北京地区栓皮栎和油松人工林土壤团聚体稳定性及有机碳特征

Soil aggregate stability and soil organic carbon characteristics in Quercus variabilis and Pinus tabulaeformis plantations in Beijing area

通过野外调查与室内分析,研究了北京地区栓皮栎和油松人工林土壤水稳性团聚体稳定性及有机碳分布特征.结果表明:在两种人工林内,大团聚体含量均随土层加深呈减少的趋势.其中,油松人工林中大团聚体(>0.25mm)含量占总团聚体的71%～77%;栓皮栎人工林中大团聚体含量(51%～58%)与微团聚体(≤0.25mm)含量(42%～49%)差异不明显.油松人工林土壤平均质量直径和几何平均直径均显著高于栓皮栎人工林,分形维数D值小于栓皮栎人工林.在两种林分中,土壤各粒级团聚体有机碳含量均随土壤层次的加深呈现逐渐降低的趋势.油松人工林中水稳性大团聚体的有机碳对土壤有机碳的贡献率为58%～83%,高于栓皮栎人工林水稳性大团聚体有机碳对土壤有机碳的贡献率(49%～66%).油松人工林比栓皮栎人工林更利于土壤水稳性团聚体的稳定和土壤有机碳的保护.

Based on the field survey and laboratory analysis, this paper studied the soil aggregate stability and soil organic carbon characteristics in Quercus vadabilis and Pinus tabulaeformis planta- tions in Beijing area. In the two plantations, the contents of soil macro-aggregates decreased with soil depth. In P. tabulaeformis plantation, soil macro-aggregates （〉0.25 mm） occupied the major- ity, accounting for 71% - 77% of the total; whereas in Q. variabilis plantation, no significant difference was observed in the contents of soil macro-aggregates and micro-aggregates （ ≤0.25 mm）, which accounted for 51% -58% and 42% -49%, respectively. Both the mean mass diameter and the geometrical mean mass diameter of the soil aggregates in P. tabulaeformis plantation were significantly higher than those in Q. variabilis plantation, and the fractal dimension （D） of the soil water-stable aggregates in P. tabulaeformis plantation was lower than that in Q. varia- bills plantation, suggesting that P. tabulaeformis plantation was more favorable for the soil aggregate stability than Q. variabilis plantation. Also in the two plantations, the organic carbon content in soil water-stable aggregates decreased with soil depth. The organic carbon content in soil macro-aggregates was significantly higher in P. tabulaeformis plantation （58% -83% ） than in Q. variabilis plantation （49%-66%）. It to the soil organic was suggested that in Beijing area, P. tabulaeformis plantation was more beneficial carbon protection, as compared with Q. variabilis plantation.