Soil erosion, nutrient migration and surface water pollution in Russia

The evaluation of soil erosion-originated transport of nutrients (C, N, P, K) from arable slopes is presented in this paper. The results are based on the map "Erosion-affected land in Russia" (scale 1: 1 500 000) and agrochemical data. Annual N, P and K losses (in gross forms) are estimated to be 1.4, 1.1 and 11.8 x 10(6) t, respectively. Soluble forms of P (phosphorus) and K (potassium) are exported at the rate of 53 and 68 x 10(3) t, respectively. Average annual soil loss from arable land of Russia is about 560 x 10(6) t, including 26.3 x 10(6) t of humus. Landscape zones and, most importantly, arable land topography, are major factors controlling regional variability of nutrient losses. Conditional P concentration is directly proportional to the amount of its erosion-originated loss and is inversely related to runoff layer. The P conditional concentration (C-cP) calculations for all drainage basins of large Russian rivers have been used for to assess the ecological risk of surface water pollution. The North-Caucasian rivers appear to be the most endangered from this point of view.