Effects Of Of Varieties, Fertilization And Cultivation Mode On Methane And Nitrous Oxide Fluxes In Rice Paddy In Fuzhou Plain

Taken the Fuzhou plain as the study area, methane and nitrous oxide emission fluxes were determined in situ by static chamber method in paddy fields of Fuzhou plains. Treatment variables included rice varieties, sulphur and iron fertilization and cultivation mode, each treatment with three replications. The observations of iron fertilizer addition treatment during the early rice growth stage were from the middle of April to the middle of July in2011and the observations during the late rice growth stage were from the early of August to the late of November in2011. The effects of the different treatments on the greenhouse gas emission and rice production were investigated basing on the analyzing of observed data in the Fuzhou plain.The main results showed:(1) In the whole rice growth period, comparing with the conventional rice varieties, methane flux from super rice reduced by about4%, but nitrous oxide flux increased nearly133%.(2) Calculated on a CO2-equivalent basis, conventional rice variety plots emitted2264.50kgCO2hm-2and super rice plots emitted1977.04kgCO2hm"2, suggesting super rice plots emitting about13%less than those of conventional rice variety plots. Super rice plots had higher rice production compared with the conventional rice varieties plots.(3) Average methane emissions followed the order of PY<SC<ZB<JC and the averaged nitrous oxide emissions were in the order of SC<JC<PY<ZB. The thousand-grain weight were in the order of JC<SC<ZB<PY and single cluster rice production were in the order of SC<PY<JC<ZB.(4) The comprehensive greenhouse effect followed the order of PY<SC<ZB<JC. The comprehensive greenhouse effect of JC plots were nearly24%higher than those of SC plots, and ZB plots were nearly22%higher than those of PY.(5) In the whole rice growth period, comparison with the control treatment, methane flux from sulpher fertilizer addition plots reduced about25%, but nitrous oxide flux increased nearly49%.(6) Control plots emitted2264.5kg CO2hm-2while sulpher fertilizer amended plots emitted1728.47kg C02hm-2suggesting that sulpher fertilizer addition reduced GHG emission by24%over those of control plots. Seed setting rate in sulpher fertilizer amended plots increased by4%, and thousand-grain weight and single bundle production increased by14%and15%, respectively.(7) Comparison with Fe-0plots, the average methane flux from Fe-2, Fe-4and Fe-8plots reduced by26.37%,43.41%and48.87%, and the averaged nitrous oxide flux reduced by20.92%,25.27%and66.36%in early paddy field, respectively. Comparison with Fe-0plots, the averaged methane flux from Fe-2, Fe-4, Fe-8plots reduced by44.26%,63.93%and66.12%, and the averaged nitrous oxide flux reduced by6.49%,43.58%and15.95%in late paddy fields, respectively.(8) The comprehensive greenhouse effect followed the order of Fe-0>Fe-2> Fe-4> Fe-8in early paddy fields, similar trend in the late paddy fields. The yields were in the order of Fe-0<Fe-2<Fe-4<Fe-8both in early and late paddy fields.