摘要
自由放牧草地羊粪归还作用在空间上往往表现出一定梯度分布格局,是影响自由放牧草地土壤与植被空间分布与演替动态的重要因素。为深入认识荒漠草原放牧对草地的影响格局与作用机制,以宁夏盐池荒漠草原围栏放牧草地为研究对象,按自然形成的地表羊粪量梯度,设置了6个梯度序列控制样地（1.41~1 581.68g/m2）,模拟自然条件下不同放牧强度。重点分析不同放牧强度下草地植物多样性与土壤环境因子之间的关系。结果表明,随着放牧强度的增加,1）植物群落中优势种白草的地位逐渐被苦豆子取代;白草重要值由2.07减小到0.19,苦豆子重要值由0增加到1.25。2）植物群落物种多样性指数从0.64增加到2.26,丰富度指数从0.35增加到1.86,均匀度指数没有一定的变化规律。3）0~5cm土层,土壤全氮、速效氮和水分对植物群落物种多样性变化的影响较大,其中,土壤全氮是显著性影响因子;5~10cm土层,土壤速效氮和有机碳对植物群落多样性变化的影响较大,其中,土壤速效氮是显著性影响因子。初步研究结论认为：放牧扰动下,表层土壤中氮素的增加是荒漠草原植物多样性变化的主导因子之一,这种结果的产生很可能与家畜排泄物的归还作用有关。明确氮的来源与去向,可能是下一步深入认识有关羊粪归还作用机制的主要任务。
The effect of sheep dung return presenting a certain pattern of gradient distribution in spatial was a very important factor which effected the spatial distribution of soil and vegetation and dynamics of succession in meadow with free grazing conditions. In order to develop a deeper understanding on the effect of grazing to the pattern of influencing and the mechanism of action of meadow in desert steppe, we conducted a research that the grass plant diversity and the relationship between plant diversity and soil environmental factors were stud- ied by setting up six gradient sequence sample （1.41--1 581.68 g/m2） according to the natural surface of sheep dung quantity gradient in Ningxia desert steppe ecosystem. The results showed that plant community presented a trend which the dominance status of Penniseluru cenlrasialicuru was substituted by Sophora alopecuroides ： the importance value of cenlrasialicuru decreased from 2.07 to 0.19, the importance value of alopecuroides in- creased from 0 to 1.25. The plant diversity index of margalef increased from 0.64 to 2.26, Shannon-Wiener in- creased from 0.35 to 1.86 respectively but the index of Pielou was not necessarily change rule with the increase of grazing intensity. The main soil environment factors affecting the plant diversity were soil total nitrogen as the significant one, moisture content and available nitrogen at 0--5 cm soil layer, soil organic carbon and nitro- gen as the significant one at 5--10 cm soil layer respectively. Preliminary research conclusions considered the one most important factor affecting the plant diversity was the increasing of soil nitrogen and this result may be related to nutrient return of grazing livestock excreta. Confirming where the nitrogen comes from and goes to may be the primary mission in further recognizing of the mechanism of action about sheep dung return in the grassland ecosystems of desert steppe.
出处
《草业学报》
CSCD
北大核心
2013年第5期27-36,共10页
Acta Prataculturae Sinica
基金
国家973计划前期研究专项(2012CB723206)
国家科技支撑计划课题(2011BAC07B03)资助
关键词
放牧扰动
荒漠草原
植物多样性
主导因子
grazing disturbance
desert steppe
plant diversity
dominant factor
