| Recently, Eucalyptus have been broad planted in many south region of china asone of the three main plantation trees in the world,its economical values and socialvalues have gained extended identity, but at the same time its ecological values remainbeing disputed.Although our study group had studied on the soil microorganism andsoil fauna and soil nutrient in Eucalyptus grandis plantation, the soilenzyme,especially the rhizosphere environment which is nearly correlated withgrowth of vegetation have not been studied.In order to discuss more ecological valuesin Eucalyptus grandis plantation,offer academic reference for enlarging its plantingarea, we studied on the dynamic change and uprightness distribution of rhizospheresoil microorganism and rhizosphere soil enzyme activity in Eucalyptus grandisplantation in hong-ya county;meanwhile,we compared rhizosphere soilmicroorganism and rhizosphere soil enzyme activity and rhizosphere soil nutrientwith other using ways.The results showed:1.In the two Eucalyptus grandis plantation,the composing of rhizosphere andnon-rhizosphere soil microorganism were the same,the aerobic bacteria was themost,the actinomycetes took the second place,the fungi was the least.Except seasonchanges of rhizosphere and non-rhizosphere soil fungi was not the same, the seasonchanges of rhizosphere and non-rhizosphere of soil aerobic bacteria and soilactinomycetes and soil total microorganism were the same.The aerobic bacteria andtotal microorganism were the highest in autumn and the lowest in winter;Theactinomycetes was the highest in spring and the lowest in winter;The rhizospherefungi was the highest in autumn and the lowest in winter, the non-rhizosphere fungi was the highest in spring and the lowest in winter.The average microorganism's R/Sof four seasons in Eucalyptus grandis plantation is 1.40,the aerobic bacteria's averageR/S of four seasons is 1.40,the actinomyeetes's average R/S of four seasons is 1.40,thefungi's average R/S of four seasons is 1.41.The uprightness distribution rule ofrhizosphere and non-rhizosphere soil microorganism in Eucalyptus grandis plantationwere the same,the trend is surface layer(0-20cm)＞middle layer(20-40cm)＞underlayer(40-60cm).Compared with the amount of microorganism in 2004, the amount ofmicroorganism in 2006 had a definite drop.2.The season changes of soil enzyme activity of rhizosphere and non-rhizospherein Eucalyptus grandis plantation were the same,sucrase activity and urease activitywere the highest in Summer and the lowest in spring;catalase activity was the highestin autumn and the lowest in spring.The uprightness distribution rule of rhizosphereand non-rhizosphere soil enzyme in Eucalyptus grandis plantation were the same asthe microorganism,the trend is surface layer(0-20cm)＞middle layer(20-40cm)＞under layer(40-60cm).The sucrase aetivity's average R/S is 1.54,the urease activity'saverage R/S is 1.29,the catalase activity's average R/S is 1.39.3.Through studied on the rhizosphere soil microorganism and rhizosphere soilenzyme avtivity and rhizosphere soil nutrient of surface layer in different usingways,we found that many rhizosphere agrobiology factors and rhizosphere soilnutrient factors in Eucalyptus grandis plantation were better than in Quercusacutissima secondary forest.Except rapidly available K was extreme significant lowerthan Quercus acutissima secondary forest,the other factors were higher than inQuercus acutissima secondary forest,and many factors were significant or extremesignificant higher than in Quercus acutissima secondary forest.4.The rhizosphere soil microorganism and rhizosphere soil enzyme activity werepositive correlated with each other.Except aerobic bacteria and actinomycetes andfungi did not achieve significant or extreme significant correlation with urease,theother factors all achieved significant or extreme significantcorrelation.Besides,through a correlation analysis between rhizosphere agrobiologyand rhizosphere soil nutrient,except rapidly available K was negative correlation with urease and catalase,the other agrobiology factors were positive correlation with soilnutrient, aerobic bacteria and sucrase and catalase were extreme significantcorrelation with alkaline hydrolytic N and organism matter and rapidly available P;actinomycetes was extreme significant correlation with all soil nutrient factors;fungiwas extreme significant correlation with alkaline hydrolytic N and organism matterand rapidly available P, significant correlation with rapidly available K;urease wasextreme significant correlation with alkaline hydrolytic N, significant correlation withrapidly available P.5.Through the pathway analysis,rapidly available P and alkaline hydrolytic N andsucrase and catalase were the main influencing factors of total microorganism;ureaseand rapidly available P and alkaline hydrolytic N and catalase were the maininfluencing factors of sucrase; rapidly available P and sucrase and catalase were themain influencing factors of urease;urease and sucrase and rapidly available P were themain influencing factors of catalase.6.Imitated the model of rhizosphere soil nutrient: alkaline hydrolytic N: Y1=1.112×10-10+0.371A1+2.601A2-2.511A3+1.002A4 A1 delegate Aerobic Bacteria, A2 delegate Actinomycete, A3 delegate Epiphyte,A4delegate Urease rapidly available K: Y2=-2.03×10-10-0.439B1-4.304B2+6.377B3-0.907B4-1.65B5+0.446B6 B1 delegate Aerobic Bacteria, B2 delegate Actinomycete, B3 delegate Epiphyte,B4 delegate Sucrase, B5 delegate Urease, B6 delegate Catalase rapidly available P: Y3=1.225×10-11+1.773C1-1.279C2+0.492C3+0.221C4 C1 delegate Actinomycete, C2 delegate Epiphyte, C3 delegate Sucrase, C4 delegateUrease organism matter: Y4=-1.99×10-15+10.846D1-13.37D2+4.064D3D1 delegate Actinomycete, D2 delegate Epiphyte, D3 delegate Sucrase...
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