Microbial diversity of soils mulched by different sized gravel.

Gravel mulch has been used as an agricultural water conservation measure for over three hundred years in China's semiarid regions. In this study, a 3-year gravel mulch experiment on slopes in the northwestern Loess Plateau was conducted to evaluate the impact that different sized gravel mulch and natural rainfall has on surface runoff, soil physicochemical properties and microbial communities. The following three treatments were investigated: small-sized gravel mulch (AG, 2-5 mm particle size), large-sized gravel mulch (BG, 40-60 mm particle size), and no gravel mulch as a control (CK).