Abstract:

【Objective】 Field experiment was carried out to estimate tillage effects on soil CO2 emission, relative contribution of root and soil respiration and carbon balance, and carbon respiration intensity during winter wheat growth season. 【Method】Conventional tillage (CT), rotary tillage (RT), and no tillage (NT) were used during 2006-2008, soil CO2 emission was measured by using static closed chambers and root contribution of root respiration was detected by root exclusion method. NEP was calculated for estimating carbon sequestration intensity. 【Result】 Soil CO2 emission was affected significantly by different tillage systems and it showed a significant seasonal fluctuating characteristic which was dropping until reached the lowest in hibernation and hoisting during the following period. The order of mean soil CO2 emission rate was CT＞RT＞NT. The mean ratio of root respiration contributed to total respiration was 26.18%, 29.96% and 36.44% under CT, RT and NT, respectively. The contribution ratio of rhizospheric respiration to total soil CO2 emission was fluctuated from 15% to 85% during the season and the ratio was highest at jointing stage of winter wheat under each tillage system. 【Conclusion】 Therefore, soils were sinks of atmospheric CO2 under each tillage system, but the order of the intensity of carbon sink was NT＞RT＞CT.

Key words: tillage')">tillage, winter wheat, CO2 emission, root respiration, carbon balance