Thelandcover And Soil Erosion Dynamicscharacteristicsof Mountainous Area

In order to provide references for research on process and mechanism of ecological degragation and guide scientific planning of soil and water conservation, spatial patterns and dynamic characteristics of land use/cover and soil erosion were clarified based on TM imaging data of three periods and other data and maps in Yimeng mountainous area from the spatial scales of the overall and reginal research area by technical means of remote sensing (RS), geographic information system (GIS), globle positioning system (GPS). The main results are as follows:1. Land use/cover classification system of Yimeng mountainous areaBased on GB/T21010-2007 in《classification of land present use situation》and regulations on remote sensing survey and monitoring techniques of land resource in our country, combined with research objectives and area fact, land use classification system was established.2. Land use/cover patterns and dynamic characteristics of Yimengmountainous areaDate bases of land use and plant in research area in different periods were established, space-time change laws and influencial factors of land use and soil erosion were revealed by mean of man-computer interactive based on TM image data in typical period of the year of 1987, 1997 and 2007.(1) Farmland and forest land, area of which accounted for 77.65% of the total area in this region, were the main land use structure in Yimeng mountainous area in 2007.(2) There was great change among 20 years in land use structure in Yimeng mountainous area. Area of both farmland and grassland decreased while that of forest land, town and village land, and industry and mining and traffic land increased. Meanwhile, Waters and water conservancy facilities land increased first and then decreased, which changed a little. And unutilized land showed the same changing trend as waters and water consetvancy facilities land. In addition, there were frequent conversions between farmland and forest land. And the decreased farmland mainly converted forest land, town and village land and industry and mining and traffic land.(3) As process of urbanization and industrilazation speeded up and social economy fast developed, demands of construction land would remain keep increasing, and protection pressure of resources such as farmland and forest land would futher intensify. Land use efficiency was higher, but aggregation extent of land use and plant was lower and ecological fragmentation would show intensifing trend.3. Soil erosion patterns and dynamic characteristics of Yimeng mountainous areaBased on date base of land use and plant, soil erosion was analysised, space-time change laws of soil erosion was revealed.(1) Area of soil erosion accounted for 25.67% of the total land area in Yimeng mountainous area in 2007. Moderate erosion and mild erosion were the main soil erosion types in reearch area while intensive erosion and deep intensive erosion were the main soil erosion types in local area. From the view of the distribution of soil erosion in Yimeng mountainous area, medium-low mountainous hilly ragion was the main soil erosion region, including towns of Yiyuan, Yishui, Fei, Pingyi and Mengyin, and zone of Shanting.(2) Changing characteristics of soil erosion in Yimeng area in the researched 20 years were as follows: area of soil erosion showed decreasing trend. In research area, area of mild erosion decreased first and then increased while areas of moderate erosion and above moderate erosion both decreased. In addition, fluctuate amplitude of violent erosion was largest, and deep intensive erosion was larger. In researched 20 years, soil erosion intensity exhibited overall weak trend. Area changes of soil erosion in different towns were different and their flutuate amplitudes made great differece.(3) Conversional results of soil erosion intensity and area in the researched 20 years in Yimeng mountainous area showed that area of lower intensity of soil erosion increased and that of higher intensity of soil erosion decreased during the period of the years from 1987 to 1997 while the changing trend was just opposite during the years from 1997 to 2007. As a whole, area of higher intensity of soil erosion decreased and that of lower intensity of soil erosion increased during the 20 years. That is, soil erosion in the area in the 20 years changed from higher intensity of erosion into lower intensity of erosion gradually, which showed why the total area of soil erosion decreased and the intensity of soil erosion alleviated in Yimeng mountainous area in the 20 years. However, area of mild intensity of soil erosion decreased and in local area intensive erosion and deep intensive erosion increased. Also, ecological and environmental quality showed degradating trend.