| With the different stages of social and economic development,the phenomenon of abandonment of arable land shows different trends and patterns.In the past three decades,abandonment of arable land has become more and more common in China.Abandonment of arable land not only affects regional grain production capacity,restricts the comprehensive development of rural economy,but also affects the local ecological environment to a certain extent.Sustainable arable land use and sustainable rural income are important prerequisites for sustainable rural development.It is very important for achieving precise poverty alleviation,Rural Revitalization and ecological construction to study the abandonment of arable land,especially in poor mountainous areas,to analyze the changing law of abandonment,and to find out the internal causes of abandonment.Anding District,located in Dingxi City,Gansu Province,is a typical semi-arid mountainous agricultural climate area.This paper takes Anding District as the research area,the spatial and temporal distribution pattern of abandoned arable land is extracted and analyzed based on Landsat series image data from 2006 to 2018.The distribution of abandoned arable land in different locations is analyzed from four aspects:altitude,slope,convenient conditions of field roads and cultivation distance.The results are as follows:(1)According to the cultivated land system and farming habits in the study area,the cultivated land without crops for three consecutive years is defined as abandoned land.(2)The overall classification accuracy of the image is verified by the confusion matrix.The overall classification accuracy is between 85.4%and 92.3%,and the Kappa index is between 0.82 and 0.9.(3)The phenomenon of abandonment of arable land in Anding District in recent ten years is more serious,with an average annual abandonment rate of 12839 hm~2 and an average annual abandonment rate of 9%.The abandonment of arable land fluctuates regularly,but the fluctuation range decreases year by year.The abandonment of arable land in 2009 and 2011 is the most serious,with the abandonment rate reaching 13.12%and13.05%respectively.In 2016,abandonment of arable land is the least,with a abandonment rate of 4.7%.(4)Based on the cultivated land in 2006,5846.38 hm~2 cultivated land has been abandoned for 12 years,accounting for 3.44%of the total cultivated land area;6896.89hm~2 cultivated land has been abandoned for 10 years,accounting for 4.05%of the total cultivated land area;14 325.03 hm~2 cultivated land has been abandoned for less than five years,accounting for 8.43%of the total cultivated land area.(5)The cultivated land in Anding District is most likely to be abandoned when its elevation is 2000-2150m,slope is 6-15°and distance from roads and residential areas is200 meters.The abandoned wasteland between 2000-2150m above sea level accounts for53%of the total abandoning arable land annually,the lowest accounts for 46%of the annual abandoning arable land,the highest accounts for 60%of the annual abandoning arable land;the abandoning arable land between slope 6-15°accounts for 55.8%of the total abandoning arable land annually,the lowest accounts for 44.21%of the annual abandoning arable land,the highest accounts for 63.37%of the annual abandoning arable land;the abandoning arable land above 200 m distance from roads accounts for 60.38%of the total abandoning arable land annually,the lowest accounts for 57.82%of the annual abandoning arable land,and the highest accounts for 64.30%of the annual abandoning arable land;the abandoning arable land over 200 meters away from the residential area accounts for 72.9%of the total abandoning arable land,the lowest accounts for 67.95%of the annual abandoned land,and the highest accounts for 80.38%of the annual abandoning arable land. |
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