Use of an Integrated Approach for Assessing Soil Redistribution in the River Vorobzha Basin

摘要

Significant climate and crop rotation changes have taken place over the last few decades in the Central Chernozem zone of European i Russia. These have considerably influenced sediment redistribution rates within agricultural catchments. Quantitativeassessments of soil losses from cultivated lands and sediment redistribution intensity have been made using an integrated approach for typical catchments of Central Russia located near the city of Kursk in the River Vorobzha basin. Combined application of the caesium-137 (~(137)Cs) technique, erosion models, the soil morphological method and large-scale geomorphic mapping with detailed evaluation of the area of each typical morphological unit indicated that soil erosion rates on arable hill slopes decreased by about 1.5 times during the last 25 years (yr) compared with rates during the previous quarter century. Sediment delivery from cultivated fields into the River Vorobzha valley also decreased by up to three-fold over the same timeframes. The main reason for these changes was the considerably reduced surface runoff during the spring snowmelt period. In addition, the approach employed made it possible to quantify the effectiveness of soil conservation measures (SCMs) introduced within the small experimental sub-catchments occupying part of the study area. Application of SCMs reduced soil losses from cultivated fields by 2.5 times. Most of the eroded sediment and sediment-associated ~(137)Cs has been rede-posited within the cultivated fields and adjacent dry valley bottoms. It can be concluded that taking an integrated approach is the most appropriate strategyfor assessing soil degradation and determining both localized and off-site soil and nutrient sinks.