Spatial Variation Pattern Of Soil Microorganiism And Soil Enzyme Activity In Different Altitude At Taibai Mountain

This study is discussed vertical variation of soil fertility, soil carbon, soil microbial biomass and enzyme activity at Taibai Mountain which is divide to 19 elevation gradient with1700 ~ 3500 m. And explore soil acid phosphatase enzymatic reaction through the tool of kinetics and thermodynamics in typical forest which is representativeness. The major conclusions are as follows:(1)Soil fertility of layer A and B decrease with increasing of altitude; Total soil nutrient in layer O is higher than layer B, its water content, organic matter, alkali-hydro nitrogen, CEC,is far more than layer B; Soil organic matter, alkali-hydro nitrogen, total nitrogen content of layer B soil in 3 broad-leaved forest is significantly higher than in fir forest, and there was no significant difference with larch forest, alpine meadow; The available p content of sawtooth oak forest is significantly higher than other forest; Total potassium content is the highest in the sawtooth oak forest, and it was significantly higher than other forest; And available potassium, CEC, total phosphorus content no obvious change with forest changing; The available p content of broad-leaved forest in layer A was significantly higher than that of boreal forest and alpine meadow, and organic matter, alkali-hydro nitrogen, total nitrogen,total phosphorus, total potassium content change with forest there was no significant difference.(2) Soil carbon in layer A is much higher than layer A.; SOC, MBC is first increase and then decrease with increasing altitude gradient, which is higher in 2200 m ~ 2400 m of microbial biomass carbon and dissolved organic carbon had no obvious change; Layer A and B have different response to environmental factors: soil microbial biomass carbon, nitrogen,phosphorus A was significantly related with total nitrogen in layer, and they significantly related with soil pH in layer B.(3)Soil microbial biomass phosphorus decrease with altitude increasing, soil microbial biomass is first increase and then decrease when maximum value appeared in broad-leaved forest, the minimum in the boreal forest; Layer A and layer B of soil have different response to environmental factors: soil microbial biomass carbon, nitrogen, phosphorus in layer A was significantly related with total nitrogen where layer Bwas significantly related with soil pH.(4)Soil enzyme activity of C, N, P, S and hydrogen peroxide(except sucrase) were first increase after drop tendency with higher enzyme activity in 2200 m ~ 2400 m, sucrase increases and FDA hydrolase has no obviously trend along altitude gradient; Enzyme activity of β-glucosidase and N, P, FDA hydrolase decrease after increase with higher value in2200 m ~ 2400 m, and cellulosase, sucrase, catalase activity was increased with altitude with opposite regulation of aryl sulfatase; Total enzyme activity of layer A, B first increase after decrease,then became higher at high altitude area, when the largest value was appeared in2200 m. Enzyme activity in broad-leaved forest of typical forest in layer A, B greater than the boreal forest, where alpine meadow was between broad-leaved and boreal forest. Total enzyme activity of layer B in broad-leaved forest is higher than alpine meadow and boreal forest is minimal; Total enzyme activity in Layer A is different to layer B: it increases with altitude in broad-leaved forest when decrease in boreal forest; Enzyme activity was affected by temperature, organic matter, alkali-hydro nitrogen, total nitrogen while no influence with K(rapidly-available potassium and total potassium). Principal component comprehensive scores of soil enzyme activity was significantly related to total enzyme activity, also the scores was significantly associated with scores of soil physical and chemical properties in layer B while layer A was no relevant.(5) Except 3420 m, k、Km、Vmax of soil acid phosphatase have same trend which is first increase after decrease, and the maximum value appear at 2416 m, the minimum value appear at 1712 m; Soil Ea and △H* in addition to 2001 m, other values show the decrease along altitude; △S* at different elevation are negative, which showed that order is increase, and the2416 m has the higher order.Results show that : With the increase of altitude gradient, soil fertility levels decrease.Soil carbon and soil microbial quantity has good instruction function to soil fertility conditions.Vertical distribution of soil enzyme was consistency with soil physical and chemical properties, and it can be used as an reliable indexes for evaluation of soil fertility conditions on altitude gradient.Change along the elevation gradient, soil enzymatic reaction process was differ, high altitude had small energy consumption, less heat enzyme- substrate compounds combined with the weak, and low elevation was exact contrary.Soil ecological system of Qinling Taibai mountain was obviously responsed to elevation gradient based on environmental factorse,and emperature was the main influencing factors.