中温-暖温带表土碳氮磷生态化学计量特征的空间变异性——以河北省为例

解析区域土壤碳氮磷元素的生态化学计量特征的空间分异格局有助于土壤养分的综合管理与利用。运用传统统计学和地统计学分析方法,以河北省为例分析了中温-暖温带表土(0—30cm)碳氮磷元素的生态化学计量特征的空间变异性及影响因素。结果显示:(1)土壤有机碳(SOC)、全氮(TSN)、全磷(TSP)其摩尔比率的变异系数均介于0.1—1之间,表明其在空间上存在中等程度的变异性。此外,C∶N的变异系数较小,表明C∶N较稳定。(2)表土TSP和C∶N具有小范围、强烈的空间自相关性,SOC、TSN、C∶P和N∶P具有较大范围、中等程度的空间自相关性,结构性因素是土壤碳氮磷含量及其摩尔比率空间变异的主要影响因素。从空间分布规律来看,表土碳氮磷含量及其摩尔比率均没有呈现明显的递增或递减的变化规律,SOC、TSN、C∶P和N∶P具有相同的空间分布趋势,高值区主要分布在冀北地区,分布面积较小,低值区分布范围较广;C∶N的高值区零星分布在冀北地区,TSP的高值区和低值区呈现斑块状分布。(3)土壤C∶N、C∶P和N∶P受到土壤理化性状、土地利用方式、人类扰动、气候及地形等因素的调控。此外,不同气候带的C∶N、C∶P和N∶P也存在一定的差异,研究区土壤C∶N与高寒带较接近,同时与其他气候带没有显著的差异;C∶P和N∶P与温带沙漠区较接近,与其余气候带存在显著的差异性,说明不同气候带之间的C∶N较C∶P和N∶P稳定。

Spatial variation of ecological stoichiometry characteristics of topsoil carbon, nitrogen and phosphorus in Hebei Province, China

The study on ecological stoichiometric characteristics of elements in soils is important to revealing mechanisms of the circulation and balance of soil carbon, nitrogen, phosphorus and other elements, and the knowledge of spatial variance of the ecological stoichiometric characteristcs of soil carbon, nitrogen and phosphorus is conducive to soil nutrient management. Spatial distributions of stoichiometric characteristcs of soil C, N and P in the topsoil (0-30cm) and influence factors were systematically analyzed in total Hebei Province. Based on the soil survey data in Hebei Province, the traditional statistics, geostatistics and ordinary kriging interpolation method were used to analyze the spatial variation characteristics of C:N:P and its influence factors. The results showed that (1) The variation coefficients of SOC, TSN, TSP and their molar ratios were between 0.1-1, which indicated that there existed spatial variability with a moderate degree. In addition, the variation coefficient of C:N was smaller, which indicated C:N was more stable than N:P and C:P. (2) Topsoil TSP and C: N has a small range and strong spatial autocorrelation, and SOC, TSN, C: P and N: P has a large range and a moderate degree of spatial autocorrelation. Structural factors were main factors of influencing spatial variation of soil organic carbon, nitrogen, phosphorus content and their molar ratio. From the spatial distribution, soil carbon, nitrogen and phosphorus content and its molar ratio did not show obvious increasing or decreasing trend. SOC, TSN, C:P and N:P had the same spatial distribution trend. High value region mainly distributed in the north of Hebei and the distribution area was small. The low value distributed widely in Hebei Province. The high value of TSP distributed in North Hebei, and the high value and low value of C:N showed patch-shape distribution. (3) C:N, C:P and N:P were affected by soil physical and chemical properties, land use patterns, human disturbance, climate and topography so on. In addition, there were some differences between N:P, C:P and C:N in different climate zones. C:N of study region was close to that of and the alpine zone, and there was no significant difference from other climatic zones. C:P and N:P of study region were close to the temperate zone, and there existed significant differences from other climate zones, which indicated that C:N was more stable than C:P and N:P in different climate zones.