Effects of some forest Tree Species on Soil Properties in Chittagong University Campus, Bangladesh

In the present study, a comparison was done between soil properties of forest plantations and adjacent unplanted plots at 14 sites within Chittagong University Campus. The sites were at nearly level topography and the soils were basically uniform with sandy loam to sandy clay loam, moderately to strongly acid, poorly fertile surface. Acacia auriculiformis A. Cunn. Ex. Benth., Eucalyptus camaldulensis Dehnh., Lagerstroemia speciosa (L.) Pers. And Swietenia mahagoni (L.) Jacq. Have been grown for various periods in each of three of the studied sites. In the remaining two sites, there were plantations of Hope a odorata Roxb. Data show that soils under the plantations had significantly higher organic carbon, total N, available K and Mg. On the other hand, both pH and available Ca were lower in soils under plantations than in the adjacent unplanted plots. The difference was more pronounced in the surface soil than the subsoil. The C/N, K/Ca, Mg/Ca and K/Ca + Mg ratios were higher in the plantations indicating substantial removal of N and Ca by the tree crops. However, there was no definite trend of variation in soil properties among the species and among sites within each species. This lack of differences might be due to the younger stage of the plantations.