Spatial-temporal Change Of Agricultural Biomass And Carbon Capture Capability In The Mid-south Of Hebei Province

Under the influence of human activities, increased global greenhouse gases leads to adverse effects on the social, economic and natural environment. In order to slow down the global change and reduce disasters happening, many domestic and foreign experts and scholars paid lots of attention on carbon sinks and cycle research. In this area, more people study on the forest carbon sink, and fewer on farmland. As an important part of terrestrial ecosystems, farmland not only protects the human food safety, but also is an important position in carbon sinks and carbon cycle. At present, some studies showed that farmland had changed into carbon sinks from carbon source. So, research on carbon sequestration and carbon cycle in farmland is very significant which can provide theory support through tem-spatial variation characteristics of agricultural carbon capture analysis.The study area is located in mid-south of Hebei Province (MSHP), which consists of the west and east of the Taihang Mountains plain. MSHP takes important part in food producing with homogeneous underlying surface. This paper selected farmland of MSPH as a study area for the agricultural carbon sinks and cycle research. On the basis of four years land-use data (1980, 1990, 2000 and 2008) and food production (1984^-2008), agricultural biological productivity and carbon capture capacity were estimated, and their spatial-temporal characteristics of different factors were analyzed.The results showed that:From 1980s, biological productivity and carbon capture capability increased and the total amount of biomass and carbon capture reached 0.065 Pg and 0.025 Pg. Aboveground biomass increased from 600 g C·m^-2·a^-1 (in 1985) to 1200 g C·m^-2·a^-1 (in 2008), though it was affected by the decline in food production in 2003^-2005 And finally, it increased with a high speed in general. Meanwhile, farmland biomass of MSPH increased at first, then decreased and increased finally. It increased in the piedmont plains and declined in western mountains and piedmont plains spatially. he carbon capture capacity of cropland in piedmont area is 700 g C·m^-2·a^-1 to 1000 g C·m^-2·a^-1, and low plain area is smaller. Mountainous and coastal areas had the lowest capability of agricultural carbon capture. Further analysis found that the carbon capture capacity decline in piedmont and mountains, and low plains increased trend year by year. This was mainly due to improved agricultural technologies and increased investment in the low plains with higher biological yield of farmland, resulting in the low plains of farmland increased biological productivity. Developed agriculture in the piedmont, drived by human economic activities, resulted in crop production and the capacity of farmland reduced.The growth of biological productivity and carbon capture capabilities, accelerate the carbon cycle and carbon sequestration process. Although farmland is just a dynamic carbon pool , but it will increase the carbon sequestration capacity with reasonable use.