不同林龄木荷人工林土壤团聚体稳定性及粒径分布特征

Stability and Particle Size Distribution Characteristics of Soil Aggregates in Schima superba Plantations of Different Stand Ages

  • 摘要: 为研究不同林龄阶段木荷人工林土壤团聚体稳定性及粒径分布特征,以福建省顺昌国有林场5个林龄(10、15、27、55、64 a)木荷人工林0—20、20—40、40—60 cm土层的土壤为研究对象,探究木荷人工林土壤团聚体稳定性、分布特征及其林龄效应。结果表明:(1)不同林龄木荷人工林土壤团聚体以大团聚体(>0.25 mm)为主,大团聚体比例皆达90%以上,其中>2 mm的团聚体结构占比最大,微团聚体(<0.25 mm)比例不足10%,说明不同林龄木荷人工林的土壤团聚体都具有强团聚性的特点。(2)与干筛法相比,湿筛法得到的土壤水稳定性团聚体中>2 mm团聚体的占比明显减少,0.25~2 mm占比增加;在0—40 cm土层中,64 a木荷人工林土壤团聚体水稳定性占比和水稳性特征值显著高于其它林龄,表明木荷人工林在过熟林阶段的土壤透气性、透水性最好。(3)不同粒径土壤团聚体随林龄、土层深度及林龄×土层深度交互作用呈现出不同的变化趋势,在土壤机械稳定性团聚体中林龄的影响最明显;而在水稳定性团聚体中,林龄、土层、林龄×土层交互作用均对土壤团聚体的平均质量直径(MWD)和几何平均直径(GWD)产生显著影响(P<0.05)。

     

    Abstract: In order to study the particle size distribution characteristics of soil aggregates in five Schima superba plantations of different age stages, soil samples from the 0—20 cm, 20—40 cm and 40—60 cm layers of 10 a, 15 a, 27 a, 55 a and 64 a were collected for analysis at Shunchang State Owned Forest Farm, Fujian Province.The aim was to investigate the impact of plantation age on the stability and distribution characteristics of soil aggregates in Schima superba plantations.The findings revealed that:(1) large aggregates(> 0.25 mm) were predominant in the soil aggregates of various age Schima superba plantations, accounting for over 90% of the total, with the >2 mm aggregates being the most abundant, while micro-aggregates(< 0.25 mm) made up less than 10%.This suggests that soil aggregates in different age Schima superba plantations exhibited strong agglomeration characteristics.(2) Wet screening resulted in a significant decrease in the proportion of aggregates(>2 mm) and an increase in the 0.25~2 mm aggregates comPAred to dry screening.In the 0—40 cm soil layer, the water stability weight ratio and characteristic values of 64 a aggregates were notably higher than those of other stand ages, indicating superior soil permeability and water retention in the overmature large-diameter wood forest.(3) Soil aggregates of different sizes exhibited varying trends with changes in stand age and soil layers, with their interactions.In soil mechanical stability aggregates, the influence of stand age was the most significant.In water-stable aggregates, the MWD and GWD of soil aggregates were significantly influenced by stand age, soil layer, and their interaction(P < 0.05).

     

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