摘要
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.
Based on the distribution of hydrological stations and zoning of typ es of soil erosion, the Loess Plateau (310×103km2) is divided into 292 erosion units. And taking the erosion modulus >5000t/km2 as a criterion, the emphasis co ntrol area (149×103km2) of the Loess Plateau is demarked, and is divided into 1 0 control regions. The controllable area and the location of control measures ar e conformed. Level terraces are mainly collocated on the 3°-15°slopes, woodla nd and grassland are collocated on the >15°slopes, and the proportion of woodla nd to grassland 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 measu res in different rainfall conditions are obtained by the permutation and combina tion method, according to the 9 rainfall frequencies and the controllable areas of level terrace, woodland and grassland at 10%of control progress rate. The qu ality standards of level terrace, woodland and grassland are ascertained. The ev aluation indexes of soil-water conservation benefits of level terrace, woodland and grassland are established respectively in the condition that rainfall index is higher than that of erosive index of sloping field. Based on the results abo ve, the sediment reducing benefit and soil erosion modulus in the different rain fall conditions and control degrees are analyzed, which could provide a decision-making basis for soil-water loss control on the Loess Plateau.
基金
UndertheauspicesoftheNational973Project(2002CB111502),andtheKnowledgeInnovationProjectofChineseAcademyofSciences(KZCX1-10-04).
