Effects Of The Paddy Multiple Cropping Pattern On The Greenhouse Gas Emission And Soil Organic Carbon

The multiple cropping growing of paddy field is an important way to increase the grain yield,enhance the cropping index of paddy field and resource utilization rate.The study,which is based on double cropping rice and grows rape,ryegrass,milk vetch,potato during winter leisure,takes shape different multiple cropping planting patterns,such as early rice-late rice-rape?rice-rice-rape?,early rice-late rice-ryegrass?rice-rice-grass?,early rice-late rice-milk vetch?rice-rice-fertilizer?,early rice-late rice-potato?rice-rice-tubers?and early rice-regenerated rice-rape?rice-renewable rice-oil?,analyzes the effects of different winter crops on greenhouse gas emission,yield and the component factors of the early and late rice and the soil organic carbon,lays a theoretical foundation for the whole research.Mainly research results are as followings:?1?The effect of different winter crops returning on the yield of early rice was not obvious,but it had obvious effect on increasing yield of late rice.Overall,in the short term,5 winter crop treatment of rice annual total yield difference is not significant,compared with the control,the rice-rice-rape production effect is the best,for 16217.17kg/hm²,compared to the rice-rice-leisure control increased by 10%;followed by rice-rice-tuber processing?14868.49 kg/hm²?,increased by 0.86%,and other treatments did not yield significant results.?2?Winter crops returning to field also make the greenhouse gas emission increased.Compared with rice-rice-leisure,different winter crops growing patterns enhance the CH₄and CO2 emission inordinately.The CH4's emission increa-ses by 145.66%than CK,which is the highest,then are rice-rice-fertilizer?71.44%?,rice-rice-rape?17.31?,rice-renewable rice-oil?8.31%?and rice-rice-tubers?4.20%?.For the CO2's emission?compared with CK?,the results are:rice-rice-grass?27.06%?>rice-rice-rape?20.93%?>rice-rice-fertilizer?17.45%?>rice-rice-tubers?5.85%?.During the whole experiment,the N2O's emission is low overall,compared to rice-rice-leisure,the increase amplitude of the rice-renewable rice-oil,rice-rice-rape and rice-rice-tubers are 7.81%,7.43%and 6.42%.?3?Wintry crops returning to field does not have a significant effect on greenhouse gas emission in the short time.During the short time,the emission intensity under different disposes are rice-rice-grass?2.63?,rice-rice-fertilizer?1.98?,rice-renewable rice-oil?1.43?,rice-rice-rape?1.30?,rice-rice-leisure?1.19?,rice-rice-tubers?1.14?,the rice-rice-tubers is the lowest,which shows that potatoes'straw is a good crop to reduce down the greenhouse emission to some extent.?4?Winter crops returning to field can promote the accumulation of SOC in soil.Compared with the CK,all the crops returning to field improve the content of SOC,the content of rice-renewable rice-oil is 27.60g/kg,which is the highest and add up to 8.36%,then are rice-rice-grass?7.32%?,rice-rice-fertilizer?6.60%?,rice-rice-tubers?5.70%?;Among them,the soil organic carbon accum-ulation effect of rice-rice-rape was the worst,only1.63%higher than that of control.?5?Winter crops returning to field can improve the accumulation of LOC in soli.Compared with the CK,different straws of winter crops returning to field make the LOC of different layers increase,among them,the accumulation of LOC of the rice-rice-rape is6.11g/kg,which is the highest and increases by 27.58%,then are rice-rice-grass?13.83%?,rice-rice-fertilizer?10.23%?,rice-rice-tubers?0.23%?,the accumulation of LOC of the rice-renewable rice-oil is the lowest.?6?Generally,with the deepening of the soil layer,the management index of soil organic carbon pools is decreasing.Meanwhile,compared with the CK,as the experiment goes on,different winter crops returning to field improve the the management index of soil organic carbon pools,among them,the rice-rice-rape is the best and adds up to 54.99%,then are rice-rice-grass?28.35?,rice-rice-fertilizer?22.11%?,rice-rice-tubers?8.63%?,the rice-renewable rice-oil is the worst.