摘要
采用室内模拟试验,在好气和淹水2个土壤水分条件下,研究了外源氮输入对沼泽湿地土壤有机碳矿化和土壤可溶性有机碳(DOC)含量的影响.结果表明,好气条件下,净氮输入量为1 mg.g-1(N1)的氮处理水平对土壤有机碳矿化和DOC含量的影响不显著,而净氮输入量为2和5 mg.g-1(N2、N3)时,土壤DOC含量显著增加,分别比对照(250.62 mg.kg-1)增加了187.22%和203.25%,并显著促进了土壤有机碳的矿化;淹水条件下,外源氮输入则抑制了土壤有机碳的矿化,N1、N2、N3处理下土壤DOC含量分别比对照(642.52 mg.kg-1)降低了88.34%、82.69%、80.04%;不同水分条件下,土壤DOC含量与有机碳的累积矿化量均呈显著正相关关系(R2分别为0.939、0.843),由外源氮输入引起土壤DOC含量的变化可能是导致土壤有机碳矿化差异的主要原因之一.研究结果还表明,伴随着沼泽湿地积水消退和外源氮输入的增多,将会加快湿地土壤有机碳的矿化和土壤DOC的淋失,造成湿地土壤有机碳的大量损失.
By laboratory incubation experiment, under aerobic and submerged soil moisture conditions, we investigated the mineralization of soil organic carbon （SOC） and contents of dissolved organic carbon （ DOC ） with different nitrogen inputs in a freshwater marsh soil. The results showed that under aerobic condition, there were no significant effects on the mineralization of SOC and contents of DOC as the net nitrogen input was 1 mg.g^-1 （ N1 ）, however, they were significantly higher than control and N1 treatments when nitrogen input increased to 2 and 5 mg.g^-1 （N2,N3）, and the amount of DOC was respectively 187.22% and 203.25% higher than control （250.62 mg.g^-1 ）. Under submerged condition, all N treatments restrained the mineralization of SOC, and the content of DOC was respectively 88.34 % （N1）, 82.69 % （N2） and 80.04% （N3） lower than control （642.52 mg.g^-1）. There were significant positive correlations between the contents of DOC and the amounts of cumulative C by mineralization（ R2 was 0.939 and 0.843,respectively）,which suggested that the changes of DOC affected by N input might be one of the important reasons that arose the differences of SOC mineralization. The results also indicate that as the waterlogged environment disappeared in wetland, the supply of exogenous nitrogen might bring large loss of SOC through enhancing the mineralization of SOC and leaching of DOC.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2008年第12期3525-3530,共6页
Environmental Science
基金
国家自然科学基金项目(40771189)
中国科学院知识创新工程重要方向项目(KZCX2-YW-309)
中国科学院“东北振兴”项目(DBZX-2-024)
关键词
沼泽湿地
氮输入
土壤有机碳
矿化
DOC
marsh
nitrogen input
soil organic carbon
mineralization
DOC
