高原鼠兔不同干扰强度对高山嵩草草甸土壤有机碳和全氮含量及其贮量的影响

Effect of disturbance of plateau pika on soil organic carbon and nitrogen content and storage of Kobresia pygmaea meadow

利用高原鼠兔(Ochotona curzoniae)有效洞口数密度划分高原鼠兔干扰强度的方法,研究不同高原鼠兔干扰强度对高山嵩草(Kobresia pygmaea)草甸土壤有机碳和全氮含量及其贮量的影响,以期阐明高原鼠兔对土壤养分供给能力的影响.结果表明,随高原鼠兔干扰强度增加,高山嵩草草甸土壤有机碳和全氮含量以及其贮量均表现为先增加后降低的变化趋势,在干扰强度Ⅱ时最大(对应的有效洞口数密度为224个/hm2)(P<0.01).高原鼠兔干扰条件下,0-10 cm土层的有机碳和全氮含量显著大于10-20 cm土层的有机碳和全氮含量(P<0.01),而有机碳和全氮贮量在0-10cm和10-20 cm土层间差异不显著.因此,从高山嵩草草甸土壤养分调控角度看,适量的高原鼠兔干扰能够提高高山嵩草草甸土壤有机碳和全氮的固持潜力.

This study aimed to determine the effect of different disturbances of plateau pika on soil organic carbon and nitrogen content and their storage in the Kobresia pygmaea meadow. A field survey was conducted in August, 2013 to investigate the contents and storage of soil organic carbon and total nitrogen of K. pygmaea meadow at different disturbance degrees of plateau pika. The disturbance of plateau pika was divided into four degrees （I, II, III and IV） by the active burrow entrance density of plateau pika. Three 25 m×25 m plots were designed at each disturbance degree, each plot consisted of five sample sites. The soil samples of each sample sites were collected in 0-10 cm and 10-20 cm depths, then removed plants roots, stone and other impurities. The soil samples were then air dried, crushed and sieved through a 2 mm screen, to be conserved for analyzing. The results showed that soil organic carbon and nitrogen content and their storage first increased and then decreased with the increase of the disturbance degree, peaking at II with 224 active burrow entrances per ha. Under the disturbance of plateau pika, soil organic carbon and nitrogen content at 0-10 cm layer was bigger than that at 10-20 cm layer, but their storage was not significantly different between the two layers in the K. pygmaea meadow. Therefore reasonable disturbance degree of plateau pika would increase the soil organic carbon and nitrogen seauestration ootential in K. vvemaea meadow.