尾巨桉幼苗根际土壤微生物分布特点及酶活性

Microorganism distribution and enzyme activity in rhizosphere soil of Eucalyptus urophglla×grandis seedlings

通过不同肥料（氮肥,磷肥,钾肥,桉树专用肥）的正交试验设计对尾巨桉幼苗进行培育,研究尾巨桉幼苗根际土壤微生物数量及分布规律,土壤酶活性特点。结果表明：尾巨桉幼苗根际土壤微生物主要集中在0-20 cm的土层中,随土层的加深数量逐渐减少;蔗糖酶、脲酶、过氧化氢酶3种酶随土层深度的增加酶活性依次减弱,以0-20 cm土层的酶活性最大。施肥对土壤微生物影响的大小顺序为：细菌〉真菌〉放线菌,其中尿素是主要影响因子;施肥对土壤酶活性影响显著,4种肥料对蔗糖酶活性,脲酶活性,过氧化氢酶活性的影响顺序为：尿素〉钾肥〉桉树专用肥〉磷肥。

In order to identify microorganism distribution and enzyme activity in the rhizosphere soil of Eucalyptus urophglla×grandis seedlings,four fertilizers（urea,phosphate fertilizer,potash fertilizer and special Eucalyptus urophglla×grandis fertilizer） were applied by orthogonal experiment.Results show that the rhizosphere microbes were mainly concentrated in the soil layer as deep as 0-20cm,and the quantity of the microbes gradually decreased with the deepening of the soil.The three enzymes-invertase,urease,and catalase-were also the most active in the soil layer above 20cm deep,the activity dropped as the soil deepened.Fertilizer application had a positive effect on the presence of soil microorganisms.The most affected was bacteria,the second fungi and the third actinomycetes.The main influent fertilizer was urea.Fertilizers were significantly positively related to activity of invertase,urease,and catalase.Among the four fertilizers used,urea showed the top influence and phosphate fertilizer the bottom,with potash and special Eucalyptus urophglla×grandis fertilize being the second and third.