模拟氮沉降对温带森林土壤酶活性的影响

发布时间：2018-06-14 14:51

本文选题：氮添加 + 酶活性　；参考：《生态学报》2017年06期

【摘要】：森林土壤酶作为土壤中最活跃组分,能影响生态系统的物质循环过程,其活性能快速反映氮沉降对土壤环境的变化。以北京地带性植被辽东栎林为研究对象,利用模拟氮沉降方法,原位设计低氮(50 kg N hm~(-2)a~(-1),N50)、高氮(150 kg N hm~(-2)a~(-1),N150)两个施氮水平,每个施氮水平设置Na NO_3、(NH_4)_2SO_4、NH4NO_33个不同的施氮类型,另设置空白对照(0 kg N hm~(-2)a~(-1),N0)。从时间格局上研究不同氮素化学形态和剂量对温带森林土壤6种酶(脲酶、酸性磷酸酶、碱性磷酸酶、β-葡萄糖苷酶、多酚氧化酶和过氧化氢酶)活性的影响。结果表明:在氮形态和水平的交互作用下,NH4NO3-N处理的脲酶活性显著高出NO~-_3-N处理的24.20%(N50),NH~+_4-N处理对酸性磷酸酶活性的影响显著高出NO~-_3-N处理的13.82%(N150);在NH~+_4-N和NH_4NO_3-N处理中,N50水平下的脲酶活性分别高出N0处理的38.90%和24.20%,差异显著。对无氮形态和水平交互作用的酶活性分析得出,不同的施氮水平,对碱性磷酸酶和多酚氧化酶的酶活性有显著促进作用,碱性磷酸酶活性在N50和N150处理下分别比N0高20.2%和11.5%,N50和N150处理对多酚氧化酶活性的促进作用分别比N0处理高64.3%和41.8%,差异显著(P0.05);NH~+_4-N处理对β-葡萄糖苷酶活性具有显著促进作用(P0.05),不同的施氮形态,对碱性磷酸酶、多酚氧化酶和过氧化氢酶的酶活性无显著影响。6种酶活性均呈现了显著的时间变化,氮添加对森林土壤酶活性的时间分异规律没有显著影响。此外,土壤微生物量碳、硝态氮和铵态氮含量与酶活性具有显著相关性(P0.05)。以上结果表明,氮添加通过改变森林土壤的环境因子,影响了土壤中的水解酶和氧化酶活性,进而改变了土壤有机碳库和养分循环。
[Abstract]:Forest soil enzyme, as the most active component in soil, can affect the material circulation process of ecosystem, and its activity can quickly reflect the change of soil environment caused by nitrogen deposition. In this paper, the Quercus liaotungensis forest in the zonal vegetation of Beijing was used as the research object. By means of the method of simulated nitrogen deposition, we designed in situ two nitrogen application levels of low N ~ (50) N ~ (50) kg N ~ (50) ~ (-1) ~ (-1) N ~ (+) ~ (150) N ~ + ~ (150) N ~ + ~ (150) ~ (150) N ~ (+) ~ + ~ (150) N fertilizer levels. In addition, a blank control of 0 kg N 路hm ~ (-1) ~ (-1) was set up. The effects of different nitrogen chemical forms and doses on the activities of six enzymes (urease, acid phosphatase, alkaline phosphatase, 尾 -glucosidase, polyphenol oxidase and catalase) in temperate forest soil were studied. The results showed that the urease activity of NH _ 4NO _ 3-N treatment was significantly higher than that of NO-T _ 3-N treatment under the interaction of nitrogen form and level, and the effect of NH ~ + _ 4-N treatment on acid phosphatase activity was significantly higher than that of NO-3-N treatment (13.82N ~ 150), and under NH ~ 4-N and NH _ 4NO _ 3-N treatment, the effect of NH ~ 4-N and NH _ 4NO _ 3-N treatment on acid phosphatase activity was significantly higher than that on NH ~ 4-N and NH _ 4NO _ 3-N treatment. The urease activity of N0 was significantly higher than that of N0 treatment by 38.90% and 24.20%, respectively. The results of enzyme activity analysis on the interaction of nitrogen free form and level showed that different nitrogen levels promoted the enzyme activities of alkaline phosphatase and polyphenol oxidase significantly. The activities of alkaline phosphatase in N50 and N150 treatments were 20.2% and 11.5% higher than that of N0, respectively. The effects of N50 and N150 treatments on polyphenol oxidase activity were 64.3% and 41.8% higher than those of N0 treatment, respectively. The difference was significant (P 0.05 NH ~ 4-N treatment) on 尾 -glucosidase activity. Promoting effect of P0.05, different forms of nitrogen application, The enzyme activities of alkaline phosphatase, polyphenol oxidase and catalase showed no significant change in time, but nitrogen addition had no significant effect on the temporal differentiation of enzyme activity in forest soil. In addition, soil microbial biomass carbon, nitrate nitrogen and ammonium nitrogen contents were significantly correlated with enzyme activity. The results showed that nitrogen addition affected the activities of hydrolase and oxidase by changing the environmental factors of forest soil, and then changed the soil organic carbon pool and nutrient cycle.
【作者单位】：北京林业大学环境科学与工程学院;
【基金】：中央高校基本科研业务费专项资金(2016JX02) 国家自然科学基金(41373069)
【分类号】：S714

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