摘 要 ：在两种水分条件下(W1:非淹水，W2:淹水)分4个氮处理(分别相当于氮沉降率0、1、3、5 g N·m-2·a-1)模拟了三江平原典型湿地植物湿草甸小叶章(Deyeuxia angustifolia)植株及土壤活性碳库对氮沉降的响应.结果表明：模拟氮沉降下小叶章的 生物量(总生物量、地上生物量、根生物量)均高于对照，其中根生物量的增长程度最大；根 中碳含量及分配比例均显著提高，而地上部位的碳含量则显著降低(P<0.05).氮沉降对 土壤活性碳库具有显著影响，各活性碳库含量均以5 g N·m-2·a-1处理最高，氮沉降对各活性碳库的影响程度依次为CHC(碳水化合物碳)＞LBC(易氧化有机碳)＞DOC(水 溶性有机碳)＞MBC(微生物量碳)，氮沉降与淹水条件的耦合作用有利于活性碳的释放；回归 分析表明，土壤活性碳库与小叶章相关参数间存在显著相关性.氮沉降显著提高了小叶章植 株生物量及土壤的活性碳含量.
Abstract:A simulation study was made on the responses of biomass of Deyeuxia angustifolia and soil active carbon pool in Sanjiang Plain of Northeast China to simulated nitrogen deposition. Two water conditions (W1: nonflooded, W2: flooded) and four N treatments (equivalent to 0, 1, 3, 5 g N·m-2·a-1 nitrogen deposition rate) were installed. The results showed that under effects of nitrogen deposition, the total biomass, aboveground biomass, and root biomass of D. angustifolia were higher than the control, and the increment of root biomass was the highest. Both the carbon content and its allocation proportion in D. angustifolia root increased significantly, while the carbon content in aboveground part decreased dramatically (P<0.05). Nitrogen deposition also had significant effects on soil active carbon pools, and the contents of various fractions in the carbon pool were the highest in treatment 5 g N·m-2·a-1. The responses of various fractions in soil active carbon pool to nitrogen deposition followed the sequence of carbohydrate carbon＞labile carbon＞dissolved organic carbon＞microbial biomass carbon, and the interaction between nitrogen deposition and flooded water condition facilitated the release of soil active carbon. Regression analysis indicated that there were significant correlations between soil active carbon pools and plant indices of D. angustifolia. Nitrogen deposition could enhance the biomass of D. angustifoliat and soil active carbon content.