Study On Land Use Change And Benefits Of The Grain

The Grain for Green Project(GGP)is an important ecological engineering project of China’s western development strategy.It is of great significance to improve the ecological security,economic stability and social development in the north by adjusting the land use structure.In this paper,we used 3S technology to understand the land use change in Hohhot in 2000,2010 and 2018,analyze the change characteristics of slope and farmland product potential of GGP,explore the change of eco-environmental Index to show the eco-environmental quality change caused by GGP in Hohhot.The results show that:1.From 2000 to 2010,the trend of land use in Hohhot showed a decrease of grassland and cultivated land,and a increase of forest land and construction land;From 2010 to 2018,the area of construction land increased significantly,and the area of cultivated land,grassland and unused land decreased.From 2000 to 2010,Helingeer and Wuchuan had the largest area of farmland conversion;From 2010 to2018,the grassland,cultivated land and unused land of each county showed a downward trend,and the reduction of cultivated land area was mainly concentrated in the Hohhot main district,Wuchuan and Tumotezuoqi.2.From 2000 to 2010,the area of returning farmland to forest land was 100.86km~2,Mainly forest land,accounting for 81.16%;The area of forest land is the largest in Helingeer,and the area of shrub forest is the largest in Wuchuan;The area of returning farmland to grassland is 217.21 km~2,Low cover grassland accounted for69.48%,mainly concentrated in Wuchuan and Helingeer.From 2010 to 2018,the total area of returning farmland to forest was 20.68 km~2,Mainly forest land,accounting for 73.87%,Tumotezuoqi has the largest area;The area of returning farmland to grassland is only 2.35 km~2。3.In 2000年-2010年,95.17%of the farmland returned to forest in Hohhot had a slope of 0°-15°;From 2000 to 2010,97.9%of the farmland returned to grass land in Hohhot had a slope of 0°-15°.These areas are mainly in Wuchuan and Helingeer.From 2010 to 2018,85.34%of the farmland returned to forest land with a slope of 0°-2°was concentrated in the municipal district,Tuoketuo and Tumotezuoqi;For the grassland mainly in 0°-15°,accounting for more than 95%.4.GGP in Hohhot from 2000 to 2010,the farmland product potential is mainly under 2000kg/hm~2,takes 90.69%and 92.72%of the farmland to forest and grassland respectively;from 2010 to 2018,the farmland product potential of returning farmland to forest in Hohhot are mainly in three classes:under 2000kg/hm~2、2000-4000Kg/hm~2and 4000-6000Kg/hm~2,take 31.59%,40.01%and 22.73%of farmland to forest respectively;As for returning farmland to grassland,the farmland product potential are mainly in two classes:under 2000kg/hm~2and 2000-4000kg/hm~2,accounting for 83.27%and 14.33%of returning farmland to grassland respectively.5.The total eco-environmental index of the study area increased first and then decreased.In terms of the ecological value of returned farmland,the ecological value of returned farmland increased by 1.397×10~8yuan in the year of 2000 to 2010;From2010 to 2018,the ecological value of returned farmland increased by 2.741×10~7yuan.Among them,gas regulation,climate regulation,water conservation,soil formation and protection,biodiversity protection,raw materials and entertainment culture were increased;The value of food production and waste disposal decreased.From the perspective of ecological contribution rate,more than 95%of the growth of eco-environmental index are contributed by returning farmland to forest.6.According to the comprehensive evaluation model,the results show that the ecological benefit level of Hohhot is"general",the social benefit level is"good",and the economic benefit level is"good";The comprehensive benefit level is"good".Therefore,the project of returning farmland to forest and grassland in Hohhot is worth popularizing and developing.