氮输入对三江湿地小叶章不同生长阶段土壤产生CH_4能力的影响

在小叶章(Deyeuxia angustifolia)不同生长阶段,用室内鲜土培养法对土壤CH4的产生能力进行了研究.结果表明,氮输入后,植物各生长阶段的土壤CH4产生率均随时间的推移发生了明显的波动.从生长季(6月7日～8月24日)CH4产生率均值来看,不同氮输入水平对土壤CH4产生起促进作用;不同氮输入水平对植物不同生长阶段CH4产生率影响明显.第一(6月7日～7月2日)、第二(7月2日～7月20日)阶段适量的氮输入(6g.m-2)对CH4产生起促进作用,但过量氮输入(12g.m-2)会对CH4产生起抑制作用;而第三(7月20日～8月7日)、第四(8月7日～8月24日)阶段不同氮输入均对CH4产生起促进作用;氮输入后,土壤微生物量碳(MBC)、土壤微生物量氮(MBN)、土壤基础呼吸(BR)、土壤代谢熵(qCO2)、土壤诱导呼吸(SIR)、铵态氮(NH4+-N)、硝态氮(NO3--N)和植物地上生物量与土壤CH4产生的动态关系存在差异.土壤CH4产生与qCO2呈显著正相关(p0.01),与土壤MBN、TOC和地上生物量呈显著正相关(p0.05).

Effects of exogenous nitrogen on methane production from Deyeuxia angustifolia marsh in different plant growth phases

CH4 production by D. angustifolia.over time was studied using indoor fresh soil cultivation under flooded soil conditions. The results indicated that the CH4 production rate showed significant volatility after nitrogen input at each growth phase. From the perspective of the mean CH4 production rate of the growing season (June 7~August 24), nitrogen input promoted CH4 production. The effect of different nitrogen input level on the CH4 production rate was obvious at different growth stages. In the first and second stages, moderate (6 g·m-2) nitrogen input promoted CH4 production, but excessive (12 g·m-2) nitrogen input suppressed CH4 production. However, nitrogen input always promoted CH4 production at the third and fourth stage. After nitrogen input, there were differences in dynamic relationships between soil microbial biomass C and N (MBC, MBN), soil basic respiration (BR), soil metabolic quotient (qCO2), soil induced respiration (SIR), ammonium nitrogen (NH+4-N), nitrate nitrogen (NO-3-N), plant biomass and CH4 production. Through correlative analysis, CH4 production was highly significantly related to qCO2 (p < 0.01), and significantly related to MBN,TOC and plant biomass (p<0.05).