马占相思人工林土壤有机碳的异质性

Spatial Heterogeneity of Soil Organic Carbon of Acacia mangium Plantation in Heshan,Guangdong,China

以鹤山站马占相思林土壤为研究对象,对相关土壤、生物指标进行了分析。对马占相思人工林土壤的地统计学研究结果表明:马占相思人工林土壤有机碳和全氮在空间分布上存在着较为显著的空间自相关性,即自相关部分的空间异质性占主导地位,分别占总空间异质性程度的81.3%和84.2%。土壤有机碳分布的空间特征与土壤全氮分布空间特征具有较一致的空间异质性;林木根生物量的分布特征未表现出与土壤有机碳分布的一致空间异质性,这说明根生物量的分布特征在表层土0-15 cm有机碳的空间分布差异上不是主导因子。林地碳、氮不但存在传统统计学上的线性相关,它们也具有景观层次上的空间自相关,指数模型的拟合表明,在7.62 m小尺度范围内,土壤有机碳的空间自相关性存在,在6.60 m尺度范围内,全氮的空间自相关性存在。

Geostatistical techniques were used to quantify the scale and degree of soil heterogeneity of Acacia mangium plantation forest land in south China. Samples for analysis of soil organic carbon and total nitrogen content were taken on an aligned grid. The contents of soil organic carbon and total nitrogen were measured, and root biomass was estimated. Kriged maps of C and N content showed a strong spatial autocorrelation. This observation agreed with traditional statistics analysis showing a significant linear correlation between C and N. The best fitting from exponential model showed that soil organic carbon and total nitrogen have high degree of spatial heterogeneity at the scales of 7.62 m and 6. 60 m, respectively, such that 81.3% and 84. 2% of the total spatial heterogeneity originated from the spatial autocorrelation. The correlation between soil organic carbon and root biomass was not shown that root biomass performed as the dominated factor in accordance with its role of source of soil organic carbon.