鲁中南药乡小流域林地土壤有机碳空间分布特征

Spatial distribution of soil organic carbon in the forestland of the Yaoxiang small watershed in central and southern Shandong Province

土壤有机碳库是全球碳循环和气候变化研究的核心内容,以鲁中南山区药乡小流域林地土壤为研究对象,应用地统计学和GIS技术,研究林地土壤有机碳的空间异质性分布特征。结果表明：1）土壤有机碳和全氮、全磷质量分数随土壤层深度增加而减小,土壤有机碳质量分数在0~10和10~30 cm土层之间差异极显著;全氮和全磷质量分数在0~10和10~30 cm土层之间差异显著。2）0~10 cm土层的有机碳质量分数与全氮质量分数、海拔呈极显著正相关,与全磷质量分数呈显著正相关;在10~30 cm土层有机碳质量分数与全氮质量分数、海拔呈显著正相关。3）土壤有机碳质量分数的半方差函数模型属于高斯模型,0~10 cm土层有机碳质量分数具有强烈的架构化区域模式;10~30 cm土层有机碳质量分数表现为中等强度的空间自相关性。4）土壤有机碳质量分数是流域的东部和西北部较高、中南部较低;有机碳质量分数分布由东部和西北部向中南部递减,基本与药乡小流域DEM趋势一致。5）0~10 cm土层的土壤有机碳质量分数分形维数较小,土壤有机碳空间格局较简单;10~30 cm土层的有机碳质量分数分形维数较大,土壤有机碳空间格局较为复杂。不同方位的土壤有机碳质量分数分形维数表明,东-西方向是药乡小流域林地土壤有机碳分布的优势格局。

The spatial heterogeneity of soil organic carbon（ SOC） levels is important in researches of both global carbon- nitrogen cycle and climate change. By employing geostatistics methods and GIS technology,we studied the spatially heterogeneous distribution of SOC in the Yaoxiang small watershed in the hilly area of central and southern Shandong Province. Results showed that： 1） SOC,total nitrogen and total phosphorus contents showed a trend of declining with the increase of soil depth,and there was an extremely significant difference in SOC content between 0- 10 cm and 10- 30 cm soil layers,and significant differences in total nitrogen and total phosphorus contents were found between 0- 10 cm and10- 30 cm soil layers. 2） SOC content in 0- 10 cm soil layer had an extremely significantly positive correlation with total nitrogen content and elevation,and had a significantly positive correlation with total phosphorus content; SOC content in 10- 30 cm soil layer had a significantly positive correlation with total nitrogen and elevation. 3） Semivariogram model of SOC content belongs to the Gaussian model,and SOCcontent in 0- 10 cm soil layer had a strong regional pattern,and that in 10- 30 cm soil layer showed a moderate spatial correlation. 4） SOC content was higher in the eastern and northwestern parts and lower in the central and southern parts of the small watershed; the distribution of SOC diminished gradually from the eastern and northwestern parts to central and southern parts,which was basically consistent with the trend of DEM in the Yaoxiang small watershed. 5） Fractal dimension of SOC content in 0- 10 cm soil layer was smaller than that in 10- 30 cm soil layer,and the spatial pattern of SOC was relatively simple;in contrast,the spatial pattern of SOC in 10- 30 cm soil layer was more complex. The fractal dimensions of SOC content in different directions showed that the east-west（ E-W） direction was the advantageous pattern of SOC distribution in the Yaoxiang small watershed.