Vegetation cover degradation is still a very common problem in many parts of Morocco;moreover, it affects straight up the amount of the annual soil loss rate. The analytical approach used in this study, respectively, ...Vegetation cover degradation is still a very common problem in many parts of Morocco;moreover, it affects straight up the amount of the annual soil loss rate. The analytical approach used in this study, respectively, includes remote sensing techniques, application of USLE (Universal Soil Loss Equation) and overlay analysis in a raster Geographic Information System (GIS) environment, employing available information on the region covering the Kalaya catchment. Thus, this procedure allowed the calculation of the NDVI (Normalized Difference Vegetation Index), the execution of two types of classification (unsupervised and supervised) for 1999 and 2010 imagery and eventually the prediction of soil erosion risk in the watershed in question. The main outcome was the production of multidate vegetation cover maps, land use maps and soil loss risk maps. The overlay of two maps allowed us to highlight the changes occurred in this area, which evidence the high anthropogenic impact on the dynamics of land use and vegetation cover. The results suggest that the outputs of this study can be used for predicting rate of soil loss, which varied from 31.68 t·ha-1·yr-1 in 1999 to 34.74 t·ha-1·yr-1 in 2010.展开更多
Soil erosion from agricultural fields is a worldwide problem,to influence water quality,soil fertility and reservoir sedimentation especially in Mediterranean countries such as Morocco.In fact,this work assesses the e...Soil erosion from agricultural fields is a worldwide problem,to influence water quality,soil fertility and reservoir sedimentation especially in Mediterranean countries such as Morocco.In fact,this work assesses the effects of Best Management Practices (BMPs) on sediments using the Soil and Water Assessment Tool (SWAT) model in the Kalaya watershed in Northem Morocco,to recommend the most appropriate practice.This study is based on the use of three most usable practices:contouring,stripcropping and terracing,by the calibrated SWAT model.The general parameters of the model have been modified to reflect the implementation of different agricultural BMPs used.Resulting sediment yield were compared with the baseline scenario,for validation.However,the effective measures to reduce sediment losses at the watershed level are organized according to their effectiveness,and these are terracing (28% reduction and the value is 15t/ha/yr) followed by strip-cropping (9% reduction and the value is 5t/ha/yr).In contrast,measurements performed by the contouring are inappropriate for the study area because they have contributed to increasing the soil erosion (more than 31% of losses and the value is 17t/ha/yr more than existing conditions).Therefore,the model illustrates that the terrace is effective for reducing sediment losses and limiting soil erosion especially on steep slopes.Thus,the results provide useful information for targeted management in order to implement the most effective agricultural BMPs in the watershed.展开更多
文摘Vegetation cover degradation is still a very common problem in many parts of Morocco;moreover, it affects straight up the amount of the annual soil loss rate. The analytical approach used in this study, respectively, includes remote sensing techniques, application of USLE (Universal Soil Loss Equation) and overlay analysis in a raster Geographic Information System (GIS) environment, employing available information on the region covering the Kalaya catchment. Thus, this procedure allowed the calculation of the NDVI (Normalized Difference Vegetation Index), the execution of two types of classification (unsupervised and supervised) for 1999 and 2010 imagery and eventually the prediction of soil erosion risk in the watershed in question. The main outcome was the production of multidate vegetation cover maps, land use maps and soil loss risk maps. The overlay of two maps allowed us to highlight the changes occurred in this area, which evidence the high anthropogenic impact on the dynamics of land use and vegetation cover. The results suggest that the outputs of this study can be used for predicting rate of soil loss, which varied from 31.68 t·ha-1·yr-1 in 1999 to 34.74 t·ha-1·yr-1 in 2010.
文摘Soil erosion from agricultural fields is a worldwide problem,to influence water quality,soil fertility and reservoir sedimentation especially in Mediterranean countries such as Morocco.In fact,this work assesses the effects of Best Management Practices (BMPs) on sediments using the Soil and Water Assessment Tool (SWAT) model in the Kalaya watershed in Northem Morocco,to recommend the most appropriate practice.This study is based on the use of three most usable practices:contouring,stripcropping and terracing,by the calibrated SWAT model.The general parameters of the model have been modified to reflect the implementation of different agricultural BMPs used.Resulting sediment yield were compared with the baseline scenario,for validation.However,the effective measures to reduce sediment losses at the watershed level are organized according to their effectiveness,and these are terracing (28% reduction and the value is 15t/ha/yr) followed by strip-cropping (9% reduction and the value is 5t/ha/yr).In contrast,measurements performed by the contouring are inappropriate for the study area because they have contributed to increasing the soil erosion (more than 31% of losses and the value is 17t/ha/yr more than existing conditions).Therefore,the model illustrates that the terrace is effective for reducing sediment losses and limiting soil erosion especially on steep slopes.Thus,the results provide useful information for targeted management in order to implement the most effective agricultural BMPs in the watershed.
