Research On Carbon Sources And Sink And Impact Factors Of Farmland Ecosystem In Weifang

With the increase of CO2 and CH4 and other greenhouse gas emissions, gradually increased global greenhouse effect causing global warming, climate change and other ecological intense the environmental problems. The climate and environment deterioration, especially global warming has become an important challenges currently facing mankind, how to reduce the concentration of greenhouse gases in the atmosphere, and in-depth study after ecosystem carbon cycle and carbon source and carbon sink problems and other issues, become the focus of today’s research on climate change and hot issues. However, the land as the main carrier of human activities, a large number of cultivated crops, let farmland ecological system becomes the main greenhouse gas carbon sources and sinks, the crops in the use of photosynthesis and some human activities directly or indirectly to the absorption of CO2 at the same time, also through respiration of crops itself, soil and agricultural production investment brought about by the fossil fuel the consumption of raw materials such as indirect release to air CO2. And with the increase of population, improve the quality of human life, to increase farming intensity, farmland ecosystem carbon emissions will generate more. In today’s low carbon reduction of the background, studies how to realize the ecological system of farmland increase carbon sequestration in agricultural areas has become an important problem need to be solved urgently. This paper uses the data of Weifang city from 2003-2012, the main crops were collected in Weifang during the past 10 years, the output value of planting area and agricultural production input process related to pesticide, fertilizer, agricultural film, agricultural machinery, diesel and irrigation use data, system analysis of Weifang farmland ecosystem carbon emissions, carbon uptake and carbon footprint.The research results showed that:(1) according to the estimation results of farmland in Weifang city during 2003-2012 ecosystem carbon emissions and carbon absorption, from the total amount analysis, carbon: source farmland ecosystem was significantly greater than the carbon sequestration, 10 years total carbon absorption was 217359800 T, the carbon emissions of 1607439600 T, the ratio reached 1:7.4, and the farmland ecological system carbon uptake increased 10.69%, 7.02% growth in carbon emissions, the whole farmland ecological system presents carbon source system. Since the total amount of carbon emissions far exceeded the total carbon absorption, the situation was not optimistic. But from the intensity of carbon emissions and carbon absorption strength considered, the intensity of carbon emissions growth rate decreased from 0.055% to 0.048% in 10 years, while the carbon absorption strength increased, the growth rate from the original 1.18% increased to 1.98%. Carbon absorption intensity was significantly higher than that of carbon emission intensity, therefore, Weifang still had some farmland ecosystem carbon sink function.(2) to study the 12 main crop after the discovery, contribution to the farmland ecosystem of vegetables, maize, wheat was larger, the proportion accounted for 73.31% of the total carbon absorption, 12.31% and 11.68%.(3) the vegetable was the main carbon sequestration, accounted for 73.31%, irrigation was the main source of 6 carbon pathway, accounted for 87.32%. In 10 years, vegetable carbon uptake showed a trend of decreased first and then increased, as food crops brought economic benefit was low, many farmers instead low economic efficiency of food crops with higher economic benefit of vegetables and other economic crops. The rest of the crop of carbon uptake quantity was small, accounting for 2.66% of total amount of carbon absorption. The analysis found that of the six kinds of carbon emissions in the process of investment in agricultural production way, carbon emissions of agricultural irrigation accounts for the largest proportion of carbon emissions in 2012, agricultural irrigation accounts for 86.48% of the total carbon emissions, due to the increase in the effective irrigation area of arable land, caused the irrigation farmland carbon emissions growth; at the same time as the Weifang city advocate organic, green food production, the use of pesticide and fertilizer was gradually reduced, the number of carbon emissions caused by two person also gradually decreased.(4) net carbon sink of farmland ecosystem in Weifang, the year 2003 to 2012, was less than 0, the farmland ecosystem is carbon source system, and the carbon sink trend can be divided into three stages. At the same time, the overall strength of carbon sink was reducing, even annual planting area increased gradually, net carbon sink was higher, carbon absorption increased slightly with the increase of carbon emissions. Since the total amount of carbon emissions was far more than the total carbon absorption, indicating that Weifang’s energy consumption accounted for a large proportion, but also reflects the system of Weifang farmland ecosystem carbon emissions and carbon absorption of extreme imbalance. Although the use of irrigation, making Weifang ensured high yield of vegetable supply, but the farmland ecosystem carbon sink function was weakened, the situation was not optimistic.(5) carbon footprint of farmland ecosystem was reduced from 389900 hm2 in 2003 to 387690 hm2 in 2012, a reduction of 2210 hm2, the overall showed a gradual decreasing trend. The carbon footprint of the average percentage of ecological productive land area 1.456% lower proportion. 10 carbon footprint intensity mean 0.14 hm2/ RMB, Weifang’s farmland ecosystem 2003-2012 for each additional 10000 RMB output value could produce 0.14 hm2 carbon footprint. Carbon footprint intensity of Weifang city ecological system of farmland valued low, reflecting the Weifang farmland ecosystem in terms of energy use efficiency was high, the benefits of higher carbon footprint. Weifang city during the 2003-2012 10 years, carbon footprint was less than the ecological bearing capacity in the area, the difference were negative, that farmland ecological system in Weifang city was still in the carbon ecological surplus.(6) the main three factors of the farmland ecosystem carbon sources and carbon sink in Weifang were the way of land use, crop yields and agricultural production inputs; At the same time, the climate and precipitation also played an important role; And the different type of crops and soil conditions were also important to influence the carbon sources and carbon sink.