我国小麦生产主要能耗投入品相关温室气体排放研究

Greenhouse Gas Emissions from Major Energy Consumption in Wheat Production in China

我国农业生产长期以来坚持粮食主要立足国内生产的政策,在全球关注气候变化、协商温室气体减排的情况下,为保障主要粮食生产的能耗和排放需求,必须着手研究粮食生产的能源消耗和温室气体排放问题。在前人研究的基础上,本研究探索了基于农业生产投入费用成本进行能源消耗和温室气体排放估算的方法。通过分析我国种植业主要能源投入品分类统计情况,将主要的能源消耗投入品(简称主要能耗投入品)锁定在化肥、农家肥、农药、农膜、租赁作业和燃料动力,依据我国有关公开数据信息进行了分析和估算。以小麦为例的研究结果表明,我国2010年小麦生产温室气体总排放估算值3.78亿tCO2当量,单位面积排放量18.23tCO2·hm-2,其中主要能耗投入品相关温室气体排放约为0.88亿tCO2当量,单位面积排放量为4.25 tCO2·hm-2,占23.30%,其他为麦田呼吸排放量。根据小麦生产的主产品和副产品含碳量的分析,2010年小麦生产汇集约3.07亿tCO2,占小麦生产过程排放量约81.25%,净排放量约为0.71亿t,比较小麦生产过程温室气体排放和汇集能力得出,2010年小麦生产过程温室气体排放和汇集的平衡产量约为6.83 t·hm-2,低于此单产值表现为净排放,高于此单产值则表现为净汇集。案例研究表明,运用此方法可以对我国种植业生产的分年度、分农产品的能源消耗排放和汇集能力进行分析,研究结果可以为我国参加国际气候农业领域谈判、制定相关政策提供决策参考。

Agricultural production is a main source of greenhouse gas（GHG） emission. However, there is limited information available about estimates of GHG emissions from agricuhure-related energy consumption in China. Here we developed a method based on agricultural inputs and their costs to estimate energy consumption and GHG emissions in crop production. By bottom-up analysis and statistics, we found that major agricultural inputs included chemical fertilizer, manure, pesticides, plastic films, machinery and energy. In wheat production, the total GHG emissions were 378 million tons carbon dioxide equivalent, or 18.23 tons carbon dioxide equivalent per hectare in China in 2010, of which emissions from major agricultural inputs were about 88 million tons carbon dioxide equivalent, accounting for 23.30% of the total GHG emissions. The carbon dioxide absorbed by wheat was about 307 million tons in China in 2010, being 81.25% of the total GHG emissions. The net emissions from wheat production were 71 million tons. Calculation showed that the wheat yields should be 6.83 tons per hectare so that zero emissions of GHGs could be obtained in wheat production （total GHGs emissions equals total GHGs absorption by wheat）.