MAPPING OF RILL EROSION OF ARABLE SOILS BASED ON UNMANNED AERIAL VEHICLES SURVEY Article Kashtanov A.N., Vernyuk Y.I., Savin I.Y., Shchepot’ev V.V., Dokukin P.A., Sharychev D.V., Li K.A. Eurasian Soil Science. Vol. 51. 2018. P. 479-484