Pedosphere 11(1): 73--76, 2001
ISSN 1002-0160/CN 32-1315/P
©2001 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of lanthanum on major microbial populations in red soil |
| CHU Hai-Yan, WANG Jun-Hua, XIE Zu-Bin, ZHU Jian-Guo, LI Zhen-Gao and CAO Zhi-Hong |
| Institute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008 (China) |
| ABSTRACT |
| Pure culture and pot culture experiments were carried out to study the effect of lanthanum (La) on bacteria, actinomyces and fungus, and some microbial physiological groups, nitrifier, azotobacter and phosphobacteria, in a red soil taken form the Ecological Experimental Station of Red Soil, the Chinese Academy of Sciences, Jiangxi Province. LaCl3 was added into media at levels of 0, 25, 50, 100, 150, 200, 250 and 500 mg L-1 in the pure culture experiment, and into soil samples in porcelain pots before rice growing at levels of 0, 6, 30, 150, 300, 600 and 900 mg kg-1 dry soil in the pot culture experiment. The populations of the three soil microbes in the pure culture experiment decreased with the addition level of La, indicating that La was toxic to the soil microbes in pure culture, and the sensitivity of the 3 major microbial types to La was in a decreasing order of actinomyces > bacteria > fungus. In the pot experiment, La had slightly stimulative effect on soil bacteria and actinomyces when applied at low concentrations while had inhibitory effect on soil bacteria, actinomyces and fungus at high concentrations. When the concentration of La was low, soil azotobacter was stimulated slightly while soil nitrifier was stimulated strongly and the maximum increase was up to 50%. When the concentration of La was high, both soil azotobacter and nitrifier were inhibited, and the inhibition of La to the nitrifier increased with La concentration. La added at all the levels had stimulative effect on soil inorganic and organic phosphobacteria. Among the 4 physiological groups, soil nitrifier was most sensitive to La, so, it might be reasonable to assume that soil nitrifier was a sensitive indicator for evaluating the biological and environmental effects of rare earths. |
| Key Words: lanthanum, microbial populations, physiological groups, rare earths, red soil |
| Citation: Chu, H. Y., Wang, J. H., Xie, Z. B., Zhu, J. G., Li, Z. G. and Cao, Z. H. 2001. Effect of lanthanum on major microbial populations in red soil. Pedosphere. 11(1): 73-76. |
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