| The cultivated land is the core of the land use and its dynamic change is the reflection of the economic development in regional scale. Langfang is in the high economic region and has a different location from the other cities, so its change of cultivated land and the driving forces have the regional traits. On the basis of drawing the achievements in research of cultivated land use change and driving forces and taking the maps which are about the land use and layout of Langfang and the Plan District of Langfang and the data which are about the change of land use and the social economy for the investigative basis. By using the software of MAPGIS and the quantitative and qualitative methods, the paper analyzes the area, dynamic change and spatial change of cultivated land from 1987 to 1996 in Langfang and from 1996 to 2002 in the Plan District of Langfang. At the same time combining the landscape software of Fragstats analyzes the landscape change of study area. Finally through choosing the proper human driving forces and using the method of principal analysis of SPSS, the paper discusses the main human driving forces that cause the change of cultivated land in Langfang and the Plan District of Langfang in different time in order to know the regularity of cultivated land in research area. The results showed:(1) In the land use frame of Langfang, the area of cultivated land, forest land and none-use land decreased, but the residential- industrial land, garden plot, water area and traffic land had different increase. Garden plot had the biggest annual change rate, cultivated land had the most synthetical change rate. In the Plan District of Langfang cultivated land, forest land and non-use land decreased in different degree, other types of land increased. The biggest annual and synthetical change rate of land was none-use land.(2) During the ten years cultivated land in Langfang decreased annually. The main decrease flow of cultivated land was residential and industrial land, the rate was 46.06%;the subsequent flow was the change of agricultural frame, water plot and traffic land et al. The main increase of cultivated land was from forest land and non-use land, the rates were 28.13% and 27.50%. Cultivated land in the Plan District of Langfang decreased obviously during the seven years, the main reduction of cultivated land was residential- industrial land, the rate was highly 98.04%.The main increase of cultivated land was none-use land, the rate was 91%.(3) The landscape in Langfang was that the fragment, the dispersed degree of the different patches and the shape complexity was increased and the connection of the same patches and the preponderant landscape was decreased. On the class scale, cultivated land had the same characteristic as the landscape. The Plan District of Langfang had a different landscape to the Langfang. Its characteristic was that the fragment was decreased and the shape of patches was simple. The class of cultivated land developed tothe convergence and the uniform aspect. Irrigable land was the main type of cultivated land, the class metrics showed the increase of the fragment and the dispersed degree et al.(4) Through the principal analysis method of SPSS, the paper quantificationally analyzed the relativity during the driving factors of economy, people, urbanization, agricultural technology and the radiation of cities. Meantime the paper analyzed and described the driving process. The main conclusions were that the effect of agricultural technology factor decreased and the non-agricultural economy enhanced. By using the model in the paper, the author tried to show the radiation of cities to the cultivated land of the Plan District of Langfang in the small scale. The calculating results that the modulus of Beijing and Tianjin were 12.6 and 7.9. Beijing had a deeper effect to the cultivated land in the Plan District of Langfang than Tianjin. |
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