The Study On Carbon Emission Efficiency At Different Intensive Utilization Levels Of Cultivated Land In Hebei Province

With the continuous social and economic development in China, the utilization of cultivated land has also continually expanded from breadth to depth and its production efficiency and scale has increased gradually. At the same time, the carbon dioxide emissions from fertilizers, pesticides, electricity, fossil fuels used in cultivated land utilization activities have a rapid growth. So the agricultural production has become an important source of greenhouse gases. Our country is a large agricultural country, guaranteeing food and security and developing agriculture vigorously is a basic national policy. Under the condition that technical level is relatively stable; the increase in carbon source will inevitably lead to increased carbon emission scale. The study on carbon emission efficiency of the cultivated land utilization is important to control carbon emissions, improve agricultural input-output ratio, and guide the rational and efficient use of agricultural. This paper takes Hebei Province as an example, uses GIS spatial analysis techniques to analyze the intensive utilization degree and the temporal and spatial change of carbon emission efficiency of cultivated and then analyzes the change rule of carbon emission efficiency under different intensive utilization of cultivated land. By studying that, we draw the following main conclusions:(1) We filter the carbon source by use of life cycle assessment, build accounting system of carbon emissions and measure the carbon emissions of cultivated land in Hebei Province during1990-2010.We find that the carbon emissions and carbon intensity of cultivated land can be divided into three periods which conclude the rapid growth period, the slow growth period and the slowdown period. In terms of its internal structure, the use of fertilizer and agricultural irrigation are major sources of carbon emissions of cultivated land. The intensity of carbon emissions is relatively high in the plain area but comparatively low in Bashang plateau area because of its unique topography, landscape and other factors.(2) From the perspective of input and output, we construct a calculation model of carbon emission efficiency of cultivated utilization based on input-orientation, use the model called maxdea to calculate the total carbon emission efficiency of cultivated land use, technical efficiency and scale efficiency. During 1990-2010, the carbon emission efficiency of cultivated land has been fluctuating and its value is at a low level, meanwhile it shows a trend of overall efficiency < technical efficiency < scale efficiency. The effective area of the carbon emission total efficiency concentrates mainly in the Bashang plateau area and the mountains and hills area, whose inputs and outputs are all in the optimal state. The total carbon emission efficiency is relatively low in the areas where economy develops fairly well such as Shijiazhuang, Xingtai and Tangshan.(3) By the use of spatial analysis software called Geo Da, we analyze the spatial correlation between the intensive utilization and carbon emission efficiency of cultivated land and make a further analysis of change rule of the carbon emission efficiency at different intensive utilization levels. It shows that the intensive utilization and carbon emission efficiency of cultivated land have a negative correlation in Hebei Province during1990-2010, the partial aggregation has been increasing as time goes by, the HL gathering area of intensive use and carbon emission efficiency includes the piedmont plain area located in the Shijiazhuang, the east of Baoding and the southeast of Handan; the LH gathering area of intensive use and carbon emission efficiency includes most area of Zhangjiakou and Chengde, has a trend extending to the south and east of Hebei Province taking Zhangjiakou as the center as time goes by. From the view of change in average carbon emission efficiency under different intensive utilization levels, we find that with the rise in the level of intensive use of cultivated land, the carbon emission efficiency of cultivated land every year shows a change trend: the first-order zone of cultivated land intensive utilization>the second-order zone>the third-order zone > the fourth-order area.