Application of UAV and spectrometric survey results to determine agrochemical parameters of zonal soils used in agriculture (East of European Russia)

Abstract

To determine the degree of degradation of agricultural lands for a key values (humus content, mobile potassium, mobile phosphorus, PH), the use of multispectral UAV materials synchronized with ground-based spectrometric imagery is proposed. Spectroradiometer HandHeld 2, soil acidity (pH) meter, satellite GLONASS-GPS receiver of geodetic class were used for field survey. Multispectral orthophoto obtained at the time of ground surveys using multispectral cameras Tetracam Micro-MCA 4 and Tetracam ADC-micro installed on board of the Supercam-S350F UAV. In parallel with the spectrometric work, samples of soils of different soil varieties and washout degree were taken, in representative sites of elementary soil areas. Laboratory studies were carried out with the selected samples, in order to determine the main agrochemical parameters: humus (%), mobile phosphorus (mg), mobile potassium (mg), pH (H₂O). The work was tested on two field sites located in the Chuvash Republic (Russia), on cultivated (arable land) forest-steppe zonal soils (leached chernozems, dark gray forest soils). As a result of mathematical data processing, statistically significant relationships were obtained between certain groups of agrochemical indicators and spectral data in different channels of UAV images for specific soil varieties. In the course of the study, relationships were found between the green, NDVI, NIR, red channels obtained using the Supercam-S350F unmanned aerial vehicle and laboratory data: humus, phosphorus, potassium and soil pH. In general, the results of the experiment prove the fundamental possibility of using multispectral UAV materials, together with ground spectrometric imagery for automated express determination of agrochemical indicators of agricultural lands.