Effects Of Different Straw Addition Methods On CO₂Emission And Organic Carbon Accumulation Of Chernozem

The application of corn straw is the main method of fertility for tillage on chernozem inSongnen Plain. In order to reveal the fertility and environmental effect between the ploughing ofCorn straw returning and mulching of Corn straw returning. Chernozem was selected as soilsample, Corn was used as organic material.The simulative incubation experiment was designedto study the effects of the different straw application on CO2emission and organic carbonaccumulation.1. The results showed that the emission rate of CO2achieve to maximum on the4th or6thdays for all the treatments under the experimental conditions, the curves had the first slowemission platform on13-52days. the second slow emission of CO2emission platform appearedon52-91days. The Peak value of CO2emission rate of “straw mixing” was apparently greaterthan that of “straw mulching”, However, after entering the slow emission platform, the averageemission rate of CO2of “straw mixing” was apparently less than that of “straw tile”. The curveof CO2emission rate of “straw mixing” and “straw mulching” existed an apparently intersectionpoint, the CO2-C accumulation emission amount of “straw mixing” were greater than that of“straw mulching” before intersection point, and less than that of “straw mulching” afterintersection. The analysis showed that contrasted with “straw mulching”“straw mixing” couldincrease more soil organic content and had the better effect on micro-aggregate compositiondevelopment with the same amount of straw condition.2. The results showed that the emission rate of CO2achieve to maximum on the4th or6thdays for all the plus calcium carbonate treatments under the experimental conditions, the curveshad the first slow emission platform on16-52days. the second slow emission of CO2emissionplatform appeared on52-91days. The Peak value of CO2emission rate of “calcium carbonate”was apparently greater than that of “straw mixing”. The sequence of CO2-C accumulationemission amount of1%exogenous calcium carbonate combined with “straw mixing” showedthat0.6%of straw>0.4of straw>0.2of straw.3. The dynamic of carbonate content is: CK had the largest amount of carbonate, CK>0.2%of straw mulching>0.4%of straw mulching>0.6%of straw mulching and CK>0.2%ofstraw mixing>0.4%of straw mixing>0.6%of straw mixing, calcium carbonate content ofstraw mulch was great than that of straw mixing, the dynamic of carbonate of1%exogenouscalcium carbonate combined with “straw mixing” showed that CK>0.2%>0.4%>0.6%. 4. The result can be concluded that the corn straw applied to soil by the measures ofincorporation and rotary tillage can bring better fertilization and environment effect than that ofstraw mulching. The analysis showed that contrasted with “straw mulching”“straw mixing”could increase more soil organic content, soil microbial carbon and had the better effect onmicro-aggregate composition development with the same amount of straw condition. The resultcan be concluded that the corn straw applied to soil by the measures of incorporation and rotarytillage can bring better fertilization and environment effect than that of straw mulching in themajor corn producing areas of the Northeast.