上海崇明岛不同施肥条件下的稻田温室气体排放格局

在上海崇明岛稻田里设置3个水平(当地正常水平,该水平的70％和50％)的施肥处理进行试验,利用静态箱/气象色谱监测体系,对3种温室气体(CO2、CH4以及N2O)进行动态监测,分析温室气体的排放量和变化规律,探讨土壤温湿度以及有机质对土壤温室气体排放通量的影响,寻求在不影响产量的条件下,减少温室气体排放的施肥措施.研究表明,施肥水平显著影响CH4和N2O的排放通量,CO2排放量与水稻生长特性有密切关系；施肥水平的提高没有促进土壤有机质的积累.在70％施肥水平下,样地的干物质积累及实际产量与100％施肥水平未有显著差异,且土壤温室气体排放量显著降低.本文结论可对农田生态系统固碳及降低农田温室气体的排放提供科学依据.

Greenhouse Gases Emission Pattern in Paddy Fields under Different Fertilizer Conditions in Chongming Island,Shanghai

In order to clarify the effects of soil humidity and organic substances on GHGs emission flux,and obtain the fertilizer methodology to reduce GHGs emission without decreasing the output of the farm field.In this study,statistic chamber/GS system was used to monitor the dynamic of GHGs emissions and the discharging and changing rules of the GHGs flux (including CO₂,CH₄ and N₂O) were analyzed as well under three different fertilizer management of paddy fields (local normal fertilizer management,70% and 50% of normal fertilizer management) in Chonming Island,Shanghai.The results showed that CH₄,N₂O emission flux were significantly affected by fertilizer application during rice season and CO₂ emission flux was changed with the growth characteristic of rice.Higher fertilizer condition was not able to enhance the soil organic carbon (SOC) accumulation.The accumulation of dry matter and real yield of rice were not significantly different between 70% fertilizer and 100% fertilizer condition (P> 0.05).However,the GHGs flux decreased significantly under the 70% fertilizer condition.These results could provide scientific basis for the methodologies of carbon sequestration and decrease of GHGs flux in farmland ecosystem.