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近年来,大气氮沉降日益增加,已对森林生态系统产生了不可忽视的影响,而土壤酶活性反映了土壤肥力及土壤环境质量,因而可以用来评价氮沉降对森林土壤造成的影响。关于氮沉降对森林生态系统酶活性的影响已开展了一系列的研究,然而尚缺少系统总结。文中从森林土壤酶种类和林分类型角度总结了氮沉降对土壤酶活性的影响,并从氮沉降水平、氮种类形态、氮沉降与环境的交互作用等方面探讨了土壤酶活性对氮沉降的响应机制,提出未来研究热点是氮沉降对不同类型的森林土壤酶影响、不同森林类型土壤酶的氮沉降临界值、氮沉降对土壤酶活性影响的长期定位研究以及氮沉降与CO2浓度、温度、降雨、磷添加的交互作用对土壤酶活性影响,以期为未来森林土壤管理提供参考。 相似文献
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森林土壤碳氮过程研究现状和展望 总被引:6,自引:0,他引:6
土壤是碳和氮的重要贮存库,土壤碳氮转化是陆地上最为重要的生态系统过程之一。森林土壤中碳、氮过程是森林生态系统中物质循环与能量交换的关键。森林凋落物的分解、森林土壤碳氮的矿化是森林土壤最主要的碳氮过程。在微生物作用下,土壤与大气交换含碳氮物质,则是土壤碳氮过程的直接反应,也是影响尹土壤碳氮过程和土壤碳氮库动态的主要方面。然而。从大尺度上探讨森林植被恢复过程中土壤碳氮过程的分异机理,研究典型植物群落土壤碳氮过程特征及探索森林土壤碳氮过程与植被的互动机制及关键植物种君l对土壤碳氮过程的影响,研究土壤碳氮过程有关的土壤微生物和土壤酶及其与全球变化的关系等内容还未见报道,认为这些内容将是未来的研究重点。同时,随着科学技术的发展,各种新的技术如3S技术和电子午专感器技术等将会很快应用于森林土壤碳氮过程的研究。 相似文献
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氮沉降可能改变森林土壤CO_2通量,已有研究结果对氮沉降作用的方向和强度上具有很大的不确定性。通过整合已有模拟氮沉降的野外监测数据,评估了氮沉降对中国森林土壤CO_2通量的影响。结果表明,氮沉降平均降低了中国土壤CO_2通量的8.7%,且这种影响对次生林和人工林影响较大,而对原始林影响较小。同时,氮沉降对土壤CO_2通量的影响对阔叶林、针叶林和针阔混交林均无显著影响,但显著降低了竹林土壤CO_2通量的36%。施加100 kg N·hm~(-2)·a~(-1)时才会对森林土壤CO_2通量造成显著降低,且施加硝酸铵的降低大于尿素。氮沉降的这种影响主要是由于过多的氮抑制了土壤微生物活性造成的。 相似文献
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森林土壤有机碳(SOC)是全球碳循环的重要组成部分,然而,多样的森林类型和不同森林经营措施的干扰,使得森林土壤碳库维持机制以及碳固存过程的研究和森林土壤碳库的估算存在较大的变异。作为主要的森林经营措施之一,采伐对森林土壤碳储量以及碳过程均产生直接或间接地影响。为深刻理解森林土壤碳库对于采伐干扰的响应,本文综述了近十几年来不同采伐方式下森林土壤碳储量及其主要碳排放过程——土壤呼吸的研究现状,综合分析了采伐方式、森林类型、采伐剩余物管理以及微生物因子等对土壤碳库的影响及其不确定性,并在此基础上阐述了研究中尚未解决的主要问题:1)生物因子作为CO2产生的主体,在应对干扰时结构、功能的变化直接影响着土壤碳排放以及碳固定,但它们具体作用机制以及过程并不清楚,需展开进一步的调查;2)不同森林采伐方式对不同地区和不同类型森林土壤的影响的复杂性,亟须在进一步加强实验研究的基础上,发展森林土壤碳循环的过程或机理模型,为森林生态系统完整的碳循环过程表达及碳计量提供技术支撑,以期为我国森林经营以及碳汇等方面研究提供参考。 相似文献
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氮沉降对土壤呼吸影响研究进展 总被引:1,自引:0,他引:1
土壤呼吸是全球碳循环的重要组成部分, 土壤呼吸动态变化直接制约全球碳收支状况。近几十年来, 全球氮沉降的增加对土壤呼吸产生了深刻影响。文中从土壤呼吸的组成及影响因素入手, 综述了土壤呼吸对氮沉降响应的3种结果, 即促进、抑制和无影响; 从光合作用、凋落物分解、微生物及细根方面阐述了氮沉降影响土壤呼吸的机理, 指出未来该领域的研究方向。 相似文献
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G.W.W. Wamelink H.F. van Dobben J.P. Mol-Dijkstra E.P.A.G. Schouwenberg J. Kros W. de Vries F. Berendse 《Forest Ecology and Management》2009
Global warming and loss of biodiversity are among the most prominent environmental issues of our time. Large sums are spent to reduce their causes, the emission of CO2 and nitrogen compounds. However, the results of such measures are potentially conflicting, as the reduction of nitrogen deposition may hamper carbon sequestration and thus increase global warming. Moreover, it is uncertain whether a lower nitrogen deposition will lead to a higher biodiversity. We applied a dynamic soil model, a vegetation dynamic model and a biodiversity regression model to investigate the effect of nitrogen deposition reduction on the carbon sequestration and plant species diversity. The soil and vegetation models simulate the carbon sequestration as a result of nitrogen deposition and they provide the biodiversity model with information on the soil conditions groundwater table, pH and nitrogen availability. The plant diversity index resulting from the biodiversity model is based on the occurrence of ‘red list’ species for the tree soil conditions. Based on the model runs we forecast that a gradual decrease in nitrogen deposition from 40 to 10 kg N ha−1 y−1 in the next 25 years will cause a drop in the net carbon sequestration of forest in The Netherlands to 27% of the present amount, while biodiversity remains constant in forest, but may increase in heathland and grassland. 相似文献
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Nitrogen deposition imposes important impact on the function and the stability of forest carbon sequestration.This paper reviewed the research advances in the increasing response of forest carbon sequestration to nitiogen deposition, described the application prospects of stable carbon isotope technique in the research field.And finally this paper pointed out that,on the condition that nitrogen deposition rises,on the allocation of forest photosynthetic products and the change in soil carbon turnover rate are the two hotspots in the future carbon cycling research. 相似文献
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G.W.W. Wamelink H.J.J. Wieggers G.J. Reinds J. Kros J.P. Mol-Dijkstra M. van Oijen W. de Vries 《Forest Ecology and Management》2009
Changes in the Earth's atmosphere are expected to influence the growth, and therefore, carbon accumulation of European forests. We identify three major changes: (1) a rise in carbon dioxide concentration, (2) climate change, resulting in higher temperatures and changes in precipitation and (3) a decrease in nitrogen deposition. We adjusted and applied the hydrological model Watbal, the soil model SMART2 and the vegetation model SUMO2 to asses the effect of expected changes in the period 1990 up to 2070 on the carbon accumulation in trees and soils of 166 European forest plots. The models were parameterized using measured soil and vegetation parameters and site-specific changes in temperature, precipitation and nitrogen deposition. The carbon dioxide concentration was assumed to rise uniformly across Europe. The results were compared to a reference scenario consisting of a constant CO2 concentration and deposition scenario. The temperature and precipitation scenario was a repetition of the period between 1960 and 1990. All scenarios were compared to the reference scenario for biomass growth and carbon sequestration for both the soil and the trees. 相似文献