Water repellency as conditioned by physical and chemical parameters in grassland soil

- SWR reached a peak value of 80 s when the soil water content was 10.7%.
- WDPT values and soil water contents existed a one-peak distribution.
- Water repellency of the soil samples decreased with increasing soil grain size.
- SWR was positively correlated with total N, available N and organic matter contents.

The occurrence and consequences of soil water repellency (SWR) have been reported in many parts of the world, but little is known on the reasons and mechanisms of SWR in grasslands. Although considerable advances have been made in the past 10 years in understanding the impact of hydrophobic organic compounds on water repellency, there is still a considerable amount to be learnt. Of particular importance is the interaction between soil chemical characteristics and SWR in soil. The research gaps and seeks to understand how soil water repellency in grasslands of Inner Mongolia is influenced by soil chemical properties. The SWR of soil samples (n = 80) at the surface of the grassland (0-10 cm) collected in Xi Linhot was measured using the Water Drop Penetration Time Test (WDPT), and the relationship between soil chemical properties (e.g. soil organic matter, SOM) and SWR was studied in grassland soils. Results showed that SWR reached a peak value with an average of 80 s when the soil water content was 10.7%, the relationship between WDPT values and soil water contents showed a one-peak distribution. Soil water repellency increased exponentially with organic matter contents, total N, and available N and poorly correlated with carbonate, available P, available K and pH in grassland soils. Our results can provide the influencing factors of soil water repellency and promote soil amelioration.