Место издания:Department de Medi Ambient Lleida, Spain
Первая страница:114
Последняя страница:114
Аннотация:Soil erosion totals can be dominated by a few extreme events, thus monitoring, as well as erosion model simulation need to be long enough to capture these erosive events. It should be taken into consideration, that land use and climate changes is also influenced on the average erosion rates. Quantitative assessment of erosion rate trends was undertaken for the two regions of the Russian Plain (Voronezhskaya oblast’ and Tatarstan Republic), located in the different parts of the forest-steppe zone with very high proportion of croplands. Detail assessment of erosion rate for two time intervals (1963-1986 and 1986-2015) was done in one river basin and one cultivated watershed located within studied river basins in each region. Modified versions of USLE and State Hydrological Institute models were applied for calculation of soil losses for warm period of year and snow-melt respectively. Land use changes was identified by visual interpretation of multi-seasonal images Landsat 5 and Landsat 8 which was done in 1985-1986 and 2013-2015. Meteorological characteristics was collected for the period 1960-2015. Crop management coefficients was evaluated based on statistical information about area under the different crops on the regional scale for period 1960-2015. The bomb-derived and Chernobyl-derived 137Cs were used for the determination of sedimentation rates in the valley bottoms in the studied watersheds. The trend of reduction of average soil erosion rates was found for the both regions. The global warming is the main reason of decrease of soil erosion rate. Increasing of winter air temperatures led to reduction of soil freezing depth and hence to decreasing of surface runoff from cultivated slopes during snow-melt. Results of the detailed assessments of sediment redistribution rates for the two times intervals within the key watersheds were used for verification of the results of soil erosion rate calculations within the studied river basins.