Spatial-temporal pattern of net carbon sink of farmland vegetation in Jiangsu Province

Abstract: Scientific research on net carbon sink and its spatial-temporal pattern of regional farmland vegetation is of great significance to take reasonable agricultural management measures and to achieve the goal of reducing carbon source and increasing carbon sink of farmland ecosystem. Taking 13 prefecture-level cities in Jiangsu Province as the research areas, we estimated the net carbon sink of farmland vegetation by using relevant statistical data such as crop yields and farmland investments from 2000 to 2015. By the aid of migration of gravity center and spatial autocorrelation methods, we also analyzed the spatial-temporal pattern of net carbon sink. The results showed that: 1) The total net carbon sink of the farmland vegetation within all cities in Jiangsu was positive, and the total net carbon sink in northern and central Jiangsu Province showed an upward trend while that in southern Jiangsu was in a downward trend. The amount of net carbon sink of farmland vegetation was shown as northern Jiangsu > central Jiangsu > southern Jiangsu. The net carbon sink intensity of farmland vegetation had a rising trend, and in terms of spatial distribution the highest area was central Jiangsu, the moderate was northern Jiangsu, and the lowest was southern Jiangsu. In the past 16 years, the gravity center of net carbon sink of farmland vegetation was basically located in Baoying County, Jiangsu Province, and moved northwestward in general with a distance of 27.68 km. The overall pattern of net carbon sink of farmland vegetation remained relatively stable, with the spatial characteristics of "north hot and south cold", indicating an obvious geographical agglomeration phenomenon. The total net carbon sink of farmland vegetation in coastal areas and inland areas of Jiangsu Province was significantly higher than those areas along the Yangtze River. The proportion of hot spots increased from 30.77% in 2000 to 38.46% in 2015, while the cold area decreased from 30.77% in 2000 to 23.08% in 2015. In conclusion, the farmland vegetation in Jiangsu Province showed a strong capacity of carbon sink in the past 16 years. Northern Jiangsu and central Jiangsu will be the main potential areas of net carbon sinks in farmland vegetation of Jiangsu Province in the future. Different cities in Jiangsu Province can formulate different measures of agricultural management in order to function as the ecological barrier of the farmland ecosystem.