陕西省关中地区农田生态系统碳源/汇估算

运用改进的CASA(carnegie ames stanford biosphere)模型,基于化肥、农膜、农地翻耕、农机运用4类主要碳排放,结合2010年相关遥感数据和统计数据,以县(区或市)为单元对陕西省关中地区农田生态系统碳吸收、碳排放及净碳汇进行了测算。结果表明:(1)研究区碳吸收总量约为6.44×106 t,其中6,7,8月为碳吸收高值月,12,1,2,3月为碳吸收低值月。碳吸收量高于2.0×105 t的县(区或市)分布在宝鸡市北部,咸阳市西部,渭南市中部和西南部。(2)研究区碳排放总量约为1.41×106 t,农用化肥为主要碳排放源,约占89%。碳排放量超过6.00×104 t的县(区或市)分布在渭南市中部、咸阳市中部偏南。(3)研究区净碳汇总量约为5.03×106 t,各县(区或市)净碳汇量均为正值。净碳汇总量超过2.00×104 t的县(区或市)主要分布在关中地区西北部。

Carbon Source/Sink Estimation for Agro-ecosystem in Guanzhong Area

By using the related remote sensing data, statistical data and the four main carbon sources of fertilizer, agro-film, tillage and agro-machinery in 2010, a calculation of the carbon sources and sinks of agro-ecosystem in Guanzhong area was made in reference to the improved CASA (Carnegie-Ames-Stanford Biosphere) model, taking county (district or city) as a unit. The findings are as follows: (1) The total carbon absorption of the Guanzhong agro-ecosystem was about 6.44×10⁶ tons, with the high values of carbon absorption in June, July and August and the low values in December, January, February and March. The counties whose value of carbon absorption was more than 2.0×10⁵ tons were distributed in the north of Baoji City, west of Xianyang City, and middle and southwest of Weinan City. (2) The total amount of carbon emission of the Guanzhong agro-ecosystem was about 1.46×10⁶ tons. Fertilizer was the main carbon source, accounting for 89%. The regions whose value of carbon emission was more than 60 000 tons were distributed in the middle of Weinan City and mid-south of Xianyang City. (3) The total carbon sink of the Guanzhong agro-ecosystem was about 5 033 500 tons. The value of carbon sink more than 200 000 tons was centered in the northwest of Guanzhong area.