| Soil microorganisms are important components of the forest ecosystem, it is also one of the important participants of ecological restoration, and plays an important role in formation and improvement of soil structure, effective plant nutrients, degradation of toxic substances and so on. The author used the method of chloroform fumigation extraction, dilution plate and "the BIOLOG Eco micro-tablet analysis" to research Cinnamomum camphora, Pinus massonian and camphor-masson pine mixed forest on soil microbial number, biomass carbon, nitrogen and community diversity effect in Subtropical region of China. The main results are listed as followed:(1)The number of soil microorganism of Cinnamomum camphora (L.) Presl, Pinus massoniana Lamb and the mixed forest have significant difference (p<0.05). Basic performance for total number of microbes, bacteria, fungi, actinomycetes: camphor forest> mixed> pine forest, there is a significant difference in the number (p<0.05)(2) Soil microbes not only their microbial populations in three forest types are different, and three community composed of3types of microorganisms are not the same. Camphor forests:bacterial71.56%, fungi14.37%, Actinomyces14.07%; mixed forests:bacterial59.28%, fungi19.79%, Actinomyces20.93%, pine forests:bacterial58.21%, fungi and21.57%, Actinomyces20.22%. Proportion of bacteria in soil under three forests characterized by forests of cinnamomum camphora> mixed> pine; fungi under different forest types in these three characteristics of Pinus massoniana> mixed> cinnamomum camphora; Actinomyces under different forest types in these three characteristics of camphor tree forest> mixed> Pinus massoniana. But overall,3in three forest communities in both classes of microorganisms bacteria, fungi, actinomycetes with highest proportion of bacteria (average62.51%), followed by Actinomycetes (average19.38%), fungus is relatively small (average18.11%)(3) The same variation of the three forest types in the total number of soil microbial season variation and soil bacteria. camphor forest and the mixed was: summer> spring> autumn> winter, pine forests was:winter> spring> summer> autumn. In the summer to reach the maximum value of483.87x104g-1dry soil (camphor forest), In the winter to reach the minimum of76.693x104g-1dry soil (pine forest); bacterial seasonal variation is inconsistent. The number of seasonal variation of camphor forest and mixed forest bacteria was summer> spring> autumn> winter, while pine forest seasonal variations for the winter> spring> summer> autumn.(4) Average annual content of the three forest types of soil microbial biomass carbon (MBC) is characterized by Pinus massoniana forest> mixed forest>camphor forest; microbial biomass nitrogen (MBN):camphor forest> Pinus massoniana forest> mixed forest, not significantly different (P>0.05). The seasonal variation of soil microbial biomass analysis:Soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) there are significant seasonal variation (P <0.05). Three forest types in soil microbial biomass carbon as follows:camphor and mixed forests are basically the same seasonal trend for the summer> spring> autumn> winter; masson pine as follows:summer> spring> winter> autumn; maximum in the summer value of mixed295.34mg/kg (mixed), the minimum mixed47.15mg/kg (masson pine) in the autumn; three forest types of soil microbial biomass nitrogen as follows:of the forest the content of the changing seasons as:summer> spring> autumn> winter; mixed as follows:winter> spring> autumn> summer; masson pine for: winter> summer> spring> autumn; in the summer to reach the maximum value of43.30mg/kg (camphor forest). In the autumn to reach a minimum value of2.91mg/kg (camphor forest)(5) Soil microbial biomass carbon and nitrogen and soil organic carbon, total nitrogen, carbon and nitrogen ratio was a significant linear correlation, microbial biomass carbon and nitrogen with soil moisture correlation is not significant, also exist between the microbial biomass was significantly linear correlation.(6) As to the value of the overall AWCD, their difference is very notable; This was reflecting the three forest types of physiological and functional diversity of soil microbial community for Cinnamomum camphor a and soil microbial activity most, followed by mixed forests, Pinus massonian, the lowest; In regard to the overall dominance, richness and uniformity of soil microbial community diversity, all features were Cinnamomum camphora>mixed forest>Pinus massonian; Through variance analysis of single carbon source, it found that:the soil using carbon source was focus on the Carbohydrates, amino acids and polymers. utilization level was also Cinnamomum camphora>mixed forest>Pinus massonian. To sum up, from the perspective of functional diversity of microbial, In addition to focusing on utilization of microorganisms on carbon sources, a should also be concerned about the role of microbes in other nutrient elements releasing.(7) Analysis of relationships between the factors, find that soil microbial diversity, organic carbon, microbial carbon and microbial nitrogen tends to be highly relevant, but moisture and the diversity of relations was not notable, and the nitrogen in the soil biodiversity impacts will be subject to further research. so this was indirectly proves the3forest types in the following some soil fertility indicators that result in microbiological activity and diversity of the difference. |
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