Based on the distribution of hydrological stations and zoning of types ofsoil erosion, the Loess Plateau (3 10 x 10~3km^2) is divided into 292 erosion units. And taking theerosion modulus > 5000t/km^2 as a criterio...Based on the distribution of hydrological stations and zoning of types ofsoil erosion, the Loess Plateau (3 10 x 10~3km^2) is divided into 292 erosion units. And taking theerosion modulus > 5000t/km^2 as a criterion, the emphasis control area (149 x 10~3km^2) of the LoessPlateau is demarked, and is divided into 10 control regions. The controllable area and the locationof control measures are conformed. Level terraces are mainly collocated on the 3° ―15° slopes,woodland and grassland are collocated on the > 15° slopes, and the proportion of woodland tograssland is 8: 2 in the forest belt, 5: 5 in the forest steppe belt, and 2: 8 in the steppe belt.The 9000 combinations of soil-water conservation measures in different rainfall conditions areobtained by the permutation and combination method, according to the 9 rainfall frequencies and thecontrollable areas of level terrace, woodland and grassland at 10% of control progress rate. Thequality standards of level terrace, woodland and grassland are ascertained. The evaluation indexesof soil-water conservation benefits of level terrace, woodland and grassland are establishedrespectively in the condition that rainfall index is higher than that of erosive index of slopingfield. Based on the results above, the sediment reducing benefit and soil erosion modulus in thedifferent rainfall conditions and control degrees are analyzed, which could provide adecision-making basis for soil-water loss control on the Loess Plateau.展开更多
文摘Based on the distribution of hydrological stations and zoning of types ofsoil erosion, the Loess Plateau (3 10 x 10~3km^2) is divided into 292 erosion units. And taking theerosion modulus > 5000t/km^2 as a criterion, the emphasis control area (149 x 10~3km^2) of the LoessPlateau is demarked, and is divided into 10 control regions. The controllable area and the locationof control measures are conformed. Level terraces are mainly collocated on the 3° ―15° slopes,woodland and grassland are collocated on the > 15° slopes, and the proportion of woodland tograssland is 8: 2 in the forest belt, 5: 5 in the forest steppe belt, and 2: 8 in the steppe belt.The 9000 combinations of soil-water conservation measures in different rainfall conditions areobtained by the permutation and combination method, according to the 9 rainfall frequencies and thecontrollable areas of level terrace, woodland and grassland at 10% of control progress rate. Thequality standards of level terrace, woodland and grassland are ascertained. The evaluation indexesof soil-water conservation benefits of level terrace, woodland and grassland are establishedrespectively in the condition that rainfall index is higher than that of erosive index of slopingfield. Based on the results above, the sediment reducing benefit and soil erosion modulus in thedifferent rainfall conditions and control degrees are analyzed, which could provide adecision-making basis for soil-water loss control on the Loess Plateau.
