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以小兴安岭湿地为研究对象,分析了不同年代排水造林的森林沼泽湿地土壤溶解性有机碳(DOC)含量变化及生物降解特征,探讨了排水造林时间对土壤DOC及无机氮(NH+4-N+NO-3-N)淋溶动态变化的影响.结果表明:1排水造林时间对土壤DOC含量变化影响显著(p<0.05).2003年(PS03)、1992年(PS92)、1985年(PS85)排水造林后的人工兴安落叶松湿地土壤DOC含量均低于未排水造林的天然兴安落叶松苔草湿地(XATC),且排水造林时间越长,土壤DOC含量越少.2在生物降解过程中,土壤DOC的变化趋势表现为初期降解速率较快,而后逐渐减慢并趋于稳定.其中周转时间为1 d的易降解DOC所占比重表现为:PS92>XATC>PS03>PS85,表明排水时间达到一定阈值后,易降解DOC部分可能会转化为难降解部分.3在淋溶过程中,随着淋溶次数的增加,淋出液中DOC含量呈现为先增加后减小的趋势,淋溶1 d后,不同年代排水造林的森林沼泽湿地土壤DOC的淋失率表现为:PS85>PS92>PS03>XATC,表明排水造林时间越长,土壤DOC淋失率越大,因此长时间的排水造林改造可能进一步影响土壤养分的贮量及其有效性.
Taking Xiaoxing’anling wetland as the research object, the changes of dissolved organic carbon (DOC) content and biodegradation characteristics in the soil of forest wetland in different years were analyzed. The effects of drainage time on DOC and inorganic nitrogen (NH 4 + -N + NO-3-N) leaching dynamics.The results showed that: 1 drainage afforestation time significantly affected the DOC content of soil (p <0.05) .In 2003 (PS03), 1992 (PS92), 1985 (PS85) The DOC content of artificial larch wetland after drainage and afforestation was lower than that of X. larch and Carex wetland (XATC) without drainage, and the longer the time of drainage and afforestation, the less DOC content in soil.2 During the process of biodegradation, The trend of soil DOC showed that the initial degradation rate was fast, then gradually slowed down and stabilized, in which the proportion of readily degradable DOC with turn-around time of 1 d was: PS92> XATC> PS03> PS85, indicating that the drainage time reached After a certain threshold, the DOC part degraded easily may transform into refractory part.3 During the leaching process, the DOC content in leachate first increases and then decreases with the increase of leaching times, After different years of drainage forest wetlands wetlands The results showed that the leaching rate of soil DOC was: PS85> PS92> PS03> XATC, indicating that the longer the time of drainage and afforestation, the greater the DOC leaching rate, so prolonged drainage afforestation could further affect soil nutrient storage and its effectiveness Sex.