[Impact of land use types on soil macropores in the loess region]

Soil hydraulic conductivity and macropores are important parameters for determining the proportion of precipitation infiltration, simulating soil water and solution transport and establishing the hydrologic model. To investigate the effect of land use types on macropores in soils, soil hydraulic properties, macroporosity and macropore connectivity under different land use types (locust forestland, grassland, farmland and apple forestland) in the loess region were measured by Hood infiltrometer and water retention curve. The results showed that the average hydraulic conductivities under locust forestland, grassland, farmland and apple forestland were 58.60 x 10(-6), 54.90 x 10(-6), 35.30 x10(-6), 23.40 x 10(-6) m x s(-1), respectively. The differences among land use types were statistically significant (P < 0.05). The effective macropores per unit area, macroporosity and macropore connectivity were highest in locust forestland and grassland, followed by farmland and apple forestland. As a consequence of vegetation restoration, macropores which developed by plant roots and animal activity had significantly improved the soil infiltration capability. Restoring woods and grasses should persist in the loess region.