Abstract: The effect of fast-growing Eucalyptus on soil organic matter content and pH were studied. The results showed that, planting Eucalyptus had the greater impact on the organic matter content in the soil of 10 cm and 20 cm depth, compared with the control, the decline of organic matter content reached 16.32% and 23.94%, respectively; 1~3-year-old Eucalyptus mainly affects 10~20 cm soil organic matter content, and 5-year-old Eucalyptus will affect 10~40 cm soil organic matter content; Planting fast-growing Eucalyptus would lead to the increase of soil pH value in cultivated land, which had little impact on soil pH in 10 cm and 30 cm layers, and had a greater impact on soil pH in 40 cm layers; From the perspective of planting year, planting Eucalyptus had little impact on soil pH in the first year, and had the greatest impact in the fifth year. Planting Eucalyptus has a significant impact on soil organic matter and pH, especially 5-year-old eucalyptus has the greatest impact on soil, it is suggested to taking relevant measures to protect cultivated land soil environment.

Key words: fast-growing Eucalyptus robusta, planting year, soil, organic matter content, pH