Abstract:Paddy fields are an important source of methane (CH4) and nitrous oxide (N2O) emissions.In this study,an in-situ rice field experiment was carried out to investigate the influence of different organic manures on rice yield and greenhouse gas emissions in a typical double-cropping rice field in the Pearl River Delta region.The treatments included no fertilizer (CK),chemical fertilizer (CF),stack organic fertilizer (SOF),rapidly composted organic fertilizer (COF),fresh organic fertilizer (FOF),and sterilized organic fertilizer (STOF).The five fertilization treatments were applied equally at nitrogen level.The static chamber-gas chromatography was used to measure greenhouse gas fluxes in this study.The results are as follows:1) The order of rice yields was STOF>FOF>COF>CF>SOF>CK.Compared with chemical fertilizer treatment,the rice yields under STOF,FOF,and COF increased by 19.3%,17.1%,and 15.5% (P<0.05),respectively,and their economic benefits increased by 41.2%,69.4%,and 24.2%,respectively.2) The total emissions of CH4 in the double-cropping rice seasons were in the order of COF>FOF>SOF>STOF>CF>CK.Compared with chemical fertilizer treatments,the total emissions of CH4 increased by 333.5%,261.3%,154.1%,and 128.6% under the treatments of COF,FOF,SOF,and STOF,respectively (P<0.05).3) During the rice growing period,the CH4 was still the main greenhouse gas in this region since the N2O emissions of various fertilizer treatments were at a low level.4) Compared with chemical fertilizer,the four organic fertilizers significantly increased the global warming potential and greenhouse gas intensity of rice fields.From the perspective of the whole life cycle,the COF has shorter composting time and less greenhouse gas emission,and thus is more economical and environment friendly.