EFFECTS OF PLANTING SYSTEMS AND STRAW MULCHING ON CARBON EMISSIONS AND WINTER WHEAT GRAIN YIELD IN THE NORTH CHINA PLAIN

To explore effective ways to decrease soil CO2 emission and increase winter wheat grain yield in the North China Plain, a field experiment was conducted using two planting systems (wide-precision planting and conventional-cultivation planting) and two straw mulching rates (0 and 0.6 kg m(-2)) to study carbon emission, carbon cumulative emission flux, grain yield and yield carbon utilization efficiency. In the 2013-2014 and 2014-2015 winter wheat growing seasons, CO2 emission rate and cumulative CO2-C fluxes following straw mulching treatment were significantly lower than those following nonmulching treatments, whereas the yield carbon utilization efficiency was significant higher following straw mulching treatment. Straw mulching significantly reduced winter wheat grain yield, which was mainly due to the significant decrease in spike numbers and 1000-kernel weight. However, wideprecision planting system significantly increased winter wheat grain yields by increasing spike numbers under straw mulching conditions. Therefore, wide-precision planting system could compensate for the reduction in winter wheat grain yield under carbon sequestration conditions in the North China Plain.