Demanding for food security and current situation of global warming give a high and strict request to North China Plain in food production and inhibition of agricultural carbon emission. To explore the effective way to decrease CO2 emission and remain high grain yield, in 2012 summer maize growing season from a long term project in North China Plain, soil organic carbon, soil CO2-C evolution rate, soil temperature, grain yield, and ratio of soil respiration to grain yield in different soil tillage and straw application treatments were invested. The results showed that in 0-20 cm soil layer, the organic carbon in no tillage was significantly higher than that in conventional tillage. Both in no tillage and conventional tillage, straw application could enhance the soil organic carbon concentrations at ma¬turity. The mean soil CO2-C evolution rate in no tillage was significantly lower than that in conventional tillage; how¬ever, straw application could significantly increase soil CO2-C evolution rate, no matter in no tillage or conventional tillage. This result was mainly due to the changes in soil organic carbon, soil total porosity, and soil temperature. No tillage and straw application result in a significantly increase in grain yield and ratio of soil respiration to grain yield of summer maize. The result obtained in field crop conditions support the idea that both no tillage and straw application affect CO2 emissions in North China Plain
