长江上游山丘区土地承载力研究与评价——以四川省宜宾市为例

EVALUATION OF THE LAND LOADING CAPACITY IN HILLY AND MOUNTAINOUS REGIONS IN THE UPPER REACHES OF THE YANGTZE BASIN——THE CASE OF YIBIN CITY IN SICHUAN PROVINCE

我国是一个以山地为主的国家,耕地有限且以山丘坡耕地为主,协调人地关系非常重要。以四川省宜宾市为例,通过土地资源生产潜力和人口数量预测模型的建立,采用环境容量等级系数计算和等级划分方法,对基于水土流失和生态工程建设作用下的长江上游流域山丘区土地利用类型与格局的变化及其它人类活动对土地承载力的影响进行了研究与评价。研究结果表明,宜宾市土地资源的生产潜力在2010、2015、2020年时总体上都能承载3种生活类型条件下的人口数量,3种生活类型下的容量等级基本都在“3”以上,即达到“满足”水平,并呈现出向“富余”水平提高的趋势,这表明尚具有较大潜力和空间的土地承载力是宜宾区域经济发展的有利驱动因素,人类活动对土地承载力产生的影响在可承受的生态阈值之内,为长江上游流域及我国广大山丘地区的生态环境建设和区域发展提供了可靠依据。

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 type＇s 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.