Fractal features of soil profiles under different land use patterns on the Loess Plateau, China

Abstract

Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution (PSD) and micro-aggregates in the 0-500 cm soil profile and soil anti-erodibility in the 0-10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou Watershed on the Loess Plateau, China. The 10 typical land use patterns were: slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0-40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0-10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.

Change in Soil Particle Size Distribution and Erodibility with Latitude and Vegetation Restoration Chronosequence on the Loess Plateau, China

“…TN was determined by the Kjeldahl method [25], and TP was determined by molybdenum antimony blue colorimetry [26]. The PSD of soil and microaggregate distribution were measured according to Xiao [3]. When determining soil PSD, samples were pretreated with 6% H 2 O 2 and 10% HCL, and soaked in distilled water for 24 h. After removing the distilled water, the samples were chemically dispersed with 0.4% Calgon, and were mechanically dispersed in an ultrasonic bath for 5 min.…”

“…To restore the eco-environment, the Chinese government launched the state-funded "Grain to Green" project in 1999 [2], through which many cropland areas were converted back to forestland or grassland, or were abandoned to allow natural recovery. The large-scale implementation of returning farmland to forests over several years has brought the soil erosion problem under control in some areas of the Loess Plateau [3].…”

Permeability Evolution and Particle Size Distribution of Saturated Crushed Sandstone under Compression

“…In addition, Mandelbrot [12], Turcotte [13] and Xie and Pariseau [14] proposed the fractal theory and thought the calculated parameters of particle size distribution are more easily to be assessed via fractal theory. Furthermore, fractal theory is a powerful tool used to characterize phenomena that exhibit large, scaleinvariant, and self-similar characteristics [15][16][17][18][19]. It has been widely used in geotechnical engineering to describe the evolution of particle size distribution, especially in soils [15,16,[20][21][22].…”

Fractal analysis in the description of soil particle-size distribution under different land-use patterns in Southern Amazonas State, Brazil

“…Compositions difference of the soil particles sizes exhibit fractal features with irregular shapes and structures of self-similarity (Tyler and Wheatcraft, 1992). This aroused the academic community to use the fractal as an effective descriptive tool to characterize the size of the soil particles' (Prosperini and Perugini, 2008;Xia et al, 2015), structure, aggregation and soil erodibility (Ahmadi et al, 2011;Xu et al, 2013;Tang et al, 2013;Xiao et al, 2014).…”