Soil samples under different land uses

including woodland

cultivated dryland and orchard

were collected from profile horizons which derived from main parent materials (including basalt

sand-shale

Quaternary red soil and granite) in Guangdong Province

soil physico-chemical properties such as soil particle-size composition

organic matter

CEC

etc. were determined. The fractal dimension of particle-size distribution (PSD) for soils derived from different parent materials and its relationship with soil properties were studied. The results indicated that

the range of fractal dimension of PSD for soils derived from basalt

Quaternary red soil

granite and sand-shale were 2.923 9 to 2.981 2

2.858 8 to 2.937 7

2.769 3 to 2.923 1

and 2.544 6 to 2.885 6

respectively. The fractal dimension of PSD for soils derived from basalt

Quaternary red soil and sand-shale were significantly different. The fractal dimension of soil PSD showed an increasing trend with increasing soil depth

and the fractal dimension of soil PSD was almost the same in deep horizons of soils derived from the same parent material. The fractal dimension of soil PSD had smaller variation between soil at different depth in soil profiles derived from basalt and Quaternary red soil

however

the variation was larger for soils derived from sand-shale and granite. The fractal dimension of soil PSD was significantly negatively correlated with sand content

but was significantly positively correlated with clay content

soil total P

available K

total Fe

CEC

soil organic matter

total N

available N. The fractal dimension of soil PSD could be applied as a quantitative index reflecting soil fertility.