Study On Slope Protection Properties Of Four Warm-season Turfgrasses

This research, which aims at the majority of the imported lawn grass kinds in current domestic herbal plants on the slopes, the uniform variety, the high price, the poor ecological adaptability and the heavy workload on further maintenance and management of imported lawn grass kinds, from developing the abundant wild plant resources in China, taking U.S. Bahiagrass(Paspalum notatum) which is widely distributed and highly adaptable in hunan province, Changsha local bermudagrass (Cynodon dactylon), Changsha local Centipedegrass (Eremochloa ophiuroides), China Zoysia (Zoysia sinica) of Qingdao in Shandong province as the research object, carries out systemic study on four kinds of warm-season turf grass stems and leaves of hydro-ecological effect and the mechanics effect of root system at the first time in order to provide a scientific theory of ecological engineering such as popularizing and taking use of the plant on slope protection and vegetation recovery and so on.(1) Cynodon dactylon's turfing speed is seemly higher than other three warm-season lawn grass kinds', and the turfing speed from high to low lists as follows:Cynodon dactylon> Paspalum notatum> Eremochloa ophiuroides> Zoysia sinica. The slope has a significant impact on lawn grass's turfing speed. The lawn grass's turfing speed is inversely proportional to change of the slope of the lawn. The time of four warm-season lawn grass's turfing is the shortest under the condition that the slope is 0°and with the increase of the slope, the lawn's turfing speed turns lower and the time of turfing turns longer.(2) From the beginning of the turfing to the florescence, the Paspalum notatum's layer cover-degree maintains the high speed of increasing; Eremochloa ophiuroides and Zoysia sinica's layer cover-degree change little and even decrease; Cynodon dactylon's layer cover-degree maintains the high speed at the beginning as well, while as the cover-degree reaches 100%, under which condition the grass layer cover-degree gets up to the maximum value, the speed turns lower. The Paspalum notatum's layer cover-degree is more than other three lawn grass kinds', and the difference of the grass layer cover-degree lists as follows:Paspalum notatum> Cynodon dactylon> Zoysia sinica's> Eremochloa ophiuroides. However, with the change of the slope, one kind of lawn grass changes a lot. (3) From the end of turfing to the florescence, Paspalum notatum and Cynodon dactylon tiller fast and have a strong growth, but Zoysia sinica and Eremochloa ophiuroides grow lower than those mentioned above. The fresh weight of Paspalum notatum's stems and leaves reaches the maximum 213.01 t/hm2, and the dry weight reaches 66.48 t/hm2, which is heavier than other three grass kinds'. The kind of the grass and the slope of the lawn have a great impact on biomass on lawn grass, and the biomass of the four warm-season lawn grass under every integrated slopes in order from large to small lists as follows:Paspalum notatum> Cynodon dactylon> Eremochloa ophiuroides> Zoysia sinica.(4) With its lush stems and leaves, Paspalum notatum's stems and leaves interception effect is more remarkable than other three lawn grass kinds'. The slope has a significant effect on lawn grass maximum interception amount, and through the synthetic analysis on the four warm-season lawn grass under the conditions of different slopes, the stems and leaves interception effect of the four lawn grass kind arrange in order as follows:Paspalum notatum> Cynodon dactylon> Eremochloa ophiuroides> Zoysia sinica.(5) The average maximum compressive stress of the four warm-season lawn grass's root system lists in order as follows:Paspalum notatum 11.06 N> Eremochloa ophiuroides 9.05 N> Zoysia sinica 5.92 N> Cynodon dactylon 5.06 N, and the average tensile strength lists in order as follows:Paspalum notatum 34.64 mPa> Eremochloa ophiuroides 27.58 mPa> Cynodon dactylon 26.31 mPa> Zoysia sinica 22.82 mPa. The compressive stress and the tensile strength of Paspalum notatum is much more than other three grass kinds'. The maximum compressive stress of the four warm-season lawn grass's root system is in direct linear proportional to the root diameter while the tensile strength is inversely proportional to the root diameter.(6) The four grass kinds significantly enlarge the maximum shearing force of the soil and under the same vertical pressure Paspalum notatum's shearing force of the soil is much more than other three kinds', Different slopes and different kinds of plant play a role in influencing the strength of the shearing force of the soil. Under the natural condition (vertical pressure 10kPa), shearing force of the soil of the four grass kinds arranges in order as follows:Paspalum notatum> Eremochloa ophiuroides>Cynodon dactylon> Zoysia sinica:The influence of these four grass kinds' root system on the strength of the shearing force of the soil is accomplished by increasing cohesion of the soil.