Study On The Ecologic Characters And Adaptability Of Desmodium Triflorum For Ground Cover

Desmodium triflorum and Kummerowia striata are two wild legumes found in Zoysia japonica turf in this research. Compared with Kummerowia striata, the morphological characters, growth and propagation characters, resistence, adaptability for ground-cover vegetation usage and the ecologic relationship with Zoysia japonica among the three grasses were studied and it could be concluded that Desmodium triflorum and Kummerowia striata are two promising wild species because of excellent biologic characters and ecologic characters for ground cover vegetation usage.Morphological characters The roots of three legumes can be classified into main root, secondary root and fibrous root. The root collar of Desmodium triflorum is obviously bulgy but it is not evedent for Kummerowia striata. The stalk can be classified into main stalk and secundary stalk, the quantity of main stalk is far more than the latter. Compound leaf consists of three folioles constructed by leaf blade, leaf stem and stipula. The stoma density is marketly affected by environmental conditions. Most of root nodules are inefficact and the nodule number of Desmodium triflorum is far more than Desmodium microphylum and Kummerowia striata. The flower is typical papilionaceous and fruit is pod. 2) Growth and propagation charactersThe growth rate of matured plant of the three speceis in summer is obviously faster than that in winter and the order is Desmodium triflorum＞Desmodium microphylum＞Kummerowia striata. The survival rate of cuuting seedling can be ordered as Kummerowia striata＞Desmodium triflorum＞Desmodium microphylum but the order of rootage speed is Desmodium triflorum＞Desmodium microphylum＞Kummerowia striata. The ratio of root and coronal of cuuting seedling can be described as "slow-fast-slow" along with time going. The seed ripening stage of Desmodium triflorum lasts for three months, the seeds of them are hardness and could hardly germinate under natural conditions. The germination percentage of the seeds also could be improved by soaking in concentrated sulfuric acid and then placing at 25℃ to 30℃ for 1 minute.3) ResistenceThe order of the ability for drought-resistence of the three speceis is Desmodium microphylum＞Kummerowia striata＞Desmodium triflorum, and it is Kummerowia striata＞Desmodium triflorum＞Desmodium microphylum for cold-resistence. The three speceis have outstanding adaptability to poor soil. The ability of talerance to Al3+ is ordered as Desmodium triflorum＞Desmodium microphylum, and the growth of Desmodium triflorum can be improved by low concentration aluminium. Two Desmodium have good shade tolerace but Desmodium microphylum is better. The affection of shading to the seedling of Desmodium microphylum in summer is serious but significantly reduced in fall and winter while matured.4) Adaptability for ground coverThe effect of weeds to Desmodium microphylum is very obvious at the initial stage and its morpha can be changed to some degree because of shading caused by weeds. Closer plant space could efficiently restrain the growth of weeds. The effect of nitrogen application to Desmodium microphylum can be described as: faster growth rate, larger leaf, darker leaf colour, higher height and coverage. The phodphorus application can imprive the growth performance of both aboveground and underground. Asexual propagation is the proper method for Desmodium microphylum. In despite of the excellent performance of Desmodium, fast speed for covering the ground, outstanding adaptability, beautiful landscape and low mowing freguenc, it should be noticed that it cannot stand high-level trample. The ranking based on the integrated evaluation for greening utilization is Desmodium microphylum＞Zoysia japonica＞mowed Desmodium microphylum＞Desmodium triflorum.5) The ecologic competition relationship with Zoysia japonicaThe random germination and fast growth of Desmodium microphylum in Zoysia japonica community under proper comditions increase its frequency. The height increase of Desmodium microphylum results in t...