SOIL-AGRO-ECOLOGICAL ASSESSMENT OF THE ARABLE LAND OF THE VALDAI UPLAND BASED ON THE GENERAL SURVEY

A methodical approach to the digital mapping of the arable lands area depending on their soil-agroecological and positional conditions is proposed. The approach was tested on a model plot located on the Valdai Upland with an area of 160 thousand ha. Small-scale agricultural development of the poorly dissected moraine plains is limited by the wide distribution of overmoistened soils. Using the traditional discriminant analysis, a measure of the topographically determined duration of soil overmoistening was calculated based on a comparison of the morphological diagnostics of water regime and topography runoff properties according to the grid elements of 30 × 30 m. The drainability range was determined for the arable lands of XVIII century, reconstructed according to the materials of the General Survey. This allowed us to determine the potential area of the arable lands for this period. The area of arable lands, which is characterized by favorable conditions of transport accessibility and soil drainability, was 12 %. At the same time, reconstructed area contained 5 %. In the subsistence economy of the XVIII century more than a half of the potential arable lands of the model region turned out to be undeveloped.