Effect Of Combined Application With Organic And Inorganic Fertilizers On Rice Growth And Greenhouse Gas Emission From Double-cropping Paddy Fields

It is conducive to evaluate the environmental effect and economic benefit as well as provide scientific basis for combined application of organic and inorganic fertilizers, when investigating the effect of different fertilizers on greenhouse gas emission(CC2、CH4、N2O) and rice growth. In this paper, a field plot experiment was conducted to investigate the effect of different fertilization treatments on CO2, CH4and N2O emission flux from double-cropping paddy field by using the static chamber-gas chromatograph technique during rice growth period in2012. The difference of greenhouse gas emission flux among fertilization treatments, corresponding influencing factors together with effect of fertilization treatments on comprehensive greenhouse effect in paddy soil were discussed. And the primary results were as follows:1、 The law of CO2emission flux variation seasonally among different fertilization treatments was identical, principally influenced by rice growth and temperature. CO2emission flux in paddy soil was of significantly positive correlation with atmospheric temperature, and the relation between accumulated CO2emission and rice biomass exhibited the same trend. In contrast to chemical fertilizer treatment, treatments with combined application of organic and inorganic fertilizers could obviously promote the CO2emission in paddy fields, but had no significant difference. Fertilization level affected CO2emission by affecting rice biomass accumulation.2、Methane emitted mostly in paddy soil, which was under the durative water logging condition, accounting for88.0%of the total methane discharge. It indicated that field moisture content was a significant factor regulating methane emission. Treatments with combined application of organic and inorganic fertilizers could increase methane discharge, and methane emission amount ranked the highest level, up to449.6kg/hm2per year, increased by207.3%compared to chemical fertilizer treatment. The difference was extremely significant between fresh pig manure application treatment and others, but not significant among DF, ZYF and CF treatments. The fresh pig manure application could significantly increased methane emission in paddy fields, while the DF treatment and ZYF treatment were not remarkably increase methane emission.3、The N2O emission mainly existed in drying period of paddy soil, accounting for89.26%of total emission. The N2O emission amount among treatments was in the following order:DF> CF> ZF> ZYF> WN> WF. The promotion of N2O emission was largely depend on organic fertilizer variety.4、Paddy field eco-system played an important role in CO2sink during rice growth period. CH4was the main greenhouse gas in paddy fields, more than96%of the total net emission of greenhouse gases, while N2O emission was little. The integrated warming potential among different treatments were ZF> CF> ZYF> WF> DF> WN. In contrast to CF, the rice yield in treatments with organic and inorganic fertilizer application increased, and GWP(Global warming potential) of unit yield were ZF> CF=ZYF> DF> WF> WN. The pig manure composting, biogas slurry and mineral fertilizer could increase crop yield as well as the fixed greenhouse gas amount in paddy field eco-system correspondingly, possessing immense potential to slow down greenhouse gas emission.