Effects Of Nitrogen-rich Biochar On Carbon Storage And Carbon Based Greenhouse Gas Emissions From Paddy Field Ecosystems In Fuzhou Plain

CO₂ and CH₄ are the main carbon-containing greenhouse gases,and their concentrations are the main cause of climate warming.Paddy field ecosystems are the major source of greenhouse gas emissions and significant part of the global carbon pool.Paddy field carbon sequestration research has important theoretical and practical significance for the sustainable production of regional agriculture.Based on this,in order to explore the changes in the flux of carbon in greenhouses and carbon-based greenhouse gases under the application of nitrogen-rich biochar.This study uses the paddy field in Fujian Province as a sample plot,by setting different amounts of nitrogen-rich biochar 4t/hm²?hereinafter referred to as N1?and 8 t/hm²?hereinafter referred to as N2?.The main findings are as follows:?1?Plant height,rice root number and root length of N1 and N2 treated with nitrogen-rich biochar in early and late paddy field were greater than those of the control?P<0.05?,which N1 treated leaf area and chlorophyll significantly higher than the control group?P<0.05?.Compared with the control,the treatment of N1 of early and late rice application increased the rice seed setting rate and rice yield?P<0.05?.It found that the treatment of N1 application significantly increased the phenotypic parameters of rice and promoted the growth of rice.The TN concentrations in roots,stems and leaves of early rice tillering stage and maturity stage were significantly higher than those in the control group?P<0.05?.The TP concentrations in stems and leaves of early and late rice mature stage were significantly higher than those in the control group?P<0.05?.?2?Under the treatment of nitrogen-rich biochar,the TC concentrations in roots,stems and leaves of early rice were significantly higher than that in the control group?P<0.05?,and the TC concentrations in stems and leaves of late rice were significantly higher than that in the control group?P<0.05?.At the same time,the dry matter weight of roots,stems and leaves of the N1 treatment group were significantly higher than those of the other groups?P<0.05?.During the tillering stage,the carbon sequestrations of roots,stems and leaves of the plants were as follows:stem>leaf>root.It can be seen that plant carbon sequestration mainly depended on rice stems.During the maturity of early and late rice,the carbon sequestrations of roots,stems,leaves and grains of N1 rice plants were significantly higher than that of other control groups?P<0.05?.The carbon sequestrations of roots,stems,leaves and grains of the plants were as follows:grain>stem>leaf>root.During the maturity period,the plant carbon sequestration mainly relied on the rice organ grain.?3?In the different growth stages of early and late paddy field,the soil SOC and MBC concentrations treated with nitrogen-rich biochar N1and N2 were generally higher than those of the control group.Compared with the control group,the<0.25 mm grade soil aggregate decreased by 6.37%in the N1 of early paddy field treatment.The MWD,GMD and DR0.25 treated in the early rice layer group increased by 6.60%,9.34%and15.55%in N1,respectively.The percentage of carbon and nitrogen concentration was mainly concentrated in large aggregates?>0.25 mm?.During the late paddy period,the Ca-SOC concentrations in the N1 treated plough layer were significantly higher than those in the control treatment.The Fe?Al?-SOC concentrations were significantly higher than those in the bottom layer,and the late paddy sloping soil residual state-SOC concentrations were significantly higher than those of early paddy field.In summary,the application increased the soil carbon concentrations and the stability of the carbon pool.The Shannon index and Simpson index of bacteria and fungi treated with N1 of morning and late paddy application were higher than those of the control group.The Shannon index and the Shannon index of fungi in the nitrogen-rich biochar N2 treatment of late paddy application were higher than those in the control group.?4?The application of nitrogen-rich biochar N1 and N2 increased the emission flux of CO₂.The whole growth period of the early and late paddy field,the application and its interaction with time significant affects CO₂ emission from paddy ecosystems throughout the growing season.The CH₄ emissions of the N1 and N2 treatment groups in early paddy were significantly lower than the control group?35.17%and 96.77%?,and the difference in late paddy was not significant.Most of the carbon emissions from paddy field were still derived from CO₂.The combined greenhouse effect of N1 and N2 treatments in early paddy field were higher than those of the control group by 70.17%and 13.79%,respectively.The late paddy increased by 33.98%and 25.35%,respectively,compared with the control group.The greenhouse effect contribution rate of CO₂ was above 90%,which was much higher than the greenhouse effect contribution rate of CH₄.