近20年来伊犁新垦区土地利用/覆被变化分析

Analysis of Land Use and Land Cover Change in the Yili Newly Reclaimed Area in Recent 20 Years

本文基于1985年、2000年和2008年3期土地利用数据,对新疆伊犁新垦区土地利用格局时空变化进行了定量研究。结果显示:1985年～2008年间,耕地净增加4.99×104hm2,面积比由38%上升至57%;未利用地增长仅次于耕地,增长面积为1.07×104hm2,水域,林地,建设用地都呈增长趋势;草地为唯一减少的土地利用类型,缩减7.02×104hm2,面积比由49%缩减为36%。通过对土地利用变化格局的分析可以得出,农业开垦是新垦区土地利用方式变化最主要的驱动力因素,草地面积减少是其他土地类型面积增加的主要来源,盐碱地增多和沼泽减少反映了该地区存在因农业开垦而导致的自然环境恶化现象。

The Yili newly reclaimed area is located in the Yili River valley,which is a main distribution area for undeveloped agricultural land in western China.Therefore,it is considered a potential area with suitable land and water resources for agricultural development,where a land consolidation and rehabilitation project supported by the Ministry of Land and Resource of China is carried out.However,due to the rapid expansion of agricultural land reclamation during past years,the land use and land cover here has been changed dramatically,resulting in a series of environment problems,such as soil erosion,land desertification and salinization.In order to provide meaningful reference for optimal land use allocation as well as environmental protection,the authors examined spatial and temporal patterns of land use over the Yili newly reclaimed area from 1985 to 2008,and further explored the major changing land use types and their transfer between each other.Remote sensing imagery,land use maps and fieldwork data were utilized in this study.Results show that from 1985 to 2008,arable land increased to 4.99×104hm2,with an increase in area percentage from 38%to 57%over the area,the largest increased amount compared with other land cover types.Unused land increased to 1.07×104hm2 in the same period,the land cover type with the second largest increase amount.It was found that among the unused land,the sandy land increased from 2.86×104 hm2 to 2.95×104hm2,and the saline-alkali land increased from 0.21×104 hm2 to 1.56×104 hm2,respectively,while marsh land deceased from 1.2×104hm2 to 0.83× 104 hm2.Water bodies,woodland and land for construction were showing increasing trend.The land use type with the most decreasing trend was grassland.It decreased to 7.02×104hm2,and is now just contributing 36%area of the study area,while contributing 49%in the year 1985.The transfer pattern among land use types during last 23 years were shown to be dramatic.The grassland is the main source for increases in other land use types.It was also found that the arable land is the land use type with the largest increasing area in the Yili newly reclaimed area,following by the land for construction.Increased sandy land primarily resulted from decreases in grassland and arable land while increased saline-alkali land was basically transferred from marsh,grassland and arable land.It was indicated that at some land use level agricultural land reclamation was the most influencing factor driving the land use change over the Yili newly reclaimed area.Thus,these changes leaded to some negative impacts on the environment.The increase in saline-alkali land and the decrease in marsh essentially reflected environment deterioration caused by an irrational development way.