Abstract: In this paper,the characters of soil aggregates under different skidding modes were investigated by fractal theory.The results showed that the particle fraction of soil aggregates was smaller under tractor-than under animal traction skidding.As for different parts of skidding road,the particle fraction of air-dried soil aggregates was in the order of bottom (2.309) > middle (2.291) > upper (2.014),while that of water-stable aggregates followed the sequence of bottom (2.04) < middle (2.143) < upper (2.262).The particle fraction of aggregates was 2.215 in forest soil and 2.175 in skidding roads.Skidding movement could improve soil aggregates when the cutting intensity was 15%.Tractor skidding was more favorable for soil aggregates formation.

Key words: Tamarix, Water physiology