Abstract

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There is high demand for nutrients by exotic tree species due to their rapid growth rate. The decomposition of leaf litters of two plant species, Tectona grandis and Eucalyptus camaldulensis were investigated using litterbag study. Soil and leaf litters were collected from six sampling sites in each plantation designated as El - E6 for E. camaldulensis and Tl - T6 for T. grandis respectively. The collected samples were analyzed for their chemical properties using standard methods at day 1, 30 and 60 during the experimental period. Results showed that the decomposition rate in E. camaldulensis ranged from 0.00271 to 0.00571 while in T. grandis, decomposition rates ranged from 0.00824 to 0.01527. There was a general decrease in both foliar mass and chemical compositions while soil chemical and microbiological parameters increased, indicating nutrient release into the soil. Decomposition rates was higher in T. grandis than E. camaldulensis with ranges of 0.00824 - 0.01527 day"1 and 0.00271 - 0.00571 day" 'respectively, possibly due to the hard texture and waxy coating of E. camaldulensis. Significant difference was observed in their decomposition rates with a F-Value of 0.001. due to the difference in their s~il chemical properties. Carbon (IV) oxide evolution was highest on day 30 in both species. Analysis of variance revealed that soil carbon, carbon (IV) oxide evolution, pH, potassium and magnesium were significantly different between the sampling sites of each plantation. It is concluded from this study that site conditions determine to a large extent, the decomposition rate of leaf litter samples

Keywords: Decomposition, leaf litters, soil. rate, microbiological, chemical