采用静态箱-气相色谱法观测了我国南方亚热带水稻田转为旱作蔬菜地后第1年的CO_2和CH_4通量变化,旨在探索稻田转菜地初期对CO_2和CH_4通量的影响.结果表明:CO_2通量因蔬菜种类、生长状况及生长季节的不同而不同.种植豇豆菜地CO_2通量显著高于稻田,种植辣椒菜地CO_2通量则显著低于稻田.稻田转菜地CH_4通量从6.96 mg C?m~(-2)?h~(-1)显著下降到-0.004 mg C?m~(-2)?h~(-1)(P<0.001).转菜地后CO_2和CH_4的净累积碳吸收为543kg C?hm~(-2),显著低于稻田的3641 kg C?hm~(-2),但由净CO_2和CH_4排放造成的增温效应无显著差异.转成菜地1年后的土壤有机碳含量有所升高,且10~20 cm土层显著高于对照水稻田.
英文摘要:
In this study,the CO_2 and CH_4 fluxes in the first year after land use conversion from paddy rice to vegetables were measured by static opaque chamber and gas-chromatograph (GC) method to investigate the land conversion effects on soil CO_2 and CH_4 emissions. Our results showed that the differences in CO_2 fluxes depended on the vegetable types,growing status and seasons. The CO_2 flux from the vegetable field was greater than that from the paddy rice field when cowpea was planted,but was lower when pepper was planted. The CH_4 flux significantly decreased from 6. 96 mg C?m~(-2)?h~(-1) to -0. 004 mg C?m~(-2)?h~(-1) with the land use conversion from rice to vegetables. The net carbon absorption (CO_2+ CH_4) of the vegetable fields was 543 kg C?hm~(-2),significantly lower than that (3641 kg C?hm~(-2)) of the rice paddies. However,no significant difference was found in their global warming impact. In addition,soil carbon content increased in vegetable fields compared to the paddy rice fields after a year of conversion,especially in the 10-20 cm soil layer.