草地生态系统中土壤氮素矿化影响因素的研究进展

氮素是各种植物生长和发育所需的大量营养元素之一，也是牧草从土壤吸收最多的矿质元素．土壤中的氮大部分以有机态形式存在，而植物可以直接吸收利用的是无机态氮．这些有机态氮在土壤动物和微生物的作用下。由难以被植物直接吸收利用的有机态转化为可被植物直接吸收利用的无机态的过程就是土壤氮的矿化．氮素矿化受多种因子的影响，这些因子可以归结为生物因子和非生物因子．生物因子包括：土壤动物、土壤微生物和植物种类．土壤动物可以促进土壤有机质的矿化；土壤微生物种类、结构及功能与氮的分解、矿化有密切的关系；不同的植物种类对土壤氮素的矿化作用是不相同的，一般来说。有豆科植物生长的土壤比其它种类土氮素矿化的作用大．非生物因素一般可以分为环境因子和人类活动干扰．环境因子中土壤温度和含水量对土壤氮素矿化的影响是国内外众多科学家研究的方向．尽管如此，在此方面的研究还没有取得一致意见，仍然需要进行这方面的研究，而在其他诸如：不同的土壤质地与土壤类型方面，研究报道的结论也很不一致，草地生态系统中人类活动对土壤氮素矿化的影响主要包括，不同强度的放牧，割草以及施肥、火烧强度等．非生物因子对氮素矿化的影响非常直接和明显，尤其是人类活动．本文综述了近年来影响草地生态系统土壤氮素矿化有关因素的一些进展．

Advances in study of factors affecting soil N mineralization in grassland ecosystems

The biological and non-biological factors affecting soil N availability in grassland ecosystems were reviewed in this paper. Nitrogen cycling in grassland ecosystems is one of the focuses widely concerned. Nitrogen mineralization is affected by many factors in grassland ecosystem, which can be classified into biological and non-biological ones. Biological factors include soil animals, soil microorganisms and plants. Soil animals could accelerate the organic matter to degrade. The species, structure and function of soil microorganisms correlate significantly with N degradation and mineralization. Different vegetation has different effects on soil nitrogen mineralization. The non-biological factors include environmental factors and anthropogenic disturbance, which have direct and obvious effects on N mineralization. The effects of soil temperature and moisture on N mineralization are given more attention, but many phenomena, such as the effects of soil type, soil structure and vegetation type on N mineralization still could not be explained clearly, and no general agreements were reached. Anthropogenic disturbance such as grazing, firing and fertilization influence N mineralization evidently. It is of great significance to understand the N cycling pattern and N availability in different grassland ecosystems all around the world.