云南元谋干热河谷区土壤微生物数量特征

Quantitative Characteristics of Soil Microorganism in Dry-Hot Valley,Yunnan Province

采用稀释平板法分析了该地区土壤微生物分布特征,结果表明,元谋干热河谷中分布的微生物以细菌占绝对优势,达微生物总数量的98.5%以上;微生物的数量分布大小顺序依次为：细菌,放线菌,真菌;其垂直动态明显：0~15 cm土层的微生物数量多于15~30 cm土层,细菌土层间数量差异极显著,而放线菌和真菌均不显著;有机质和土壤含水量与土壤微生物总数显著相关;细菌和放线菌与土壤含水量呈正相关,真菌则为负相关.变形土在剖面的第一、二层微生物数量都很少,且差异不大,但60~90 cm土层微生物数量突然大幅增加,细菌由124.963×104cfu.g-1（DW）增加至1996.198×104cfu.g-1（DW）,增加了近16倍;真菌的数量在90~110 cm土层有显著变化,由1.188×104cfu.g-1（DW）增加至6.923×104cfu.g-1（DW）,增长了5.8倍;放线菌则变化不大.

In order to provide mocrobiological evidence for vegetation restoration and reconstruction in the fragile ecology system in dry-hot valley, Yunnan Province, quantitative characteristics of soil microorganism in this area were researched in this paper by dilution-plate method. The results showed that bacteria accounted for more than 98.5% of total number of soil microorganisms in dry-hot valley, Yunnan Province, was dominant microorganism; the trend of quantity was bacteria〉actinomycete〉fungi; vertical distribution was obvious, and the amount of microorganisms in 0-15 cm soil layer was significantly much more than that of 15-30 cm, and amount of bacteria was significantly different between soil layers, while amount of actinomycete and fungi was not; there were significantly correlation between microorganism quantity and organic matters and soil moisture; amount of both bacteria and significantly were positive correlation with soil moisture, while amount of fungi was negative correlation with it. Microorganisms were little in two uppermost layers of profile of vertisols, and there was no distinct difference between them, but it ac- celerated significantly in 60-90 cm layer,amount of bacteria increasing from 124. 963× 10^4 cfu.g-1 （DW） to 1 996. 198 × 10^4 CfU .g-1 （DW） ,the latter was nearly 16 times of the former; and amount of fungi changed significantly in 90-110 cm layer,from 1. 188× 10^4 cfu.g-1 （DW） to 6. 923× 10^4 cfu.g 1 （DW）, 5.8 times increased; amount of actinomycete did not show significant change.