflectance of the samples was revealed in the visible and infrared region of the spectrum. It was shown that the best predicting results were obtained for the organic carbon content of undisturbed humus horizons using the Karmanov coefficient (R² = 0.41). Correlations were significant for arable horizons too, but in general they were low: R² = 0.21–0.22. Vegetation Index NDVI could explain about 26 % of the variation of organic carbon content in the upper mineral soil horizon, regardless of the land use. The study showed the presence of the potential use of the recording of the upper humus horizon reflectivity using a portable spectrometer-radiometer for rapid determination of organic carbon content for the purposes of agriculture, agro-ecological and soil mapping. However, it was noted that there is a need of development, calibration and setting procedures for each specific area.