Grid scale research on Chaohu Basin's farmland fragmentation based on entire-array-polygon indicator method
Farmland fragmentation is a land use pattern contrary to land formula management. It would lead to farmland's shrinking and decentralization, and reduce the output efficiency. Carrying out spatial evaluation of farmland fragmentation is the premise and foundation of improving the land use efficiency. The paper selected Chaohu Basin as the research object, regarded 3km size grid as research unit, constructed farmland fragmentation evaluation index system based on landscape indices, and calculated each grid's farmland fragmentation using entire-array-polygon indicator method. The results show that: The area of Chaohu Basin is 19785 km2, it is divided into 2326 grids by 3km size grid. Farmland accounting for about 57% of the total area distributes in 2238 grids, which is a wide range. The space difference of farmland fragmentation in Chaohu Basin is significant. The proportion of non-fragmentation region (603 grids) is 26.94%. They mainly concentrate in the northwestern and the eastern. Slight fragmentation region (662 grids) occupies 29.58%. They scattered in the whole basin; Moderate fragmentation region (663 grids) occupies 29.62%. They mainly distributes in four districts and the surrounding area of Hefei City; Severe fragmentation region (310 grids) which has the smallest percentage about 13.85%, mainly distributes in the southwestern mountainous area of the basin. Then, there were three policy recommendations being put forward, such as vigorously prompting the development of modern agriculture, promoting the development of characteristic agriculture and forestry, weighing the construction land and the farmland. By establishing the reasonable evaluation system, measuring farmland fragmentation of Chaohu Basin and analyzing the cause of this phenomenon, we can provide recommendations for Chaohu Basin's land use and land regulation. It's beneficial for improving farmland use efficiency.