外源氮输入对小叶章湿地土壤微生物活性的影响

Effects of Exogenous N Input on Soil Microbial Activity in Deyeuxia angustifolia Marshes

选择三江平原沼泽湿地典型草甸植被小叶章(Deyeuxia angustifolia),在水分、温度等环境因素均一的前提下,分别以NH4NO3水溶液的形式均匀撒入0,6,12,24g/(m2.a)(以N元素量计),进行了室外盆栽实验。结果表明,氮输入后,土壤MBC、MBN、BR、qCO2、SIR季节变化明显;在植物不同生长阶段,土壤基础呼吸总体趋势均是随时间的推移而逐渐减弱,且与氮输入量间的关系不同,说明土壤基础呼吸与植物的生长阶段密切相关;不同施氮水平的土壤MBC浓度随氮输入量增加呈波动变化,氮输入量与土壤MBN、BR、qCO2、SIR之间均存在线性正相关关系,即他们随氮输入量增加而逐渐增大,说明氮输入促进了土壤MBN、BR、qCO2、SIR的增大。

Under the uniformity of moisture,temperature and other environmental factors status,dissolved NH4NO3 were supplied on the seedlings of D.angustifolia in field potted experiment （calculated as N element,the simulated enhanced N supplies were equivalent to 0（N0）,6（N6）,12（N12） and 24（N24） g/（m^2·a） in the freshwater marshes of Sanjiang Plain.The results indicated that the seasonal variation of the MBC,MBN,BR,qCO2,SIR was obvious among the different nitrogen treatments.The overall trends of soil basal respiration in different growth stages of D.angustifolia were weakened with the passage of time,moreover,the relationships between the nitrogen application and the variation of BR were different that explain BR closely related to the growth phase of plants.The variation of the MBC presented fluctuation along with the increasing amount of nitrogen input.There were relationships between N inputs and MBN,BR,qCO2,SIR.Their augmented trends along with the increasing amount of nitrogen input illustrated that N inputs promoted the augmentation of MBN,BR,qCO2,SIR.