Enhanced soil stabilisation and growth of Lolium perenne through combined seeding with Cynodon dactylon

Herbaceous plants play a crucial role in soil stabilisation, and combined seeding is often employed in ecosystem management to promote biodiversity. This study investigated the influence of combined seeding of Ryegrass (Lolium perenne) and Bermuda (Cynodon dactylon) on plant growth and soil stabilisation through in-situ sampling and indoor experimental measurements. Four experimental plots were established: a. bare soil, b. L. perenne single species, c. C. dactylon single species, d. combined L. perenne and C. dactylon. The results indicate that combined seeding inhibited the development of L. perenne and C. dactylon root depth by 14.50% and 29.20%, respectively. However, shoot height, total leaf area, total root length and total root surface area increased in L. perenne under combined seeding, while these parameters decreased for C. dactylon. Combined seeding significantly enhanced the resistance to breakage in tension and tensile strength of L. perenne, with no significant impact on C. dactylon. Plant roots notably increased soil cohesion, with a respective increase of 37.08%, 26.98%, and 50.81% in cohesion for L. perenne single species plot, C. dactylon single species plot, and combined L. perenne and C. dactylon plot compared to bare soil. The root content in combined seeding significantly increased, with an increase of 27.17% and 65.20% compared to single seeding of L. perenne and C. dactylon, respectively. Additionally, under the influence of roots, the soil moisture content in the combined seeding plot was lower than in the single species and bare soil plots. These findings highlight that combined seeding enhanced plant competition, improved soil shear strength, and provided significant ecological benefits, offering insights for vegetation-based slope design.