Soil aggregates and infiltration characteristics under different vegetations in Changwu tableland slope of northwestern China

Soil and water loss in loess tableland slope had been widely concerned as a hot issue. In this paper, sites with three vegetation types (Robinia pseudoacacia, Platycladus orientalis and grassland) located in Changwu tableland slope of northwestern China were chosen as research objects. Our aim is to explore the effects of different vegetation types on soil aggregates and infiltration capacity, the mean weight diameter (MWD) and fractal dimension (D) of soil water-stable aggregates in layer of 0-30 cm, the soil organic carbon content (SOC) and the steady infiltration rate (SIR) were measured on May 2016. The results showed that: the MWD and D of soil water-stable aggregates in layer of 0-30 cm, SOC and SIR in the site of R. pseudoacacia land were 2.63 mm, 2.60, 5.62 g/kg and 10.40 mm/min, respectively; in P. orientalis land, they were 3.67 mm, 2.60, 4.87 g/kg and 5.41 mm/min; in the grassland, they were 2.44 mm, 2.58, 6.07 g/kg and 12.45 mm/min. Results showed that soil structure, organic carbon content and infiltration capacity of grassland and R. pseudoacacia land performed better than that of P. orientalis land, and were beneficial to the conservation of soil and water in Changwu tableland slope. P. orientalis land showed the advantage of shaping large aggregates, while its soil organic carbon content and water infiltration capacity were relatively low and not advantaged for rainfall infiltration. So it is recommended to plant evergreen tree (Platycladus orientalis) moderately, and design rational distribution of different vegetation types in this area.