关键词: 土地评价, 土壤侵蚀, 情景分析, 土地持续利用规划, 黄土高原

Abstract:

With population growth and arable land decrease, the pressure of human activity on land resource is becoming greater. How to realize sustainable land use has become the focus of global society. Both the time scale and spatial scale have to be concerned when a sustainable land use planning was made. Normally, ecological suitability, economic feasibility and social acceptance of land use scenario have to be considered. Currently, most works concern more on theoretical aspect of sustainable land use rather than some practical approaches to realize sustainable land use. In this study, a procedure for carrying out such a planning is presented, based on results from a research project in a small catchment on the Loess Plateau. A land suitability evaluation for rainfed agriculture based on biophysical parameters, and a comparison between land suitability and current land use, were first carried out. Some potential land use scenarios, based on surveys on biophysical and socio-economic parameters in the catchment, and plans by the authorities, were proposed for further evaluation of their effects on soil erosion, economic feasibility and social acceptance. The results indicated that the following land use scenario was acceptable: all land with deep soil and slopes smaller than 15° is used for agriculture cropland, possibly combined with biological conservation measures, such as mulching combined with improved fallow, and all land with slopes steeper than 15° is used for other purposes (orchards and other cash trees, woodland, shrubland, grassland). A great reduction of on-farm income, however, would be induced on the short term by such a scenario. Local farmers will find it difficult to accept unless financial support from external sources is available. On the long term, the scenarios will be promising for both economic income improvement and soil erosion control since some production will be obtained from the conversion of cropland into orchards/cash trees (preferably on slopes 15～25°). Thus the land-use modification should be carried out gradually. On the short term (5 year), it is suggested that cropland on slopes steeper than 25° is returned to woodland/shrubland/grassland while also fruit trees are planted on slopes of 15～25°. Within 10 years, cropland with slopes steeper than 15° is suggested to be converted into orchard/woodland/shrubland/grassland.

Key words: land-use evaluation, soil erosion, scenario, sustainable land-use planning, Loess Plateau