龙脊梯田不同土地利用方式下土壤粒径分形特征

Fractal characteristics of soil particle under different land use patterns in Longji terrace

分析龙脊梯田不同土地利用方式土壤粒径分布规律,为龙脊梯田森林水源涵养、稻田耕作管理提供参考依据。以龙脊梯田竹林、杉木林、混交林和稻田四种土地利用方式为研究对象,测定土壤颗粒粒径和基本物理性质,计算土壤粒径分形参数,基于主成分分析、相关分析和逐步回归分析探讨土地利用方式对土壤粒径分形特征的影响。结果表明,杉木林粘粒含量最高,竹林砂粒含量最高,不同土地利用方式下的土壤粒径均主要分布在2~200μm,约占79.4%。多重分形维数中容量维D(0)、信息维D(1)、关联维D(2)值依次为杉木林>混交林>稻田>竹林,信息维/容量维D(1)/D(0)和单重分形维数D值依次为杉木林>竹林>稻田>混交林,奇异谱函数的谱宽△α和对称度△f均为混交林最大、稻田最小。D和△f分别与土壤粘粒和砂粒含量相关性最密切(P<0.01),D(0)和D(1)/D(0)与土壤粉粒含量相关性最密切(P<0.05)。土地利用方式可通过影响土壤机械组成来改变分形参数的大小,杉木林的土壤D、D(0)、D(1)、D(2)、D(1)/D(0)值均最大。

The aims of this study were to analyze the distribution of soil particle size in the context of different land use patterns on the Longji terrace and to provide a reference basis for forest water conservation and paddy field farming management.Taking bamboo forest,Chinese fir forest,mixed forest and paddy field as the research objects,the soil particle size and physical properties were measured.The fractal parameters of soil particle size were also calculated.The influence of land use patterns on the fractal characteristics of soil particle size was examined based on principal component analysis,correlation analysis and stepwise regression analysis.The results showed that the clay content in Chinese fir forest and the sand content in bamboo forest were the highest.The soil particle size from different land use patterns was mainly 2~200μm,representing approximately 79.4%of samples.The values for volume dimension D(0),information dimension D(1)and correlation dimension D(2)were Chinese fir forest>mixed forest>paddy field>bamboo forest.The values for information dimension/volume dimension D(1)/D(0)and single fractal dimension D were Chinese fir forest>bamboo forest>paddy field>mixed forest.The spectral width△αand symmetry degree△f of the singular spectral function were the largest for mixed forests and the smallest for paddy field.D was closely related to the soil clay content(P<0.01).D(0),D(1)/D(0)and△f were closely related to the soil silt content(P<0.05).Land use patterns could change the fractal parameters by affecting the soil mechanical composition.The values of D,D(0),D(1),D(2),D(1)/D(0)of Chinese fir forest were the largest.