不同耕作方式下稻田土壤CH4和CO2的排放及碳收支估算

二氧化碳（CO2）和甲烷（CH4）是重要的温室气体，研究免耕稻田CO2和CH4排放有助于评价稻田免耕技术对全球气候变化及碳循环的影响。本文通过运用静态箱技术和田间原位碱液吸收法研究了免耕稻田土壤CO2和CH4的排放规律和排放量，及其稻田碳（C）的收支状况。研究表明，施肥提高了CH4排放，而不影响CO2的排放；免耕显著影响稻田CH4排放，而CO2的排放不受耕作影响。对稻田C收支及平衡的分析表明，施肥提高了稻田系统C的输入，同时，相对于翻耕处理，免耕处理表现为大气C的“汇”，表明了稻田免耕能将更多的碳累积于农田土壤碳库中，有利于提高稻田生态系统在减缓气温上升过程中所发挥的作用。

CH4 and CO2 Emissions from Paddy Soils and Assessment of Carbon Budget in Different Tillage Systems

Carbon dioxide（CO2） and methane（CH4） both are important greenhouse gases. It is valuable for investigating CH4 and CO2 emissions from paddy soils to assess effects of no-tillage on global climate change and C budget. Field experiments were conducted to study CH4 and CO2 emissions from paddy soils and to assess C budget in different rice tillage systems. The four treatments were no-tillage ＋ no fertilizer, conventional tillage ＋ no fertilizer, no-tillage ＋ compound fertilizer and conventional tillage ＋ compound fertilizer in rice（ Oryza sativa L. ） cultivation. Fertilization enhanced CH4 emissions but did not affect CO2 emissions. No-tillage significantly decreased CH4 emissions from rice fields but did not affect CO2 emissions relative to tilled practice. Analysis of C budget in different rice tillage systems showed that fertilization increased input of C in rice systems; moreover, no-tillage rice fields acted as C sink compared with tilled rice fields, suggesting that application of no-tillage in rice fields could lead to C sequestration in paddy soils, and thus will contribute to alleviating global warming.