Environmental Effect And Assessments Of Soil Phenols In The Pure Eucalyptus Plantations And The Mixed Forest

In this research, the types, content, distribution regularity of soil phenols and the mutual relation among soil phenols, soil enzyme and pH were analyzed were studied on the Eucalyptus plantations in different management model. Biological assessments of phenolic acids were made by applying on Eucalyptus seedling. The main results were as follows:(1) The successive planting Eucalyptus doesn’t caused decreasing of soil pH, but increase the soil bulk capacity, reduced the soil aeration and drain ability. Mixed forest of Eucalyptus and Acacia mangium could balance soil pH and optimize soil quality. Mixed forest of Eucalyptus and Dalbergia odorifera could increase the soil moisture conservation.(2) The total phenols and compound phenols were not imply the accumulation tendency in the soil of the successive planting Eucalyptus. The content of soil Phenols were increased in mixed forest of Eucalyptus and Dalbergia odorifera. The water-soluble phenol content was increased in the soil of the successive planting Eucalyptus, but doesn’t reach the level of soil toxicity effects. Water-soluble phenol content was less in the pure Dalbergia odorifera forest and mixed forest of Eucalyptus and Dalbergia odorifera than in the Pure Eucalyptus.(3) The phenolic acids were not imply the accumulation tendency in the soil of the successive planting Eucalyptus. The contents of phenolic acids were increased in mixed forests and Pure Dalbergia odorifera forest. In the soil of those woodlands, vanill acid content was the highest, benzoic acid, P-hydroxybenzoic acid content were take second place, and the ferulic acid and cinnamic acid content were the-lowest.(4) With decreasing of the soil pH, urease activity and polyphenol oxidase and water-soluble phenol activity decreased, acid phosphatase, total phenols, compound phenols and phenolic acids activity increased. Soil polyphenol oxidase has degradation on soil phenols in the successive planting Eucalyptus. Compound phenols were significantly positive with total phenols and phenolic acids, were significantly negative with water-soluble phenol.(5) In the tested parameters, the change rates of biomass and MDA could be sensitive and reliable screening criteria to phenolic acids and were suitable for differenting phenolic acids tolerance on Eucalyptus seedling. Hydroxybenzoic acid with the concentration of10mg·L-1and500mg·L-1, ferulic acid with the concentration of50mg·L-1produced a promotive effect on growth and physiological responses of the Eucalyptus seedling. Vanill acid, ferulic acid and cinnamic acid with high Concentration produces had an inhibition.