Differences in soil organic carbon (SOC) distribution, water holding capacity, and soil temperature between no-tillage (NT) and conventional tillage (CT) systems can result in different soil CO2 emissions which could affect global warming but few studies have addressed this concern. An open warming experiment was conducted in situ by infrared heating of longterm conservation tillage management plots in North China Plain (NCP) to determine the effects of warming on soil CO2 emissions and the correlation to changes in soil temperature and moisture. This experiment was conducted from February 2010 to June 2012 and included CT and NT plots with and without warming. Warming treatment increased soil temperature by 2.1 and 1.5°C, and decreased volumetric soil-water content by 14 and 10% for CT and NT systems, respectively. Soil CO2 emissions tended to decrease with time in CT while it consistently increased in NT system over the three wheat seasons and two maize seasons under warming. Our results suggest that differences in soil temperature and soil moisture between the two tillage systems could be enlarged with time by warming, and the potential exist for warming to promote more soil CO2 emission under NT relative to CT. There is a need to consider the differences in response to global warming between these two tillage systems to properly assess the benefits of NT to C sequestration.
