色季拉山急尖长苞冷杉林不同坡向土壤养分及肥力研究

以色季拉山不同坡向急尖长苞冷杉(Abies georgei var.smithii)天然林为研究对象,采用单因素方差、化学计量比及内梅罗指数等方法对不同坡向0—100 cm土壤的pH和7种养分含量及肥力状况进行研究,以期为色季拉山急尖长苞冷杉的经营管理提供理论依据。结果表明:(1)色季拉山急尖长苞冷杉林土壤pH7,为酸性。0—100 cm土层中除土壤全钾含量外,其他各养分含量及变异系数的均值均表现为:阳坡阴坡,且均属于中等变异程度。除全磷、全钾含量较低外,其他指标均处于"中等"及以上水平。(2)土壤有机质、全氮、碱解氮随土层的增加而降低,总体上表层与深层差异显著(P0.05),其他土层之间差异不显著(P0.05);其他养分随土层变化规律不一致,各土层之间差异不显著(P0.05)。(3)阳坡各土壤化学计量比总体上表现为随土壤深度增加而降低,阴坡呈波动性变化,除C∶N外,阳坡C∶P、C∶K、N∶P、N∶K、P∶K均小于阴坡。(4)阴坡的土壤肥力指数(1.44)大于阳坡(1.32),不同坡向土壤肥力均属于"中等"水平。坡向通过影响多种因素使土壤理化性质具有一定差异性,阴坡的土壤养分含量及肥力状况优于阳坡,全钾是第一限制因子,全磷是第二限制因子。

Soil nutrient and fertility of different slope directions in the Abies georgei var. smithii forest in Sejila Mountain

Aiming to provide a theoretical basis for the manager of Sejila Mountain, we studied the natural Abies georgei var. smithii forest from different slope directions. The pH, 7 nutrients content, and fertility status in different slope directions from 0 to 100 cm soil were measured by one-way variance, stoichiometric ratio and, Nemero index. The results showed that (1) the soil pH of the Abies georgei var. smithii forest was less than 7. Except the soil total potassium content, the mean values of other nutrient contents and coefficient of variation of 0-100 cm soil layer were all expressed as sunny slopes < Shady slope. All were moderate variation. Except for the lower content of total phosphorus and total potassium, other indicators were at medium level and above. (2) The soil organic matter, total nitrogen, and available nitrogen decreased with the increase of soil layer, and the difference between surface layer and deep layer was significant (P<0.05). There was not consistent variation in other nutrients with the deepening of soil layer, and the difference between the soil layers was not significant (P>0.05). (3) The soil stoichiometric ratios of the sunny slopes generally decreased as the soil depth increased, while the shady slopes fluctuated. Except C:N, C:P, C:K, N:P, N:K, P:K in the sunny slopes were less than those in the shady slope. (4) The soil fertility index of the shady slope (1.44) was higher than that of the sunny slope (1.32). The slope direction had certain differences in the physical and chemical properties of the soil by affecting various factors. The soil nutrient content and fertility status of the shady slope were better than those of the sunny slope. The total potassium was the first limiting factor, and the total phosphorus was the second limiting factor.