子午岭林区植被自然恢复下土壤剖面团聚体特征研究

Study of the Character of Soil Aggregates under Vegetation Restoration in Ziwu Mountain

研究了子午岭林区七种植被类型土壤>0.25 mm水稳性团聚体含量、团聚体破坏率和水稳性团聚体分形维数随植被恢复的变化规律以及这3个指标随土壤有机碳含量增加的变化规律。结果表明:植被恢复对>0.25 mm水稳性团聚体含量、团聚体破坏率和水稳性团聚体分形维数的影响可以达到70 cm土层;除白羊草群落外,0-70 cm土层上>0.25 mm水稳性团聚体含量随植被恢复逐渐提高,团聚体破坏率和水稳性团聚体分形维数随植被恢复逐渐减小,土壤结构随植被恢复逐渐改善。>0.25 mm水稳性团聚体含量、团聚体破坏率和水稳性团聚体分形维数与土壤有机碳之间呈极显著对数相关关系(p=0.01,n=32),当有机碳含量低于18.1 mg/g时,>0.25 mm水稳性团聚体含量随有机碳含量提高而明显提高、团聚体破坏率和水稳性团聚体分形维数则随有机碳含量提高而明显降低,即土壤结构稳定性明显提高;当有土壤机碳含量高于18.1 mg/g,>0.25 mm水稳性团聚体含量、团聚体破坏率和水稳性团聚体分形维数渐趋稳定,即在白羊草、虎榛子、山杨和辽东栎阶段的0-5 cm土层土壤结构达到稳定状态。

In this paper,the change law of 0.25 mm water stable aggregates,aggregates destruction rate and water stable aggregates fractal dimension under different vegetation restoration period and the correlation of the three indices with SOC content were studied in Ziwu mountain.The result showed that these three indices of 0-70 cm soil layer could be effected by vegetation restoration;the content of 0.25 mm water stable aggregates increasing and the aggregate destruction rate and water stable aggregates fractal dimension decreasing and the soil structure improving with the vegetation restoration course in the 0-70 cm soil layer except the Bothriochloa ischcemum community;the relationship of these three indices and the SOC content was highly significant logarithm,when the SOC content was less than 18.1 mg/g,the content of 0.25 mm water stable aggregates increasing and the aggregates destruction rate and water stable aggregates fractal dimension decreasing significantly with the SOC content increasing,while the three indices didn＇t change significantly,it was to say that the soil structure improved significantly with the SOC content increasing when the SOC content was lower than 18.1 mg/g,the soil structure reached stable state in 0-5 cm soil layer of Bothriochloa ischcemum,Ostryopsis davidiana,Populus davidiana and Quercus wutaishanica community.