POTENTIAL ROLE OF FUNGI AND BACTERIA IN CHINESE FIR REPLANT SOIL

The role of soil fungi and Bacillus in the Chinese fir (Cunninghamia l anceolata) replant problem was investigated. Several pathogenic fungi isolated were more abundant in replant than in non-replant woodland so il, but the species composition of soil bacteria showed no significant differences. Fumigation of replant soils with methyl bromide signific antly increased the growth of Chinese fir compared with nonfumigated s oils. Inoculation of steam-sterilized soil with the pathogenic fungi c aused significant reduction of growth of Chinese fir seedlings, while amendment with bacteria from the soil had no effect on seedling growth . However, the combination of pathogenic fungi and bacteria greatly re duced plant growth and increased root rot compared with pathogenic fun gi or bacteria alone. It is suggested that fungi alone or in combinati on with bacteria may be important biotic factors in the Chinese fir re plant problem.