Net Greenhouse Gas Balance in China鈥檚 Croplands over the Last Three Decades and Its Mitigation Potential

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• 作者：Wen Zhang ; Yongqiang Yu ; Tingting Li ; Wenjuan Sun ; Yao Huang
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：March 4, 2014
• 年：2014
• 卷：48
• 期：5
• 页码：2589-2597
• 全文大小：476K
• 年卷期：v.48,no.5(March 4, 2014)
• ISSN：1520-5851

文摘

Cropland soils have been shown to emit nitrous oxide (N₂O) and methane (CH₄) into the atmosphere and to sequester carbon when field management is improved, yet the spatiotemporal changes in the N₂O and CH₄ emissions and the soil organic carbon (SOC) in China鈥檚 croplands are unclear with regard to an integrated global warming potential (GWP). This limits our overall evaluation of anthropogenic greenhouse gas (GHG) emissions and impairs effective decision making. On the basis of model simulations primarily from 1980 to 2009, we estimated a 69% increase in the gross GWP of CH₄ and N₂O emissions, from 244 Tg CO₂-equiv yr^鈥? in the early 1980s to 413 Tg CO₂-equiv yr^鈥? in the late 2000s. The SOC was estimated to have increased from 54 Tg CO₂-equiv yr^鈥? to 117 Tg CO₂-equiv yr^鈥? during the same period. A reduction in the carbon input during the rice season, along with an improvement of synthetic nitrogen use efficiency in crops to 40%, would mitigate GHG emissions by 111 Tg CO₂-equiv yr^鈥? and keep SOC sequestration at 82 Tg CO₂ yr^鈥?. Together, this would amount to a reduction of 193 Tg CO₂-equiv yr^鈥?, representing 47% of the gross GWP in the late 2000s. The mitigation of GHG emissions in Henan, Shandong, Hunan, Jiangsu, Hubei, Sichuan, Anhui, Jiangxi, Guangdong and Hebei Provinces could lead to a 66% national improvement and should be given priority.