The Effect Of Straw Application On Soil Carbon Pool,Methane And Nitrous Oxide Emissions In The Paddy Fields Of Fuzhou

Straw application has been attracting the attention of scholars both at home and abroad, however, we still know litter about the impact of straw application on soil carbon pool and greenhouse gas emissions. In this study, we studied the effects of straw application on emissions of CH4and N2O in the rice field of Fuzhou plain, which was a typical subtropical humid monsoon climate region. This experiment consists of straw application and the control treatments, and each treatment replicated for three times. We measured the emissions of CH4and N2O by static chambers-gas chromatography methods, and also studied the soil organic carbon pool. The main results are as follows:(1) Soil organic carbon in the rice field was significantly influenced by straw application and soil layers. Straw application increased the organic carbon concentration. Soil organic carbon of both treatments decreased with soil depth increment.(2) Soil properties were significantly affected by straw application and rice field type. In early rice field, the averaged concentrations of light fraction organic carbon (LFOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and easily oxidizable carbon (EOC) in0-40cm soil layers with straw application were0.37g·kg-1,129.07mg·kg-1,108.96mg·kg-1and0.53g·kg-1, respectively. The averaged concentrations of LFOC, DOC, MBC and EOC in0～40cm soil layers of the control were0.34g·kg-1,111.68mg·kg-1,47.66mg·kg-1and0.56g·kg-1, respectively. In late rice field, the average concentrations of LFOC, DOC, MBC and EOC in0-40cm soil layers with straw application were0.73g·kg-1,74.66mg·kg-1,122.64mg·kg-1and0.64g·kg-1, respectively. The average concentrations of LFOC, DOC, MBC and EOC in0～40cm soil layers of the control were0.64g·kg-1,60.58mg·kg-1,112.40mg·kg-1and0.58g·kg-1, respectively. On the whole, straw application decreased the active fractions of soil organic carbon in both the early and late rice field.(3) In the whole growth period of early rice, the averaged CH4and N2O flux were decreased by27.21%and42.79%due to straw application in comparison with the control.However, in the whole growth period of late rice, the averaged CH4and N2O emission flux were increased by346.72%and105.97%due to straw application in comparison with the control.