Ouyang Zi-Wen, Peng Wan-Xia, Song Tong-Qing, Zeng Fu-Ping, Wang Ke-Lin, Guan Xin, Wu Hai-Yong
Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Ying Yong Sheng Tai Xue Bao. 2009 Jun;20(6):1329-36.
By using geostatistic methods, this paper studied the spatial variation and distribution of soil organic matter as well as its ecological processes and related mechanisms in four typical disturbed areas (cropland, man-made forest, secondary forest, and primary forest) of karst peak cluster depressions in northwest Guangxi of China. Eighty soil samples (0-20 cm) were collected from an aligned grid of 10 m x 10 m for the analysis of soil organic matter. The soil organic matter content increased significantly (P < 0.05) with the decrease of disturbance and the vegetation succession from crop to man-made forest to secondary forest to primary forest. Soil organic matter content had good spatial autocorrelation in all of the four typical disturbed areas, but its spatial heterogeneity differed. Gaussian model fitted best to the semivariance functions of soil organic matter content in the study areas except secondary forest area where exponential model fitted well. In cropland area, the spatial autocorrelation of soil organic matter was at medium level, with the C0/(C0 + C) being 26.5%; while in the other three areas, the spatial autocorrelation was at high level, with the C0/(C0 + C) being 9.0%-22.6%. The range and scale of the spatial autocorrelation of soil organic matter in cropland and man-made forest areas were larger than those in the other two areas, possibly due to the strong human disturbance and the homogeneity of low energy. The range of the spatial autocorrelation of soil organic matter in primary forest area was large due to the high vegetation coverage, while that in secondary forest area was the lowest due to the diverse vegetation communities and their uneven distribution. The low fractal value (D) of semivariance functions of soil organic matter in man-made forest and primary forest areas suggested that a strong spatial dependence existed, while the high D in cropland and secondary forest areas suggested a great random variance of spatial distribution of soil organic matter occurred. The spatial pattern of soil organic matter presented a unimodal distribution in cropland and man-made forest areas, a concave distribution in secondary forest area, and a gibbous distribution in primary forest area. To reduce human disturbance would be helpful to the soil quality improvement, rapid vegetation restoration, and ecological reconstruction of karst degenerative ecosystems.
运用地统计学方法，研究了桂西北喀斯特峰丛洼地4种典型干扰区域（农田、人工林、次生林和原生林）土壤有机质的空间变异与分布及其生态过程和相关机制。从10 m×10 m的规则网格中采集了80个土壤样本（0 - 20 cm）用于分析土壤有机质。随着干扰程度的降低以及植被从农作物到人工林、再到次生林、最后到原生林的演替，土壤有机质含量显著增加（P < 0.05）。在所有4种典型干扰区域中，土壤有机质含量均具有良好的空间自相关性，但其空间异质性有所不同。除次生林区域指数模型拟合较好外，高斯模型对研究区域土壤有机质含量的半方差函数拟合效果最佳。在农田区域，土壤有机质的空间自相关性处于中等水平，C0/(C0 + C)为26.5%；而在其他3个区域，空间自相关性处于高水平，C0/(C0 + C)为9.0% - 22.6%。农田和人工林区域土壤有机质空间自相关的范围和尺度大于其他两个区域，可能是由于强烈的人为干扰和低能量的同质性。原生林区域土壤有机质空间自相关范围较大是因为植被覆盖率高，而次生林区域由于植被群落多样且分布不均，其空间自相关范围最小。人工林和原生林区域土壤有机质半方差函数的分形值（D）较低，表明存在较强的空间依赖性，而农田和次生林区域的D值较高，表明土壤有机质空间分布存在较大的随机变异。土壤有机质的空间格局在农田和人工林区域呈单峰分布，在次生林区域呈凹形分布，在原生林区域呈凸形分布。减少人为干扰将有助于喀斯特退化生态系统的土壤质量改善、植被快速恢复和生态重建。
