Characteristics of Soil Microorganisms in a Eucalyptus ABL12 Plantation

【摘要】：The study determined the variation pattern of soil microorganisms, soil biological activity, soil enzyme activity and soil nutrient status in a Eucalyptus ABL12 plantation with different undergrowth during May, 2004 to Jan., 2005, located in Danzhou, western Hainan Province. The results indicated that, the soil microbial properties and soil nutrients of the Eucalyptus stand were lower than those of the controls, the vegetable field and rubber tree stand. The numbers of soil microorganisms, soil biological activity, soil enzyme activity and soil nutrients were recorded highest in vegetable field, followed at a decreasing order by rubber tree plantation, legume-intercropped plot, herbage-intercropped plot and monoculture plot. All the parameters measured showed a tendency of vertical variation, i.e., decrease with the increase of soil depth. Seasonal variation was also observed in the numbers of soil microorganism, soil biological activity and soil enzyme activity with a single peak curve pattern that occurred in September and October at large. Bacteria were found to be the most abundant, followed by actinomycetes and fungi. These results demonstrated that intercropping E.ABL12 with tropical legumes has improved largely the soil environment for the soil microorganisms to live in, indicative of the better soil microbiological properties and soil nutrient levels.