黄土高原不同侵蚀类型区允许土壤流失量研究

为了研究中游黄土高原不同侵蚀类型区允许土壤流失量，利用黄河中游黄土高原主要侵蚀类 型区行政区划图，根据 1955—2009 年不同侵蚀类型区土壤侵蚀强度数据，分析了 12 个主要侵蚀类型 区治理期( 1970—2009 年) 和退耕后( 2000—2009 年) 较治理前( 1955—1969 年) 减沙效益。以土壤侵 蚀强度、人口密度、治理期的减沙效益以及人均纯收入为指标，利用总结的公式，将估算的不同侵蚀 类型区的总允许土壤流失量 8. 43 亿 t( T2 值) 和 7. 19 亿 t( T1 值) 合理分配到黄土高原主要侵蚀类型 区，得到不同侵蚀类型区 T2 和 T1 分配值平均值为 4 876. 2 t /( km2 ·年) 和 4 158. 9 t /( km2 ·年) 。结 合各侵蚀类型区退耕后( 2000—2009 年) 侵蚀强度及较治理期( 1970—2009 年) 减沙效益的增幅及类型 区 T2 和 T1 分配值的比例，拟定了不同侵蚀类型区允许土壤流失量 T2 和 T1 暂定值，其平均值分别为 1 200. 0 t /( km2 ·年) 和 900. 0 t /( km2 ·年) 。研究成果为黄土高原及不同侵蚀类型区水土流失治理提 供科学依据。

Study on soil loss tolerances of various soil erosion areas on Loess Plateau

In order to study the soil loss tolerances of various soil erosion areas on the Loess Plateau，the sediment reduction benefits of the harnessing period ( 1970 － 2009) and after returning the grain plots to forestry ( 2000 － 2009) in comparison with those before the harness ( 1955 － 1969) from 12 major soil erosion areas are analyzed with the administrativezoningmaps of the major soil erosion areas on the Loess Plateau along the Mid-Yellow Ｒiver according to the soilerosionintensity data of various erosion areas from 1955 to 2009. Taking the soil erosion intensity，the population density，the sediment reduction benefit of the harnessing period and the per capita net income as the indexes，the estimated total soil loss tolerances of 8. 43 × 108 t ( T2 ) and 7. 19 × 108 t ( T1 ) of various soil erosion areas mentioned above are reasonably distributed into the major soil erosion areas of the Loess Plateau with the summarized formula，thus it is obtained that the mean values of the distribution values of T2 and T1 of various soil erosion areas are 4 876. 2 t /( km2 ·a) and 4 158. 9 t /( km2 ·a) . Combined with the soil erosion intensity after returning the grain plots to forestry ( 2000 － 2009) and the increasing range of the sediment reduction benefit in combination with that of the harnessing period ( 1970 － 2009) and the proportion between the distribution values of T2 and T1 of the relevant areas，the tentative values of the soil erosion tolerances of T2 and T1 are drawn out for various soil erosion areas，of which the mean values are 1 200. 0 t /( km2 ·a) and 900. 0 t /( km2 ·a) respectively. The study result can provide a scientific basis for the soil loss harnesses of the Loess Plateau and various soil erosion areas concerned.