| In this study, representative samples were collected from Hongjiannao Lakeside, eightsamples were collected in October2011, and ten samples were collected in June2012andOctober2012. The soil physic-chemical properties were analyzed. And the soil microbialdiversity was study by many microbiological measurements, including traditional culturetechniques, chloroform fumigation, Biolog system and PCR-DGGE. The results are shown asfollows:1. The soil pH value is7.93-9.92, this result revealed that soil were alkaline. Thecontent of organic matter, total N, total P, total K, nitrate nitrogen, Available P, Available K is1.37-2.96g·kg-1,0.007-0.722g·kg-1,0.215-0.904g·kg-1,17.59-25.46g·kg-1,1.18-5.90mg·kg-1,1.37-6.65mg·kg-1,35.72-228.29mg·kg-1, respectively. In addition to total P, total K andavailable P, the content of other nutrients are low, indicating that soil was barren. The contentof nutrients under different vegetations was significant differences, meanwhile seasonalvariation was also influence the soil nutrients.2. The quantity of microbes in soil of Hongjiannao is microbial bacteria>actinomycetes> fungi, the number of microorganisms in summer （2012.6） less than inautumn （2011.6and2012.10）. The culturable microbial species in autumn （2011.10） sampleswas10-20; in （2012.6） samples were5-22; in autumn （2012.10） samples were4-18. Threeperiods showed smaller changes in microbial species.3. Different samples in the same season, microbial biomass levels were significantlydifferent. Compare with the autumn （2011.6and2012.10）, microbial biomass content insummer （2012.6） is low, which is variation trend with the number of microorganisms changewith seasonal. In autumn （2011.6and2012.10） microbial respiration intensity was strangerthan in summer （2012.6）.4. AWCD value in Hongjiannao show an "S" curve change with time, in keeping withthe general microbial growth curves, adaptation period, logarithmic phase, stable growthperiods and periods of recession were exist in the whole growth stage.5. Soil microbial communities in the first autumn （2011.10） sampling, the number ofavailable carbon source is22-29.33. Microbial communities in summer （2012.10） samplingcan take advantage of0-23carbon species. Soil microbial community in autumn （2012.10） sampling can take advantage of9-28carbon species. By contrast, the number of carbonsources used by microbial communities in the summer was reducing.6. Shannon diversity index, McIntosh diversity index showed that: seasonal variations,soil nutrient content, types and coverage of vegetation make the microbial diversitydifferences. Shannon evenness among the first autumn （2011.10） samples was no significantdifference. But in summer （2012.6） and autumn （2012.10） there was significant differencebetween each samples. Diversity index in different soil samples also has significantdifferences. The result on six categories of utilization of carbon sources used by microbialcommunity showed has a maximum utilization of carbohydrates, and Polymeric compounds,carboxylic acids, amino acids have similar utilization. Polyamines and polyphenoliccompounds have a lowest utilization.7. Eight soil samples were collected in autumn （2011.10）,63bands were isolated fromsoil samples and enrichment samples. Ten samples were collected in summer （2012.6）,39bands were isolated soil samples and enrichment samples.10samples were collected insummer （2012.10）,42bands were isolated soil samples and enrichment samples. Culturableand free cultured DGGE profiles showed that samples cultured DGGE profile bands less thanfree cultured samples in the same sample. The bands are differences between culturable andfree cultured DGGE profiles. Some bands in cultured DGGE profiles do not appeared in freecultured DGGE profiles, so in order to more comprehensive study on soil microbialcommunity structure and diversity, it is necessary using a combination of methods. The typeand number of bands are not the same in different samples, because of the different type andcoverage of vegetation. Cluster analyses showed that in the DGGE profile free culturedsamples together and distance other samples. |
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