新疆绿洲区秸秆燃烧污染物释放量及固碳减排潜力

根据 2004-2013年新疆绿洲区主要作物产量,采用排放因子法对秸秆燃烧污染物排放量和碳释放量进行了估算,结果表明,2013年新疆地区作物秸秆燃烧排放的CO₂、CO、CH₄、NMVOC、OC、BC、SO₂、NO_x、NH₃和PM_2.5的量分别为9.0×10⁶ t、5.5×10⁵ t、1.6×10⁴ t、9.4×10⁴ t、1.9×10⁴ t、3.9×10³ t、2.4×10³ t、1.8×10⁴ t、7.8×10³ t和1.2×10⁵ t,碳排放总量为2.7×10⁶ t;在排放清单中,CO₂和CO是主要污染物,分别占污染物排放总量的91.6%和5.6%;棉花秸秆为排放贡献最大的污染源,占总排放量的43.3%,其次是小麦秸秆和玉米秸秆,分别占28.3%和21.9%.在此基础上,基于生物炭固碳技术,对该区域作物秸秆转化为生物炭的固碳量和碳封存潜力进行了估算,结果表明,若把被燃烧的三类秸秆(棉花、小麦和玉米)转化为生物炭,则每年可减少该区域54.9%的碳排放量;若将作物秸秆全部转化为生物炭,每年将有3.6×10⁶ t碳和1.3×10⁷ t CO₂被长期封存于生物炭中。可见,生物炭具有良好的固碳减排潜力,是一种可持续的碳封存技术。

Pollutant Releases from Crop Residue Burning and Carbon Emission Mitigation Potential by Biochar in Xinjiang Oasis

Air pollutant releases from crop residue burning were estimated based on the 2004 to 2013 yield data of major crops using emission factor method, and carbon emission mitigation potential of turning crop straw into biochar was also calculated, in Xinjiang Oasis. Results showed that amount of crop residue burned in 2013 in Xinjiang area were about 6.0×10⁶ t, yielding the following atmospheric pollutants:9.0×10⁶ t of CO₂, 5.5×10⁵ t of CO, 1.6×10⁴ t of CH₄, 9.4×10⁴ t of NMVOC, 1.9×10⁴ t of OC, 3.9×10³ t of BC, 2.4×10³ t of SO₂, 1.8×10⁴ t of NO_x, 7.8×10³ t of NH₃ and 1.2×10⁵ t of PM_2.5. The total carbon emission from crop residue burning was 2.7×10⁶ t. Carbon dioxide and CO were the major pollutants in emission inventory, accounting for 91.6% and 5.6% of the total, respectively. Cotton stalk was the largest contributor with 43.3% of total atmospheric emission, followed by wheat straw and corn stalk with contributions of 28.3% and 21.9%, respectively. Calculation showed that turning the burned crop resides(cotton, wheat and corn) into biochar could reduce carbon emission by 54.9% annually, while might sequester 3.6×10⁶ t of carbon and 1.3×10⁷ t CO_2e(carbon dioxide equivalent) over 100 years, even if biochar applications did not increase soil organic carbon content. Therefore, biochar would be an good approach to sustainable carbon sequestration.