应用生命周期法评价我国测土配方施肥项目减排效果

近年来,我国大力推广测土配方施肥,有效改善了不合理施肥现象。研究测土配方施肥技术的节肥、减少温室气体排放效果,旨在为编制农田温室气体排放清单和制定农业减排对策提供依据。通过查阅相关文献估算我国测土配方施肥技术的节约氮肥量,应用生命周期评价(LCA)方法评估其减排效果,农田减排量依据《2006IPCC国家温室气体排放清单编制指南》提供的方法进行估算,工业生产过程的减排量依据Specific(primary) energy consumption(SEC)方法进行估算。结果表明:我国实施测土配方施肥技术可节约氮肥(27.23±7.42) kg N·hm^-2;到2013年,测土配方施肥技术总计减排量达到了2 500.35万t CO₂-e,其中由于氮肥田间施用量的减少导致农田总共减排1 171.83万t CO₂-e,由于工业生产氮肥量的减少而节约标煤583.45万t,减排1 328.52万t CO₂-e。测土配方施肥技术不仅可以节约氮肥用量,还可以降低温室气体排放量,因而应加大投资力度,扩大测土配方施肥面积,同时对测土配方施肥技术的适用性和经济性进行评价,进一步提高测土配方施肥技术的节肥减排效果,增强农业减排能力。

Evaluation of Greenhouse Gas Emission Reduction by Balanced Fertilization in China Using Life Cycle Assessment

In recent years, China has actively been promoting the technology of balanced fertilization, which has greatly reduced unfavorable effects of fertilization. Studying the effects of this technology on the minimization of nitrogen fertilizer use and the reduction of greenhouse gas emission would provide the basis for establishing inventory of farmland greenhouse gas emissions and proposing measures for agricultural greenhouse gas emission reduction. In this study, data from the relevant literatures was used to estimate the amount of nitrogen fertilizer saving by balanced fertilization. Life Cycle Assessment(LCA) was used to evaluate the reduction of greenhouse gas emissions by balanced fertilization. The amount of emission reduction in farmlands and industrial processes was estimated by the methods used in the 2006 IPCC Guidelines for Nation Greenhouse Gas Inventories and the specific(primary) energy consumption(SEC), respectively. Balanced fertilization reduced the use of nitrogen fertilizers by (27.23±7.42)kg N·hm^-2. In 2013, the total emission reduction by balanced fertilization was 25 003 500 tons CO₂-e, of which 11 718 300 tons CO₂-e was from farmlands. Of farmland sources, 10 142 100 tons CO₂-e was direct N₂O emission reduction and 1 576 100 tons CO₂-e from reduced nitrogen volatilization and leaching/runoff. Industrial processes contributed to the reduction of 13 285 200 tons CO₂-e from the conservation of 5 834 500 tons standard coal by reduced nitrogen fertilizer production. Implementing balanced fertilization could reduce nitrogen fertilizer use and thus greenhouse gas emissions.