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对NH2Cl、KNO3和NH4NO33种氮肥设置低、中、高3个施氮水平,施加于兴安落叶松林(Larix gmelinii)样地。用常规的微生物计数及酶测定法分析了模拟大气氮沉降增加对兴安落叶松腐殖质微生物及酶活性的影响。结果表明施加NH4Cl、KNO3和NH4NO33种氮肥下,细菌数量随施氮水平的增加而显著提高;中氮水平l的NH4C和KNO3分别使放线菌数量提高;中氮水平的KNO3和NH4NO3使真菌数量增加。施加3种氮肥下,脲酶活性随着施氮水平的增加而提高;施加NH4Cl促进过氧化氢酶活性,但随氮水平提高而促进作用降低。高氮水平的KNO3和中氮水平的NH4NO3使过氧化氢酶活性提高;施加3种氮肥的实验结果均表明,低水平的氮肥可使蔗糖酶活性提高,而高水平的氮肥使蔗糖酶活性降低。
Three nitrogen fertilizers, low, medium and high, were applied to 33 nitrogenous fertilizers of NH2Cl, KNO3 and NH4NO and applied to Larix gmelinii plots. The effect of simulated atmospheric deposition of nitrogen on the humus microorganisms and enzyme activities of Larix gmelinii was analyzed by conventional microbial counts and enzyme assays. The results showed that with the application of NH4Cl, KNO3 and NH4NO33 kinds of nitrogen fertilizer, the number of bacteria increased significantly with the increase of nitrogen application rate; NH4C and KNO3 with medium nitrogen level increased the numbers of actinomycetes respectively; while those with medium nitrogen levels of KNO3 and NH4NO3 increased the number of fungi increase. Under the three nitrogen fertilizers, the urease activity increased with the increase of nitrogen application rate. NH4Cl promoted the catalase activity, but decreased with the increase of nitrogen level. High levels of KNO3 and medium levels of NH4NO3 increased the activities of catalase. The results of applying three nitrogen fertilizers showed that sucrosease activity increased with low levels of nitrogen fertilizer, while sucrase activity was decreased with high levels of nitrogen fertilizer .