1 Section of Biology and Environmental Science, The Faculty of Engineering and Science, Aalborg University, VBN2 Department of Chemistry and Bioscience, The Faculty of Engineering and Science, Aalborg University, VBN3 The Faculty of Engineering and Science (ENG), Aalborg University, VBN4 Institut for Agroøkologi - Jordfysik og Hydropedologi5 Ghent University6 Department of Civil Engineering, The Faculty of Engineering and Science, Aalborg University, VBN7 Ghent University
Though both above- and belowground components of vegetation act together in reducing soil erosion, mainly the aboveground component has received attention in past research. Therefore, the aim of this research was to evaluate the contribution of roots in soil erosion control. Perennial ryegrass (Lolium perenne L. Hugo) was grown in soil pans and laboratory rainfall simulation experiments were conducted after 4, 8, 12 weeks of their growth with seeding density of 50 kg ha-1, after 4 weeks for seeding density of 100 kg ha-1 and on a control. The experiments with ryegrass were done (1) in presence of complete plants and (2) after clipping off the shoots. Roots of ryegrass grew rapidly, attaining densities of 0.614 kg m−2 and 2.280 kg m−2 in 4 and 12 weeks respectively. There was no significant influence of root density alone in runoff whereas presence of shoots decreased runoff over control. With increasing root density, splash erosion decreased linearly and wash decreased exponentially. There was 67% reduction in total soil loss in 12 weeks as compared to control, mainly due to increase in soil’s shear strength and aggregate stability with roots. No inﬂuence of roots on bulk density and saturated hydraulic conductivity was observed.