Study On Dynamic Variation Of Soil Microorganism Under Different Management Modes In Larix Gmelini Forest

In this article, the soil in forest is studied under different management modes in Mountain Daxing'anling in Inner Mongolia. Through testing the population of main types of soil microorganism, microbial biomass carbon and nitrogen,and soil engyme activities,analyzing their variation in different seasons and years,in order to gain scientific evidences in studying microorganism field to evaluate soil fertility and improve managing forest modes,the result is as following:1.The order of population of soil microorganism in forest is as following in different seasons: summer > spring > autumn;O > A > Ar > G under different management modes;Layer 1>Layer2>Layer3>Layer4 from up to down in different soil layers just like different years.The order of population of soil microorganism in forest is as following in different years:2007>2006>2008;O>G>Ar>A under different management modes; the order of 4 types of microorganism population is becateria> nitrogen fixing becateria>actinomycetes>fungi.2.The soil microbial biomass carbon in different seasons shows as following: spring>summer > autumn;Layer1 > Layer2> Layer3> Layer4 from up to down in vertical distribution; G>O>A>Ar under different management modes, in different years it shows as following: 2006>2008>2007; Layer2>Layer1>Layer3>Layer4 from up to down in vertical distribution; G>O>A>Ar under different management modes.The soil microbial biomass nitrogen in different season shows just like microbial carbon in different seasons except G>A>O>Ar under different management modes, in different years it shows as following: 2008>2006>2007; Layer2>Layer3>Layer1>Layer4; O>A>G>Ar under different management modes.3. Urease, protease and polygphenol activity shows Layer1>Layer2>Layer3>Layer4 from up to down in vertical distribution, incerface and invertase activity are both same in different soil layers.(1) Urease activity shows in different seasons as following: spring>autumn>summer; O>A>Ar>G in different management modes,in different years it shows as following: 2006>2007>2008; O>A>G>Ar under different management modes.(2) Protease activity shows in different seasons as following: spring>summer>autumn; O>G>A>Ar under different management modes, in different years it shows 2006>2008>2007;O>G>A>Ar under different management modes.(3) Incerface activity shows in different seasons as following: autumn>spring>summer, but their differences is not significient under different management modes; in different years incerface activity shows as following: 2007>2006>2008. O>A>G>Ar under different management modes but their differences are very little.(4) Polygphenol activity shows in different seasons as following: autumn>summer>spring, O>G>Ar>A under different management modes, in different years polygphenol activity shows as following: 2006>2007>2008; O>G>A>Ar under different management modes.(5) Inveertase activity shows in different seasons as following: spring>autumn>summer; G>Ar>O>A, under different management modes, in different years it shows as following: 2006>2007>2008, but it is similar between 2007 and 2008; Ar>G>A>O under different management modes.4.Soil waterlevel declines gradually from up to down in soil layers under different management modes among different seasons and different years.Air temperature is 2007>2006>2008.5. Correlative analysis shows as following: the population relation of every type of microorganism is significient. In different degree, the correlativity among the microorganism population, microbial biomass carbon and nitrogen, urease, protease, incerface, invertase, polygphenol activity, air temperature and soil waterlevel is significient. It is thought that it is practical and reasonable to evaluate the soil fertility to base on these facts.6. Study shows there are great differences among tested factors to soil fertility under different management modes. The soil microorganisms have great significance in discomposing soil organic material and returning forest nourishment. By and large, original forest is the best and most ideal management mode of all. All-cut forest grows slowly to resume forest, gradually cutting, it disturbs plants and animals and other creatures growing up in some low degree, so it is regarded as the best management mode. Artificial planting forest is essential to keep and improve forest ecology system permernantly. So it is thought that gradually cutting is the best way to manage forest,...