Quantitative analysis of carbon trade of upland greenhouse gas emission reduction from precise fertilization

Abstract: Carbon trading is the market mechanism to reduce global greenhouse gas (GHG) emissions. Soil testing and formulated fertilization play an important role in reducing the fertilizer application and GHG emissions in intensive agricultural production area of China. In this paper, the methodology of upland GHG emission reduction in soil testing and formulated fertilization was proposed according to the basic process of carbon trade methodology. Huantai County, Shandong Province was chosen for the case study of tradable carbon calculation. The main conclusions were as follows: 1) Boundary of the project included the geolocation of upland crops and the production process of chemical fertilizers. Baseline of the project was CO2 emission in chemical fertilizer production and N2O emission in upland crop planting without soil testing and formulated fertilization, while the project activities were GHG emissions in above processes under soil testing and formulated fertilization. 2) In Huantai County, too much nitrogen and phosphorus fertilizer were added to the cropland, while potassium fertilizer was suitable. The average application amounts of nitrogen, phosphorus and potassium in wheat-corn rotation system were 515.1, 289.5 and 145.7 kg/hm2, respectively. The investigation of nitrogen fertilizer production enterprises showed that the average CO2 emission for the production of 1 t urea was 2.23 t (CO2 equivalent, the same as below). 3) The tradable carbon from soil testing and formulated fertilization was 26 485.8 t, and the farmland emission reduction, nitrogen fertilizer production reduction and phosphatic fertilizer production reduction accounted for 35.3%, 58.3% and 6.8%, respectively. Potassium production increased by 110 t emission, accounting for -0.4%. The situation was different in every town of the county because of the different crop area and fertilization. GHG reduction for Suozhen Town and Qifeng Town was 4848.6 and 6180.3 t, respectively. The main reason was that too much fertilizer was used in these 2 towns. GHG reduction in Tianzhuang, Jingjia, Chenzhuang, Xincheng, Zhoujia and Guoli was between 1700 and 2300 t. GHG reduction in Xingjia, Maqiao and Tangshan was lower than 1700 t, mainly because less fertilizer was used in these towns. 4) According to the carbon price of Shenzhen carbon trading market in March 2016, the emission reduction projects of soil testing and formulated fertilization in Huantai County could reach 12.86 million yuan, with 1.286 million yuan every year, which met the project requirement of small carbon trade. 5) The carbon trading methodology system that adopted the Denitrification and Decomposition (DNDC) model as the main measurement tool could achieve the carbon emission reduction calculation. The study has great significance to the implementation of GHG carbon emission reduction project from soil testing and formulated fertilization.