The Analysis On The Changes Of Farmland Pattern And Its Driving Forces In Lanzhou City

Widely absorbed research achievements on the changes of cultivated land and the driving forces, taken the present landuse map of Lanzhou in 2008 and the change of land use data, the social and economic statistics in Lanzhou from 1999 to 2008 as the research basis, employed the method of the land use dynamic change model, the landscape index and principal component analysis, the paper analyzed the current situation, the processes and the driving mechanisms of temporal and spatial pattern dynamics in Lanzhou. The results as following:1) The total and per capita cultivated land in Lanzhou were continued to decline.2) The change of cultivated land in Anning district, Xigu district and Gaolan county were faster than the average of that in Lanzhou; Chengguan district, Qilihe district ,Honggu district, Yuzhong county and Yongdeng county were close to the average of that in Lanzhou. The serious loss of cultivated land resources areas were concentrated in Anning district, Xigu district and Gaolan county; The rapid loss areas were filled in Honggu district and Chengguan district; The slow loss areas were distributed in Yongdeng county, Yuzhong county and Qilihe district.3) Based on the change of cultivated land in Lanzhou to analyze its changing regularity of cultivated land landscape characteristics by landscape index. The results showed that the method of increase cultivated land was simplex, the degree of superiority was high, and the degree of evenness was low correspondingly. The ways of reducing cultivated land was more than that of increasing, the degree of superiority was low, and the degree of evenness was high correspondingly.4) Analyzed the driving forces of cultivated land changing by the combination of qualitative and quantitative analysis method. Employed the principal component analysis to study the fifteen social economic driving factors, the results indicated that the economic development, population growth, land productivity and policies were the main driving factors that affected the quantitative changes of cultivated land in Lanzhou. 5) Combined the landscape index and driving factors of cultivated land changing, proposed the specific countermeasure to protect cultivated land.