东祁连山不同干扰生境草地土壤养分时空变化特征

为探究东祁连山不同干扰高寒草地土壤养分及其生态化学计量学特征时空变化特征规律。研究了2017年8月在东祁连山不同干扰高寒草地土壤养分含量及其生态计量学特征,以及与2003年和2011年在相同地点、相同研究方法对该地区的土壤理化性质进行比较。结果表明:(1)在同一干扰生境不同土层下,土壤pH、电导率、含水量、土壤全量和速效养分均随着土层深度增加而逐渐减小,变化各异;在同一土层不同干扰生境下土壤养分间变化差异各不相同。(2)不同干扰生境土壤C/N为7.64~18.21,与我国陆地土壤平均值(10~12)基本接近,土壤C/P和N/P分别为109.16~144.79和7.52~15.65,远高于中国陆地土壤的C/P平均值52.7和N/P平均值3.9。(3)主成分分析结果表明,土壤理化性质(pH、电导率、含水量、全磷、全钾、速效磷、有机质、有机碳和速效氮)和土壤生态化学计量比(C/N、C/P和N/P)可以敏感的反映出不同干扰对草地土壤质量影响状况。土壤质量综合评价可知,不同干扰生境下草地土壤质量水平差异较大,多年生草地土壤质量较高,围栏外草地质量最差,在0-20,20-40cm土层中,均表现为多年生围栏内一年生围栏外。(4)与2003年和2011年相比较,4种不同干扰生境高寒草地土壤pH和含水量,总体呈上升的趋势,土壤有机质、全氮和全磷含量则呈现出明显下降趋势。综上,放牧干扰、人为种植对东祁连山4种干扰生境草地土壤养分含量有很大影响,为此应对该地区草地的利用和保护给予足够的重视,合理利用和科学管理草地。

Temporal and Spatial Variation Characteristics of Grassland Soil Nutrients in Different Disturbed Habitats of East Qilian Mountains

In order to explore the temporal and spatial variation characteristics of soil nutrients and their ecological stoichiometry in different disturbed alpine grasslands in East Qilian Mountains. The soil nutrient content and its ecometrics characteristics of different disturbed alpine grasslands in Eastern Qilian Mountains in August 2017 were studied. Compared with the same sites in 2003 and 2011, the same research methods were used to compare the soil physical and chemical properties in this area. Results showed that:(1) Soil pH value, electroconductibility, water content, soil total amount and available nutrient all decreased with the depth of soil and varied with different soil layers in the same disturbed habitat. (2) The soil C/N ranged from 7.64 to 18.21 in different disturbed habitats, which was basically close to the average value (10~12) of land soils in China. The soil C/P and N/P that ranged from 109.16 to 144.79 and 7.52 to 15.65 respectively, was much higher than the average C/P of 52.7 and N/P of 3.9 in China. (3) The principal component analysis showed that the physical and chemical properties of soil (pH, electrical conductivity, water content, total phosphorus, total potassium, available phosphorus, organic matter, organic carbon and available nitrogen) and ecological stoichiometry ratio (C/N, C/P and N/P) in the soil could sensitively reflected the different disturbance on grassland soil quality. The comprehensive evaluation of soil quality showed that the difference of grassland soil quality under different disturbed habitat vary greatly, the perennial grassland soil quality is higher, and the grass quality outside the fence is the worst. At 0-20 cm and 20- 40 cm soil layer, soil quality ranged as perennial cultivated grassland> inside the fence grassland> Annual cultivated grassland> outside the fence grassland. (4) Compared with 2003 and 2011, the pH value and water content of four different disturbed alpine grasslands showed an overall upward trend, while the content of soil organic matter, total nitrogen and total phosphorus showed a significant downward trend. In summary, grazing disturbance and artificial planting had a great impact on the soil nutrient content of four disturbed grasslands in the eastern Qilian Mountains. Therefore, adequate attention should be paid to the utilization and conservation of the grassland in this area, and the grasslands should be rationally utilized and scientifically managed.