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| Fractal dimension of the soil aggregate and its responds to plant rehabilitation in the Hilly-gully region of Loess Plateau |
| An Shaoshan1,2,Zhang Yang1,3,Zheng Fenli1,3 |
| 1.Institute of Soil and Water Conservation,CAS & MWR,Northwest A&F University,712100,Yangling,Shaanxi;2.State Key Laboratory of Urban and Regional
Ecology,Research Center for Ecoevironmental Science,CAS,100085,Beijing;3.College of Resource and Environment,Northwest A&F University,712100,Yangling,Shaanxi: China |
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Abstract The characteristics of soil aggregates fractal dimension and its responses to vegetation rehabilitation were studied in the Hilly-gully region of Loess Plateau.The results indicated that: 1) In the beginning of rehabilitation,the >10 mm soil aggregates were higher both in 0-20 cm and 20-40 cm,which were between 331.4-525.6 g/kg.Along with the increasing of rehabilitation ages,10-7 mm,7-5 mm,5-3 mm,3-2 mm,2-1 mm soil aggregates declined,the contents of 1-0.5 mm,0.5-0.25 mm and 5 mm decreased quite fast.After seven years rehabilitation,big grade size aggregates were lower in surface layer than sub-surface layer.Compared to the result of dried sieving way,soil water stable aggregates had more even and stable distribution.Soil aggregates which >0.25 mm was mainly 40%-50% after 7 years rehabilitation,in total aggregates,but >5 mm soil aggregate was only 10%-23% approximately.During the process of vegetation rehabilitation,it had the trend that big size soil aggregates converted to small size aggregates,the granule size was more uniformity which showed that good soil structure was formed.3) The fractal dimension of soil aggregates in different rehabilitation ages were between 2.75-2.86 in the surface layer and 2.77-2.89 in the subsurface layer,soil fractal dimension was declined along with the rehabilitation years increasing.
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Received: 23 August 2007
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