不同杉木林经营模式土壤颗粒的分形特征

Fractal characteristics of soil particle size in different management patterns of Chinese fir forests

为了揭示不同杉木林经营模式的土壤结构演变规律,应用分形模型,对不同杉木林经营模式下土壤颗粒的分形维数及其与理化性质的相关性进行研究。结果表明,不同杉木林经营模式0-20 cm和20-40 cm土层的土壤颗粒分形维数值由大到小均为人工林1>人工林2>老龄林>萌芽林>天然林,这说明2种近自然杉木林经营模式(萌芽林与老龄林)比传统栽杉模式(人工林1与人工林2)更有利于改善土壤结构,但仍不如天然次生常绿阔叶林。0-20 cm和20-40 cm土层的土壤颗粒分形维数均与0.25-0.05 mm粒径土壤微团聚体含量呈极显著负相关,与0.05-0.01 mm、0.005-0.001 mm及小于0.001 mm粒径土壤微团聚体含量呈极显著正相关;20-40 cm土层的土壤颗粒分形维数与全N含量呈极显著正相关,与其它理化指标的相关性均不显著。

In order to reveal the soil structure evolution in different management patterns of Chinese fir forests,the soil fractal dimensions in different management patterns of Chinese fir forests were analyzed by fractal model,and the correlativity between fractal dimensions of soil particles and soil physical-chemical properties in different management patterns of Chinese fir forests was studied.The results showed as follows.Of different management patterns of Chinese fir forests,the fractal dimension values of soil particles in the 0-20 cm and 20-40 cm soil layers were in the following order from large to small,plantation 1 ＞ plantation 2 ＞ old aged forest ＞ sprout forest ＞ natural forest.It proved that the two nearly natural management patterns of Chinese fir （sprout forest and old aged forest） were more favorable for improvement of soil structure than the conventional plantation patterns （plantation 1 and plantation 2）,but not as good as the natural secondary broad-leaved evergreen forest.In the 0-20 cm and 20-40 cm soil layers,the fractal dimensions of soil particles were extremely significantly negatively correlated with the content of soil micro-aggregates with particle diameters from 0.25-0.05 mm,and extremely significantly positively correlated with the content of soil micro-aggregates with particle diameters from 0.05-0.01 mm,from 0.005-0.001 mm and below 0.001 mm.In the 20-40 cm soil layers,the fractal dimensions of soil particles were extremely significantly positively correlated with the total nitrogen content,and insignificantly correlated with other physical and chemical indices.