Soil washout by thawed snow on arable lands of northern Krasnoyarsk forest-steppe

Results of the 2009-2011 researches of washout(accumulation) of soil on arable lands of the northern part of Krasnoyarsk forest-steppe at an experimental site typical for the giventerritory (natural boundary of the Dolgiy Log gully) are considered. The agricultural background of the arable lands of the experimentalsite for the years of research was stubble, winter crops, complete fallow, and layland. The mechanical structure of the soil cover ismainly medium loam and clay loam. Large fractions of sand are accumulated in the bottoms of flow erosions and holes during thedistribution of streams of thawed snow oversaturated with diluvium. The depth of freezing of soil in the considered years was 1.2-1.5m,the depth of thawing by the time of measurement of washout sizes averaged to 15-17 cm. The site of the Dolgiy Log is surrounded byforest, which increases accumulation of snow and influences its distribution on the arable land. On the slopes of the northern expositionthe accumulation of snow is 1.5-2 times higher than on the southern one. The maximal accumulation of snow was fixed annually in theeastern part of the northern part at the edge of the forest. The micro-relief of the arable land essentially influences the accumulation anddistribution of snow. Its character predetermines the formation of education of the channelized flow. The most important distinctivefeatures of the Dolgiy Log, rendering the most essential influence on soil erosion are plough works mainly along the slopes; prevalenceof rather low slopes with significant length - from 500 to 1300m; bordering with forest, which increases snow accumulation; slopes andagricultural background condition influencing the speed of water-currents and turbidity waters. The results of the observations show thatthe maximal values of erosion were observed in 2009, minimal - in 2010. In 2011 the size of washout was average. The principal causesof the specified distinctions are connected with unequal pre-winter humidifying of soil and various stocks of water in the snow cover.Territorial generalization of the given observations by distribution of characteristics of washout on the sites we have not studied withsimilar conditions of slopes, length, exposition, location is executed.

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