Effect of rock fragments on macropores and water effluent in a forest soil in the stony mountains of the Loess Plateau, China

Abstract

Rock fragments exert important effects on soil water movement and macropores.However,they are not well-studied in forest hydrological processes. The results show that the steday effluent is markedly affected by the radius and density of macropores, especially the density of macropores with radii>1.4mm make up only 6.86% of the total,they contribute 67.4% to the variance of steady effluent rates. The area proportion of macropores can better explain the change in steady effluent rates than radii and density of macropores;the steady effluent rate is closely positively related to th area proportion of soil macropores. The increase of the volumetric content of rock fragments in the soil causes increase in the mean radius of the macropores, especially in the density of macropores with radius>1.4mm,but has little effect on the density of macropores with radius<1.4mm.These results show that the effects of rock fragments on the water effluent rate are exerted by affecting the radius and density of macropores to some extent.

Key words: Macropore, steady effluent, rock fragment, stony mountains, Loess Plateau.