Soil loss tolerance （/） is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Nort...Soil loss tolerance （/） is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Northeast China, an empirically determined, default Tvalue of 200 （t/km2.a） is used for designing land restoration strategies for different types of soils. The ob- jective of this study was to provide a methodology to calculate a quantitative T for different black soil species. A field investigation was conducted to determine the typical soil profiles of 21 black soil species in the study area and a quantitative methodology based on a modified soil productivity index model was established to calculate the Tvalues. These values, which varied from 68 t/km2.a to 358 t/km2-a, yielded an average Tvalue of 141 t/km2.a for the 21 soil species. This is 29.5% lower than the current national standard T value. Two significant factors that influenced the T value were soil thickness and vulnerability to erosion. An acceptable reduction rate of soil productivity over a planned time period of 1% is recommended as necessary for maintaining long-term sustainable soil productivity. Compared with the cur- rently used of regional unified standard T value, the proposed method, which determines T using specific soil profile indices, has more practical implications for effective, sustainable management of soil and water conservation.展开更多
基金Foundation： National Natural Science Foundation of China, No.40671111 No.41101267 Nonprofit Sector Special Funds of the Ministry of Water Resources of China, No.2010332030
文摘Soil loss tolerance （/） is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Northeast China, an empirically determined, default Tvalue of 200 （t/km2.a） is used for designing land restoration strategies for different types of soils. The ob- jective of this study was to provide a methodology to calculate a quantitative T for different black soil species. A field investigation was conducted to determine the typical soil profiles of 21 black soil species in the study area and a quantitative methodology based on a modified soil productivity index model was established to calculate the Tvalues. These values, which varied from 68 t/km2.a to 358 t/km2-a, yielded an average Tvalue of 141 t/km2.a for the 21 soil species. This is 29.5% lower than the current national standard T value. Two significant factors that influenced the T value were soil thickness and vulnerability to erosion. An acceptable reduction rate of soil productivity over a planned time period of 1% is recommended as necessary for maintaining long-term sustainable soil productivity. Compared with the cur- rently used of regional unified standard T value, the proposed method, which determines T using specific soil profile indices, has more practical implications for effective, sustainable management of soil and water conservation.
