Effects And Mechanisms Of Different Fertilizers On Methane Emission From Paddy Fields

CH₄ is an important greenhouse gas in the atmosphere second only to CO₂,and its global warming potential is roughly 25 times that of CO₂.According to statistics,the national methane emissions can reach 61.59Tg,of which about 15%comes from the paddy ecosystem.Therefore,reducing CH₄ emissions from rice fields is of great significance for mitigating the greenhouse effect.This study explored the effects of no fertilizer（CK）,conventional fertilization（CF）,organic fertilizer partial replacement of chemical fertilizers（OF）and carbon-based fertilizers（SF）on paddy field CH₄emissions,soil physical and chemical properties,and methanogen and methanotroph community structure through field trials impact.The main results are as follows:（1）In terms of the seasonal cumulative emissions of CH₄,the SF treatment is 426.31 kg·hm^-2,which is 4.70%,11.19%and 33.37%lower than that of the CK,CF and OF treatments,respectively.Through analysis,it is found that the cumulative emission of CH₄ from paddy fields has a significant positive connection with soil NH₄⁺-N,and a negative connection with soil NO₃^--N content.（2）Compared with CK,CF,OF and SF treatment significantly increased paddy yield,but there was no significant difference between each other.Throughout the rice growing season,the content of available phosphorus in the soil under different fertilization treatments gradually increased,while the content of available potassium gradually decreased.（3）The OF treatment increased the activityof Methanosarcina and Rice Cluster I in paddy soil,and inhibited the activity of aerobic methanotrophs,which caused CH₄ emissions increased in paddy soi.（4）SF treatment inhibits the activity of Methanosarcina and Rice Cluster I,and reduces CH₄emissions from paddy fields by increasing the activity of soil aerobic methanotrophs.