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作 者 ：逯非;王效科;韩冰;欧阳志云;段晓男;郑华

期 刊 ：应用生态学报 2008年 19卷 10期 页码：2239-2250

关键词：氮肥；

摘 要 ：按照2003年氮肥施用情况和农业专家对不同作物提出的推荐施肥量，设定了“氮肥施用现状”和“按推荐量施肥”两个情景，在搜集和整理全国典型的农业长期定位实验站数据的基础上，将全国划分为4个农业区，分析了两种情景下我国农田土壤的固碳潜力；同时根据我国生产氮肥的化石能源消耗以及施用氮肥的数据，采用国内以及IPCC提供的相关参数，计算了施用化肥导致的温室气体泄漏，并提出“有效固碳潜力”的概念作为评价固碳潜力有效性和固碳措施可行性的标准.我国农田土壤在两种情景下的固碳潜力分别为21.9和30.2 Tg C·a^-1；但两种情景下生产和施用化学氮肥的温室气体泄漏量分别达到了72.9和91.4 Tg C·a^-1，使两种情景下有效固碳潜力分别为-51.0和-61.1 Tg C·a^-1；而“按推荐量施肥”还将增加10.1 Tg C·a^-1的温室气体净排放.因此，施用氮肥在我国农田土壤不具备有效固碳潜力，作为固碳措施不可行.鉴于施用化肥是我国粮食安全的基本保障，建议在保证粮食生产的前提下，提高氮肥利用率，适当减少氮肥施用量，以利于温室气体的减排.

Abstract:With reference to the situation of nitrogen fertilization in 2003 and the recommendations from agricultural experts on fertilization to different crops, two scenarios, namely, ‘current situation’ and ‘fertilization as recommended’, were set for estimating the current and potential carbon sequestration of China’s cropland soil under nitrogen fertilization. After collecting and analyzing the typical data from the long-term agricultural experiment stations all over China, and based on the recent studies of soil organic matter and nutrient dynamics, we plotted China into four agricultural regions, and estimated the carbon sequestration rate and potential of cropland soil under the two scenarios in each province of China. Meanwhile, with the data concerning fossil fuel consumption for fertilizer production and nitrogen fertilization, the greenhouse gas leakage caused by nitrogen fertilizer production and application was estimated with the help of the parameters given by domestic studies and IPCC. We further proposed that the available carbon sequestration potential of cropland soil could be taken as the criterion of the validity and availability of carbon sequestration measures. The results showed that the application of synthetic nitrogen fertilizer could bring about a carbon sequestration potential of 21.9 Tg C·a^-1 in current situation, and 30.2 Tg C·a^-1 with fertilization as recommended. However, under the two scenarios, the greenhouse gas leakage caused by fertilizer production and application would reach 72.9 Tg C·a^-1 and 91.4 Tg C·a^-1, and thus, the actual available carbon sequestration potential would be -51.0 Tg C·a^-1 and -61.1 Tg C·a^-1,respectively. The situation was even worse under the ‘fertilization as recommended’ scenario, because the increase in the amount of nitrogen fertilization would lead to 10.1 Tg C·a^-1 or more net greenhouse gas emission. All these results indicated that the application of synthetic nitrogen fertilizer could not be taken as a feasible measure for the carbon sequestration of cropland soil in China. Since synthetic fertilizer application is the basic guarantee of China’s crop production, it was suggested to increase the efficiency of synthetic nitrogen fertilizer, and at the same time, to cut down the synthetic nitrogen fertilizer production and its application on the premise that the crop yield should be ensured.

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