广州市农作物系统与大气的CO_2交换

The exchange of carbon dioxide between crop system and atmosphere in Guangzhou City

在广泛收集资料和实验分析的基础上,研究了广州市各种农作物系统与大气CO2交换。分析了各种农作物系统净生产力吸收CO2的能力和碳汇功能大小。结果表明:2005年广州市8种农作物系统作物净生产力吸收CO24 032 366t.a-1,其土壤CO2排放3981753t.a-1,吸收大于排放,对大气CO2而言,整个农作物系统是一个弱的碳汇;水稻、甘蔗、木薯和果用瓜4种连作或高杆作物系统每年作物净生产力吸收CO2量大于土壤CO2的排放量,系统具有较大的碳汇功能,花生、大豆、花卉和蔬菜4种矮杆作物系统每年作物净生产力吸收CO2量小于土壤CO2的排放量,系统起着碳源作用;果实或经济产量生长在地上部分的作物其单位面积吸收CO2能力比果实(块根)生长在地下的作物大;除花生在生育期间生物量吸收CO2量少于同期土壤排放以外,其余7种作物在生育期间生物量吸收CO2的量大于同期土壤排放,大多数农作物在生育期间具有碳汇功能,在撂荒期才体现碳源作用。

Base on broad collected data and experimental analysis, the carbon dioxide exchange between crop systems and atmosphere was studied in Guangzhou City. Both the CO2 absorb ability in all crop systems net productivity process and carbon sink function had been analyzed. Results showed that the CO2 absorb ability in the eight Crop systems net productivity process was 4 032 366t·a^-1 ; the amount of CO2 outlet in the soil was3981753t·a^-1 , less than the CO2 adsorb ability, so that the whole crop system was a weaker carbon sink process in the atmosphere. The continue planting species such as Rice, sugarcane, cassava, and melon crop or high haulm crops have the characteristics of annually crop net productivity CO2absorb ability bigger than soil CO2 outlet and this systems had bigger carbon sink function ability; the short haulm crop systems of peanut, soybean, flowers, and vegetable annually crops net productivity CO2 absorb ability less than soil CO2 out let, but also carbon sink source. The CO2absorb ability of fruits and economic parts above ground bigger than that which growth under ground. Except of the CO2absorb ability less than the soil CO2outlet in the peanut during growth in procreate period, the other seven crops CO2 absorb ability were bigger than that soil CO2o outlet during procreate period. Most of crops during growth in procreate period had carbon sink function ability, and only in barren period showed the carbon source function phenomenon.