Soil physical properties response to tillage practices during summer fallow of dryland winter wheat field on the Loess Plateau.

Soil physical properties are a greatly important part of the soil and indicator of soil quality, which can directly affect soil nutrient turnover and crop yields in dryland. This study was carried out with three tillage practices during the summer fallow season since 2011, including no tillage (NT), plow tillage (PT), and subsoiling (ST) in dryland winter wheat fields of the Loess Plateau. Results showed that soil tillage during the summer fallow had a small effect on soil bulk density (ρ b ) in the 0-50-cm soil profile before sowing and after harvesting of winter wheat. Soil ρ b under NT at a depth of 20-30 cm was significantly greater than those under PT in both seasons. Both soil gravimetric water content (θ g ) and volumetric moisture content (θ v ) after harvesting increased by 28.8-78.6% and 37.5-87.3%, respectively, compared with those before sowing. Adoption of PT significantly increased soil θ g and θ v in the entire 0-50-cm profile before sowing compared with NT and ST (P < 0.05). In addition, there was a small effect on soil porosity (e.g., total porosity, air-filled porosity, and capillary porosity) in the profile of 0-50 cm both before sowing and after harvesting. Overall, short-term tillage during summer fallow mainly affected soil water content in the 0-50-cm soil profile, and it had a slight effect on other physical soil properties.