Study On Distributing Pattern Of Legume Grass In Northeastern Natural Grassland In China

Legume pasture, with an extensively distribution in natural grassland, are increasingly valued by people due to high production, good taste and economic ability of N fixation. In meadow, steppe, desert or alpine meadow, as dominant species, constructive species or randomly distributing species, legume grass makes great contribution to the improvement of grassland quality. The growth and distribution of legume grass directly affect the development of grassland animal, recovery of damaged grassland and evaluation and management of healthy grassland ecosystem. This paper focused on the natural population distributing pattern and interspecific relations of some extensively distributing wild legume grass. In addition, the detail investigation and analysis of species composition, frequencies, abundance, diversity and equality of legume grass in community were conducted in this research. BQV method of Greig-Smith was used in inter- and intra-community levels to study the population distribution pattern of dominant legume grass in Songnen Plain and Inner Mongolian natural grassland. The results showed that: (1)All of the five legume grass in Songnen Plain displayed assembling distribution pattern at inter-community level, of which Lathyrus quinquenervius,Vicia multicaulis,Lathyrus hedysaroides,Lathyrus davurica displayed assembling distribution pattern at intra-community level, while Medicago ruthenica tended to be random distribution.(2) The distribution pattern of Medicago falcata in Inner Mongolia was assembling pattern but with great difference according to distributing environment; therefore, the situation showed the tendency of random distribution. On the other side, the relations among community classification, structure, diversity and distribution pattern were also investigated through the study of species composition, diversity and interspecific relation of Medicago falcata in Inner Mongolia. In the aspect of interspecific relation, 2×2 contingency table and Yates X2 test were used to test the relations among legume species and Ochiai, Dice, Jaccard, Yule indexes were used to analyze the type of interspecific relation, intensity of relation and minimal relation area. Finally, the research of Medicago falcata distribution strategy, inter-community diversity and its mechanism of variation was conducted through abundance index, diversity index, equality and inequality study in different communities. This paper aims to provide scientific evidence for proper utilization and management of grassland through distribution strategy and interspecific relation of legume grass in natural grassland, amplifying the active role of grassland legume.