Abstract:

 The importance for harmonious relationship between the people and land in China has now been fully recognized as China has a high percentage of hilly fields and a low percentage of cultivated lands. The Yangtze Basin is a major region with low mountains and hilly areas. By constructing models of population quantities and the land resource yield potentialities and selecting methods for environment capacity rank division and its coefficients calculation, the influence of land use types and their changes on the land loading capacity in hilly and mountainous regions in the upper reaches of the Yangtze Basin has been evaluated in this paper. The population quantities and the land resource yield potentialities in 2010, 2015 and 2020 were calculated respectively for Yibin City. The ability for loading population and land loading ability were further estimated according to nutrient structures required by three living types, i.e. tolerably well off type, moderately well off type and relatively well off type. It is indicated that land yield potentialities could bear population quantity of every living types in 2010, 2015 and 2020, and land resource population capacity ranks in Yibin City could attain “sufficiency” level with the ranking score being “3” and a tendency towards “abundance” level. Land loading ability in Yibin City which has a potential and an improving margin can be a positive driving factor for regional economical development, with the influence of human activities on land loading capacity being under the threshold value. The reliable scientific foundation was then established for the construction of ecological environment and for the development of vast hilly and mountainous regions in upper reaches of the Yangtze Basin.

Key words: the Yangtze Basin, hilly and mountainous region, land resource, land loading capacity, Yibin City