INVESTIGATION OF THE FLUCTUATION OF MICROORGANIC POPULATIONS IN SOIL CULTIVATED WITH NGOC LINH GINSENG.

Abstract

                The study was carried out on samples of soil cultivated with Ngoc Linh ginseng (6 years old) in Quang Nam. The samples were collected during the rainy/dry seasons in 2013-2014 at different depths (0-15 cm, 15-30 cm). The analysis result of the soil showed that the soil had low pH (4-4.5), high humidity (44-55%), high porosity (47-67%). The determination result of the composition and

quantity of microorganisms showed that there existed representatives of the major microorganism groups in Ngoc Linh ginseng cultivating soil: bacteria (making up more than 90% of the total microorganisms), actinomycetes and fungi. With

the metabolic function variance, the group of cellulolytic microorganisms was dominant as compared to the groups of phosphate solubilizing and nitrogen-fixing microorganisms. In general, the number of microorganisms in each group did not vary noticeably from season to season but tend to decrease by the depth of the soil (10-100 times less at the depth of 15-30 cm).