神农架森林土壤养分及生态化学计量特征

Nutrient and Ecological Stoichiometry Characteristics of Forest Soils in Shennongjia

  • 摘要: 以神农架山地森林土壤为例, 研究有机碳(SOC)、全氮(TN)、全磷(TP)、全钾(TK)等土壤养分含量及其生态化学计量特征沿海拔梯度(1300~3100 m)的变化, 阐明其对地形、植被和土壤因子的响应。结果表明: SOC、TN、TP和TK含量分别在14.32~35.39 g/kg、2.20~5.62 g/kg、0.28~0.46 g/kg、20.75~22.96 g/kg。SOC、TN、TP含量随海拔升高呈增加趋势, TK含量则呈相反变化趋势。C/N、C/K、N/K、P/K均随海拔升高呈线性增加, 最大值出现在海拔3100 m处。山地不同垂直植被带土壤养分含量及其生态化学计量比存在显著差异, 山地灌丛草甸土壤SOC和TN含量较高, TP和TK含量较低, 且该植被带的生态化学计量比显著高于其他植被带。相关分析表明, 海拔与C、N、P、K之间生态化学计量比呈正相关, C/K、N/K与海拔之间相关性显著。相较于北坡, 南坡土壤生态化学计量比受海拔影响更显著。

     

    Abstract: The soil nutrient contents of organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK) and their ecological stoichiometric characteristics were studied along an altitude gradient (1300~3100 m) to elucidate their responses to topography, vegetation and soil factors in a forest soil in the Shennongjia mountains. The results showed that the contents of SOC, TN, TP and TK ranged from 14.32~35.39 g/kg, 2.20~5.62 g/kg, 0.28~0.46 g/kg and 20.75~22.96 g/kg, respectively. The contents of SOC, TN and TP showed an increasing trend with elevation, while TK showed an opposite trend. C/N, C/K, N/K and P/K all increased linearly with elevation, and the maximum value was found at 3100 m above sea level. Soil nutrient contents and their ecological stoichiometric ratios were significantly different in different vertical vegetation zones in the mountainous area, with higher SOC and TN contents and lower TP and TK contents in mountainous scrub meadows, and the ecological stoichiometric ratios in this vegetation zone were significantly higher than those in other vegetation zones. Correlation analysis showed that the ecological stoichiometric ratios between elevation and C, N, P and K were positively correlated, and the correlations between C/K and N/K and elevation were significant. Compared with the northern slope, the soil ecological stoichiometry ratios on the southern slope were more significantly affected by elevation.

     

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