氮沉降对凋落叶分解前期土壤酶活性的影响

发布时间：2018-01-24 07:05

本文关键词： 氮沉降凋落物分解纤维素酶天冬酰胺酶土壤　出处：《森林与环境学报》2017年02期 　论文类型：期刊论文

【摘要】：为了解凋落叶分解前期土壤酶活性对氮沉降的响应,通过室内模拟自然氮沉降(30 kg N·hm~(-2)·a~(-1)),设置无凋落叶(bare soil,BS)、马尾松凋落叶(Pinus massoniana litter,PL)、杉木凋落叶(Cunninghamia lanceolata litter,CL)及木荷凋落叶(Schima superba litter,SL)4种处理,恒温恒湿的条件下研究不同树种(马尾松、木荷、杉木)凋落叶分解率、土壤理化性质和土壤天冬酰胺酶及纤维素酶活性动态。结果表明:模拟氮沉降232 d后,杉木凋落叶分解最快,其次是木荷凋落叶,马尾松凋落叶分解最慢。随着外源氮的累积与凋落叶分解,凋落叶全氮含量增加,C∶N减小,土壤pH值下降显著。添加硝酸铵明显提高土壤氮素有效性。外源氮的持续输入能促进土壤纤维素酶活性增加,抑制土壤天冬酰胺酶的活性。凋落叶在分解前期抑制了土壤纤维素酶活性而后期起促进作用,但凋落叶分解对土壤天冬酰胺酶活性的影响无显著规律性。因此,氮循环将改变森林土壤C∶N比,从而影响森林生态系统的物质循环和能量流动。
[Abstract]:In order to understand the response of soil enzyme activity to nitrogen deposition in the early stage of leaf litter decomposition, the natural nitrogen deposition of 30 kg N 路hm ~ (-2) 路a ~ (-1) ~ (-1) was simulated in laboratory. The leaves of Pinus massoniana litterata and Pinus massoniana litters of Pinus massoniana were set up. Cunninghamia lanceolata litterfly (Cunninghamia lanceolata litters) and Schima superba litter (Schima superba litter). The litter decomposition rate of different tree species (Pinus massoniana, Schima superba, Chinese fir) was studied under the condition of SL)4 seed treatment and constant temperature and humidity. Soil physicochemical properties and soil asparaginase and cellulase activities. The results showed that after the simulated nitrogen deposition for 232 days, the litter leaves of Chinese fir were decomposed fastest, followed by the litter leaves of Schima superba. The litter leaves of Pinus massoniana decompose most slowly. With the accumulation of exogenous nitrogen and the decomposition of litter leaves, the total nitrogen content of leaves increased and C _ (1) N decreased. The addition of ammonium nitrate significantly increased the availability of soil nitrogen, and the continuous input of exogenous nitrogen promoted the increase of soil cellulase activity. Inhibition of soil asparaginase activity. Litter leaf inhibited soil cellulase activity and promoted it in the early stage of decomposition, but litter leaf decomposition had no significant regularity on soil asparaginase activity. The nitrogen cycle will change the C: n ratio of forest soil, thus affecting the material cycle and energy flow of forest ecosystem.
【作者单位】：福建农林大学资源与环境学院;平潭综合实验区市政园林有限公司;福建省土壤环境健康与调控重点实验室;福建省环境监测中心站;
【基金】：国家自然科学基金项目(41473083)
【分类号】：S714
【正文快照】： 随着化石燃料燃烧和化肥大量使用,全球大气氮沉降日益增加,并引发一系列环境问题,如水体富营养化、土壤酸化和氮饱和,严重威胁陆地与水生生态系统安全[1-3]。森林是陆地生态系统的主体,在全球碳、氮循环中扮演着重要作用。氮沉降增加会造成森林土壤营养失衡、生产力降低等问题

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