Migrational Structure of the Landscape-Geochemical Arena and Soil Solid Phase Mobility

The spatial structure of solid-phase soil migration was examined for the landscape-geochemical arena located within a small first-order gully catchment on the Central Russian Upland in the broad-leaved forest zone, where plowland occupies 87 percent of the area. Rates of dispersion and accumulation of the soil solid-phase material were determined using the magnetic tracer method over the past 143 years. For comparison, data from the soil-morphological method with a 300-year assessment period and the radiocesium method with a 25-year assessment period were also considered. The migrational structure includes the following components: (a) identified areas of soil solid-phase dispersal and accumulation, numbering 15 and 16, respectively, within the studied arena, characterized by rates and volumes of material movement, genesis, and degrees of migrational conjugation; (b) connectivity parameters between dispersal and accumulation areas, highlighting the main donors and acceptors of soil material for each area; (c) modifications of soil-geochemical catenas, classified according to transport rates, volumes, and average migration distances of the solid-phase material, with identification of factors influencing these parameters; (d) spatial characterization of temporal changes in transport and accumulation rates, expressed as zones with similar types of balance shifts within the arena; (e) the overall soil solid-phase balance for the arena and its individual parts, expressed as an average annual transport of 687 tons per year and accumulation of 53% of soil material within the catchment, including 13% on arable slopes, 15% on grassed slopes, and 25% in the gully bottom.