Contribution of fine roots mechanical property of Poaceae grasses to soil erosion resistance on the Loess Plateau.

• Root tensile strength decreased with root diameter with a power law relationship. • Bromus inermis showed the high average tensile strength and soil cohesion. • High root density might help resist extreme external stress. • Bromus inerm is a good candidate to improve soil shear resistance. Plant roots play a key role in soil erosion process, but less studies are focused on analyze the soil erosion resistance in terms of grassland roots mechanical properties. The objective of this study was to examine the root diameter, root density, root tensile strength and soil shear strength for five typical and widely distributed Poaceae grasses in semi-arid regions, thus determine the contribution of roots of artificial grassland to soil erosion resistance. Results showed that the roots of five grasslands were densely distributed in the surface soils (0–10 cm). Bromus inermis had the strongest roots that characterized by the highest average tensile strength (40.2 MPa) The shear strength significantly increased as the vertical stress increased from 50 kPa to 300 kPa, but the degree varied with grassland types. Shear strength was also linearly correlated with root density when vertical pressure reached 300 kPa (p < 0.01, R2 = 0.47), indicating that high root density might help resist extreme external stress. Moreover, Bromus inermis showed a high soil cohesion of 122.7 kPa (next to the highest value of 128.71 kPa in Panicum virgatum). Overall, Bromus inermis showed the highest soil erosion resistance among these five grasslands, could be a good candidate in Poaceae artificial grasslands to improve soil shear strength for topsoil conservation. These findings have potential implications for understanding the contribution of Poaceae grasses' roots on the topsoil reinforcement, and provide a theoretical basis for artificial grassland establishment on soil erosion resistance on the Loess Plateau. [ABSTRACT FROM AUTHOR]