K. T. Osman , M. M. Rahman , P. Barua

Abstract

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.

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K. T. Osman , S. M. S. Haque , M. M. Rahman

Abstract

In the Keochia SiliviculturaI Research Station, Chittagong, Bangladesh, a semi-detailed soil survey was done in 1978. Afterwards plantations of Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis and Pinus caribaea were established. The soil were presently analysed for certain physico-chemical properties. It has been found that the organic matter, total N, available K and pH of soils have increased by the plantations.

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M. M. Rahman , M. W. Baksha , J. T. Sterringa

Abstract

This paper deals with the feeding behaviour of purple sunbird, Nectarinia asiatica. The bird eats the fruit of the mistletoes which are parasitic on gamar (Gmelina arborea) and teak (Tectona grandis) and helps in dispersal of mistletoe seeds in plantations of Bangladesh. When mistletoe fruits are not available in nature the bird is found sucking the nectar of an ornamental tree commonly know as Kolkaphul, Thevetia peruviana. The behaviour of the bird in relation to its alternate food sources was studied and discussed with a view to minimize dispersal of mistletoe seeds.

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