作　　者： ; ; ;

机构地区： 华南农业大学林学院

出　　处： 《生态学杂志》 2013年第6期1596-1606,共11页

摘　　要： 林火是林地上自由蔓延的火,主要有计划火烧(控制火烧)和野火2种类型。火烧的严重程度决定了火灾的效果及其影响的持续时间。火能够通过燃烧有机质和改变粘土矿物来影响土壤结构,导致土壤容重增加和持水能力降低。长期来看,火烧引起土壤有机质减少。火烧之后土壤温度和pH值的升高会促进土壤呼吸,而微生物数量的减少、根系的死亡和可分解物质的减少则减弱土壤呼吸。林火消耗了森林的枯落物层,通过氧化、挥发、灰分颗粒对流、淋溶等途径减少了森林土壤的养分含量。火灾对土壤生物有重要影响,火灾引起的高温可直接杀死土壤微生物,同时通过改变土壤的各种理化性质及林地微环境,间接影响土壤微生物生存和群落的组成。火对土壤动物的影响显著小于对土壤微生物的影响,原因是前者具有更高的灵活性来逃避火灾。中低程度火烧主要通过土壤环境变化间接影响土壤酶,而严重火烧则通过高温直接使其变性。今后应开展跨学科的森林火灾长期研究,加强对火烧后土壤动物、微生物和生态系统之间相互关系的研究,注重计划用火、火灾对土壤有机碳、土壤养分库的稳定、土壤斥水性、水土流失强度和生物多样性影响方面的研究。 Forest fire is the free spread fire in woodland ecosystems. There are two types of forest fire, i. e. , prescribed （controlled） fire and wildfire. The effects and the duration of fires depend upon the fire severity. Fires can affect soil structure through the combustion of soil organic matter and the alteration of soil clay minerals, leading to the increase of soil bulk density and the de- crease of soil water holding capacity. Over a long period of time, fires can reduce soil organic matter. After burning, the increase of soil temperature and pH can promote soil respiration, while the decrease of microbial biomass, death of roots, and decrease of decomposable materials can reduce soil respiration. Forest fires consume the forest litter layer by oxidation, volatilization, leaching, and convection of ash particles, which results in soil nutrient loss. Forest fires also have important effects on soil organisms. The high temperature of burning can directly kill soil microbes, and indirectly affect soil microbe survival and microbial community structure through changing the soil physical and chemical properties and the woodland microenvironment. The effects of fires on soil animals are less obvious-than on microbes because the soil animals have higher mobility to escape fires. Low and moderate severity fires indirectly affect soil enzymes by altering soil environment, whereas high severity fires could directly denature soil enzymes because of the extreme high temperature. In the future, the studies on forest fires should be focused on the long-term study with interdisciplinary cooperation, especially for the interrelationships among soil animals, microbes, and ecosystem responses after burning, and the effects of prescribed and wildfires on soil organic carbon, stability of soil nutrient pool, soil water repelleney, soil and wa- ter loss, and biodiversity.

关 键 词： 林火 土壤结构 土壤养分 土壤生物

领　　域： [农业科学]