Soil
erosion is one of the most important land degradation in China.
Land quality indicators based on “Press-State-Response” framework can explore distinctively the reason and the results of land quality changes, which will help administrator to adopt suitable land policy and management measures to rehabillitate degraded land and improve land quality. Respectively taking cell (10m×10m) and whole
catchment as evaluation unit, Land quality indicators based on
PSR framework for soil degradation by water erosion were build up at Da Nangou catchment, Shaanxi province, hilly area in Loess Plateu. In the former land quality indicator (cell as evaluation unit), slope gradient is used as a press indicator, state indicators include
Soil erosion intensity,
Soil fertility and vegetation cover, response indicator is the land use type. As for the latter (whole catchment as evaluation unit), the press indicators include topography, cultivation, crop income and land use pattern; state indicators include soil erosion intensity, soil fertility, vegetation cover and soil and water loss indicators at catchment exit; response indicators include the proportion of the area of non-farmland (forest/shrub + grassland + fallow) to whole land and terrace land to whole farmland. Land qulity status of the catchment were evaluated based on land use in the year of 1998 by the application of model simulating and statistical analysis.Average slope gradient in the small catchment is 27.85°, the maxium gradient is 59.39°, the average gradient for farmland is 24.56°, the proportion of the area of farmland to whole land is 42.8% and the income proportion from crop is about 63%. We divide the land quality of the catchment into six grade and the pressure evaluation is fifth; the average soil erosion intensity and the total erosion is respectively 36.39t/ha and 6.03t/ha at the catchment exit. The average vegetation cover is 2.83%; the state grade is fourth; the area proportion of non-farmland to whole land is 57.2% and the terrace land to whole farmland is 4.01%, the response grade is also fourth. Spatial heterogeneity of land quality at catchment is low, the fourth grade land occupied almost the percent 50 to the total catchment area. Land quality is different among land use types. The order from high to low of land quality is respectively forest/shrub, grassland, orach/economic forest, fallow and farmland. The results will provide some useful information for land planning in valley and land quality comparision among different valleies.
More summaries about the Land quality indictors based on “Press-State-Response” framework at catchment for soil degradation b