Comparative Studies On The Ecological Effects Of MyricaL. On Soil Improvement In Guizhou

Aiming at retrograde vegetation, serious water and soil loss, declining soil fertility as well as growing rocky desertification of Guizhou fragile eco-environment, aiming for the sustainable development of region, the study choose species which have more economic, ecological and social benefit, to plant forming a complete set. According to ecological and soil science principles, the paper studied comparatively the ecological effects on soil improvement of three more economic species in Myrica L. By the single -factor comparative study and the all-factor multivariate statistical analysis, the results showed:1. Water-related parameters were determined by P-V curve technique to evaluate the drought-tolerance of Myrica L. Three species to tolerate drought were put in decreasing order as following: Myrica nana, M. rubra, M. esculenta.2. The contents of N, P, K, total ash in leaves of Myrica are higher in first year than second year.3. There is a little difference in the shape among Myrica root nodules. However, nitrogen-fixing activities are obvious difference. The nitrogen-fixing activities of M nana are the strongest of all. Its maximum is 23.079nmolC2H4/g FW·min, higher 90.78% than M. esculenta, and 99.25% than M. rubra.4. Compared with M. rubra forest and M. esculenta forest, soil organic matter contents, soil particle composition, bulk density, porosity, water capacity of M nana forest, which are more high level, and further improve the conditions of soil permeability and storing water. Therefore, it improves soil.5. Compared with M. rubra forest and M esculenta forest, soil total N, total P, hydrolyzed N, readily available P, and readily available K contents of M nana forest are richer than these of M esculenta forest and M rubra forest.6. Nitrogen-fixing activities were positively correlated with soil total porosity, field capacity, organic matter, total N, hydrolyzed N, total N, readily available P,total K, readily available K contents, r = 0.168~0.987. Soil organic matter contents were significantly positively correlated with Nitrogen-fixing activities, r = 0.987. Total P was significantly positively correlated with hydrolyzed N, r = 0.999. The values of soil integrated fertility index showed: M nana forest > M esculenta forest > M. rubra forest.