Fractal geometry is an important method in soil science,and many studies have used fractal theory to examine soil properties and the relationships with other eco-environmental factors.However,there have been few studi...Fractal geometry is an important method in soil science,and many studies have used fractal theory to examine soil properties and the relationships with other eco-environmental factors.However,there have been few studies examining soil particle volume fractal dimension in alpine grasslands.To study the volume fractal dimension of soil particles （D） and its relationships with soil salt,soil nutrient and plant species diversity,we conducted an experiment on an alpine grassland under different disturbance degrees：non-disturbance （N0）,light disturbance （L）,moderate disturbance （M） and heavy disturbance （H）.The results showed that （1） Ds varied from 2.573 to 2.635 among the different disturbance degrees and increased with increasing degrees of disturbance.（2） Shannon-Wiener diversity index,Pielou＇s evenness index and Margalef richness index reached their highest values at the M degree,indicating that moderate disturbance is beneficial to the increase of plant species diversity.（3） In the L and M degrees,there was a significant positive correlation between D and clay content and a significant negative correlation between D and soil organic matter （SOM）.In the H degree,D was significantly and positively correlated with total salt （TS）.The results suggested that to a certain extent,D can be used to characterize the uniformity of soil texture in addition to soil fertility characteristics.（4） For the L degree,there was a significant negative correlation between D and the Shannon-Wiener diversity index; while for the M degree,there was a significant negative correlation between D and Pielou＇s evenness index.展开更多
Fractal method is a new method to estimate soil structure. It has been shown to be a useful tool in studies related to physical properties of soil as well as erosion and other hydrological processes. Fractal dimension...Fractal method is a new method to estimate soil structure. It has been shown to be a useful tool in studies related to physical properties of soil as well as erosion and other hydrological processes. Fractal dimension was used to study the soil structure in soil at different stages of vegetative succession on the Ziwuling Mountains. The land use and vegetation types included cultivated land, abandoned land, grassland, two types of shrub land, and three types of forests. The grassland, shrub land, and forested areas represented a continuum in vegetative succession that had occurred naturally, as the land was abandoned in 1862. Disturbed and undisturbed soil samples were collected from ten vegetation types from depths of 0-10, 10-20, and 20-30 cm on the Ziwuling Mountains, at a site with an elevation of about 1 500 m. Particle size distribution was determined by the pipette method and aggregate size distribution was determined by wet sieving. The results were used to calculate the particle and aggregate fractal dimension. The results showed that particle and aggregate fractal dimensions varied between vegetation types. There was a positive correlation between the particle fractal dimension and the weight of particles with diameter 〈 0.001 mm, but no relationship between particle fractal dimension and the other particle size classes. Particle fractal dimension was lower in vegetated soils compared to cropland and there was no consistent relationship between fractal dimension and vegetation type. Aggregate fractal dimension was positively correlated with the weight of 〉 0.25 mm aggregates. Aggregate fractal dimension was lower in vegetated soils compared with cropland. In contrast to particle fractal dimension, aggregate fractal dimension described changes in soil structure associated with vegetative succession. The results of this study indicate that aggregate fractal dimension is more effective in describing soil structure and function compared with particle fractal dimension.展开更多
土壤孔隙对水分、养分的运移起着重要作用,重构土壤孔隙状况反映着复垦土壤质量的高低。本研究基于Math Works Matlab(2009a)平台,在对土壤孔隙CT扫描图片三维重建的基础上,运用多重分形理论对安太堡露天煤矿不同复垦年限排土场重构土壤...土壤孔隙对水分、养分的运移起着重要作用,重构土壤孔隙状况反映着复垦土壤质量的高低。本研究基于Math Works Matlab(2009a)平台,在对土壤孔隙CT扫描图片三维重建的基础上,运用多重分形理论对安太堡露天煤矿不同复垦年限排土场重构土壤(23年、20年、0年)以及原地貌土壤进行三维多重分形定量表征,以探讨重构土壤孔隙空间分布规律。结果表明:重构土壤孔隙三维结构具有多重分形特征,信息熵维D1、广义维数谱曲线弯曲程度△D、多重分形谱谱宽△α随着复垦年限逐渐增大,土壤孔隙状况得到改善,土壤孔隙分布越趋于复杂,变异程度较高;重构土壤及原地貌土壤孔隙三维分布多重分形谱函数△f>0,呈左钩状,大概率孔隙占主要地位,孔隙分布不均匀。多重分形参数D1、D0-D1、△D、△α、△f间具有较好的相关性,从不同角度上反映了土壤孔隙三维分布的非均质性。展开更多
基金financially supported by the National Basic Research Program of China(2009CB825103)
文摘Fractal geometry is an important method in soil science,and many studies have used fractal theory to examine soil properties and the relationships with other eco-environmental factors.However,there have been few studies examining soil particle volume fractal dimension in alpine grasslands.To study the volume fractal dimension of soil particles （D） and its relationships with soil salt,soil nutrient and plant species diversity,we conducted an experiment on an alpine grassland under different disturbance degrees：non-disturbance （N0）,light disturbance （L）,moderate disturbance （M） and heavy disturbance （H）.The results showed that （1） Ds varied from 2.573 to 2.635 among the different disturbance degrees and increased with increasing degrees of disturbance.（2） Shannon-Wiener diversity index,Pielou＇s evenness index and Margalef richness index reached their highest values at the M degree,indicating that moderate disturbance is beneficial to the increase of plant species diversity.（3） In the L and M degrees,there was a significant positive correlation between D and clay content and a significant negative correlation between D and soil organic matter （SOM）.In the H degree,D was significantly and positively correlated with total salt （TS）.The results suggested that to a certain extent,D can be used to characterize the uniformity of soil texture in addition to soil fertility characteristics.（4） For the L degree,there was a significant negative correlation between D and the Shannon-Wiener diversity index; while for the M degree,there was a significant negative correlation between D and Pielou＇s evenness index.
基金funded by the National Natural Science Foundation of China(90302001)CAS Knowledge Innovation(KZCX3-SW-421)the Fund of the State Key Laboratory of Soil Erosion and DrylandFarming on the Loess Plateau(10501-152).
文摘Fractal method is a new method to estimate soil structure. It has been shown to be a useful tool in studies related to physical properties of soil as well as erosion and other hydrological processes. Fractal dimension was used to study the soil structure in soil at different stages of vegetative succession on the Ziwuling Mountains. The land use and vegetation types included cultivated land, abandoned land, grassland, two types of shrub land, and three types of forests. The grassland, shrub land, and forested areas represented a continuum in vegetative succession that had occurred naturally, as the land was abandoned in 1862. Disturbed and undisturbed soil samples were collected from ten vegetation types from depths of 0-10, 10-20, and 20-30 cm on the Ziwuling Mountains, at a site with an elevation of about 1 500 m. Particle size distribution was determined by the pipette method and aggregate size distribution was determined by wet sieving. The results were used to calculate the particle and aggregate fractal dimension. The results showed that particle and aggregate fractal dimensions varied between vegetation types. There was a positive correlation between the particle fractal dimension and the weight of particles with diameter 〈 0.001 mm, but no relationship between particle fractal dimension and the other particle size classes. Particle fractal dimension was lower in vegetated soils compared to cropland and there was no consistent relationship between fractal dimension and vegetation type. Aggregate fractal dimension was positively correlated with the weight of 〉 0.25 mm aggregates. Aggregate fractal dimension was lower in vegetated soils compared with cropland. In contrast to particle fractal dimension, aggregate fractal dimension described changes in soil structure associated with vegetative succession. The results of this study indicate that aggregate fractal dimension is more effective in describing soil structure and function compared with particle fractal dimension.
文摘土壤孔隙对水分、养分的运移起着重要作用,重构土壤孔隙状况反映着复垦土壤质量的高低。本研究基于Math Works Matlab(2009a)平台,在对土壤孔隙CT扫描图片三维重建的基础上,运用多重分形理论对安太堡露天煤矿不同复垦年限排土场重构土壤(23年、20年、0年)以及原地貌土壤进行三维多重分形定量表征,以探讨重构土壤孔隙空间分布规律。结果表明:重构土壤孔隙三维结构具有多重分形特征,信息熵维D1、广义维数谱曲线弯曲程度△D、多重分形谱谱宽△α随着复垦年限逐渐增大,土壤孔隙状况得到改善,土壤孔隙分布越趋于复杂,变异程度较高;重构土壤及原地貌土壤孔隙三维分布多重分形谱函数△f>0,呈左钩状,大概率孔隙占主要地位,孔隙分布不均匀。多重分形参数D1、D0-D1、△D、△α、△f间具有较好的相关性,从不同角度上反映了土壤孔隙三维分布的非均质性。
