Lian Zi-Wen, DU Hu, Gu Jun-Kun, Zeng Fu-Ping, Peng Wan-Xia, Yin Li-Chu, Long Qing-Zhi, Liu Kun-Ping, Sun Rui, Tan Wei-Ning
Key Laboratory of Agro-ecological Processes in Subtropical Region, Public Technology Center, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences/Guangxi Key Laboratory of Karst Ecological Processes and Services, Huanjiang 547100, Guang-xi, China.
Ying Yong Sheng Tai Xue Bao. 2023 Apr;34(4):955-961. doi: 10.13287/j.1001-9332.202304.008.
Understanding the spatial heterogeneity of soil available medium- and micro-elements in karst area can provide a valuable theoretical guideline for soil nutrient management of karst ecosystem. We collected soil samples at a soil depth of 0-10 cm using grid sampling (20 m×20 m) in a 25 hm (500 m×500 m) dynamic monitoring plot. We further analyzed the spatial variability of soil medium- and micro-elements and their drivers, with classic statistics analysis and geo-statistics analysis. The results showed that the average contents of exchangeable Ca and Mg and available Fe, Mn, Cu, Zn, and B were 7870, 1490, 30.24, 149.12, 1.77, 13.54, and 0.65 mg·kg, respectively. The coefficient of variation of the nutrients ranged from 34.5% to 68.8%, showing a medium degree of their spatial variation. The coefficient of determination of the best-fit semi-variogram models of each nutrient was higher than 0.90, except for available Zn (0.78), indicating a strong predictive power for the spatial variation of the nutrients. The nugget coefficients for all the nutrients were less than 50%, showing a moderate spatial correlation, and the structural factors played a pivotal role. The spatially autocorrelated variation was within the range of 60.3-485.1 m, among which available Zn showed the lowest range and the deepest fragmentation degree. The spatial distribution of exchangeable Ca, Mg, and available B were consistent, with contents in the depression being significantly lower than that in other habitats. The contents of available Fe, Mn, and Cu declined with the increases of altitude and were significantly lower on the hilltop than in other habitats. The spatial variation of soil medium- and micro-elements was closely related to topographic factors in karst forest. Elevation, slope, soil thickness, and rock exposure rate were the primary drivers of spatial variation of soil elements and need to be considered in soil nutrient management of karst forestlands.
了解喀斯特地区土壤有效中微量元素的空间异质性可为喀斯特生态系统的土壤养分管理提供有价值的理论指导。我们在一个25公顷（500米×500米）的动态监测样地中采用网格采样（20米×20米）方法采集了0-10厘米深度的土壤样本。我们进一步运用经典统计分析和地统计学分析方法，分析了土壤中微量元素的空间变异性及其驱动因素。结果表明，交换性钙、镁以及有效铁、锰、铜、锌和硼的平均含量分别为7870、1490、30.24、149.12、1.77、13.54和0.65毫克·千克。养分的变异系数在34.5%至68.8%之间，表明其空间变异程度为中等。除有效锌（0.78）外，各养分最佳拟合半变异函数模型的决定系数均高于0.90，表明对养分空间变异具有较强的预测能力。所有养分的块金系数均小于50%，表明具有中等空间相关性，且结构因素起关键作用。空间自相关变异范围在60.3-485.1米之间，其中有效锌的范围最低，破碎程度最深。交换性钙、镁和有效硼的空间分布一致，洼地中的含量显著低于其他生境。有效铁、锰和铜的含量随海拔升高而下降，山顶的含量显著低于其他生境。喀斯特森林土壤中微量元素的空间变异与地形因素密切相关。海拔、坡度、土壤厚度和岩石出露率是土壤元素空间变异的主要驱动因素，在喀斯特林地土壤养分管理中需要加以考虑。
