Study On The Seasonal Changes Of Soil Microbes Enzymatic Activities And Nutrients Element Under Subalpine Abies Faxoniana Forest In Western Sichuan

Soil microorganisms were sensitive indicatives of every variation in environmental conditions. It could response the change of ecosystem function earlier. Soil enzyme activity could also outstanding reflect the soil organic matter and fertility levels. Soil nutrient cycling was the cooperation between soil microorganism quantity and enzyme activity, and they were essential for soil quality and functionality. Subalpine Abies faxoniana forest in the western of China was an important part in subalpine. What’s more, subalpine Abies faxoniana forest had principle ecological functions such as water conservation, species conservation and other important ecological functions. Its diverse vegetation and soil association provided a natural laboratory for forest soil science studies. The understory environment of subalpine fir forests, which was low temperature, high humidity, seasonal freezing and thawing, was very different from coniferous forest. The experiment was carried out for the first time in September 2011, on the Abies faxoniana forest and its soil in MuGecuo scenic area of GanZi state in SiChuan province was chosed as the research object. The soil fertility seasonal dynamics of soil microorganism quantity, enzyme activity and nutrients element content of A1 layer were researched based on the period of the whole year positioning observation and research. They could reveal the microbial community structure and region-specific soil enzymes, and provided a reasonable plan for managing methods, also being important theoretical and experimental significance to improve forest productivity. The results showed as follows:(1) Soil microorganism quantity showed significant changes with the seasonal change. The quantity of bacteria was absolute advantage in the distribution of plots. The quantity of bacteria and fungi:they were July>May>September, the quantity of actinomycetes:they were September>July>November. Correlation analysis showed that there was highly significant (P<0.01) or significant (P<0.05) correlation among bacteria, fungi and actinomycetes.(2) Seasonal overall variation of enzyme activity was July>September>November. Correlation between enzyme activity showed that there was a significant positive correlation among the urease, sucrose and catalase (P<0.05).(3) Correlation analysis of soil microbial quantity and enzyme activity showed that the quantity of bacteria had significant positive correlation with the activity of 3 enzymes (P<0.05). The quantity of fungi had very significant positive correlation with catalase activity (P<0.01), and had significant positive correlation with sucrose activity (P<0.05).(4) Correlation analysis of soil microbial quantity and soil nutrients element showed that the quantity of bacteria had highly significant positive correlation with total K (P<0.01). The significant positive correlation among bacteria and organic、total P、 available N、available P were existed(P<0.05). The positive correlation among fungus and organic、total N、available K were significant(P<0.05), while the correlation among actinomycetes and total P、available N、available P were significant(P<0.05).(5) Correlation analysis of soil enzyme activity and soil nutrients element showed that urease had highly significant positive correlation with organic、total P、available N(P<0.01), and then had significant positive correlation with total N、total K、available P、 available K(P<0.05). The sucrose had highly significant positive correlation with total K (P<0.01), and then had significant positive correlation with organic、total N、total P、 available N. available K(P<0.05). The catalase had highly significant positive correlation with available P(P<0.01), and then had significant positive correlation with organic、total N、total K、available N、available K(P<0.05).(6) The principal component analysis showed that it had enough comprehensive reaction of original index information because of the soil fertility of the cumulated variance contribution ratio of the first four principal components reached 87.608%. The first component was 49.766%, and it contribution rate is higher, occupies an important position in all indicators.