Forestry and Environment Sympoisum 1998, Sri Lanka

Fourth Annual Symposium organized by Department of Forestry and Environment Science, University of Sri Jayewardenapura, Sri Lanka.

Thursday, October 05, 2006

CHEMISTRY OF LEAF LITTER OF SOME AGRO-FORESTRY SPECIES IN SRI LANKA

M K T K Amarasinghe and R Senaratne
Faculty of Agriculture, University of Ruhuna.


Decomposition of leaf litter is a major process in the nutrient dynamics agroecosystems, which is intrically governed by the litter chemistry. The chemistry of leaf litter determines both the time course of decomposition and the nutrient release pattern. There are many agroforcstry species in Sri Lanka, but information available on their litter chemistry is scanty. Such information proves useful in identifying appropriate agro forestry species for developing sustainable agroeosystcms. Therefore studies were carried out to determine the concentrations of nutrients (% N, P, K, Ca and Mg), lignin and cellulose of nine agroforestry species in Sri Lanka, viz., Acacia auriculiforrnis, Acacia mangium,, Gliricidia sepium, Macaranga peltata (Kande), Alstonia scholaris (Alstonia), Artocarpus inrtegrifolia (jak), Artocarpus altilis (bread fruit), Terminallia cattappa (Indian almond), and Mangifera indica (mango).

Considerable interspecific variation in the above parameters was observed in tile leaf litter. As regards the per cents of N, P, K, Ca and Mg, the values observed varied from (1.395 - 1.921, 0.025 - 0.171, 016 - 0.95, 1.76 - 2.57 and 0.22 - 0.51, respectively. The highest concentration of N was in G. sepium while A. altilis, A. integrifolia and A. schoars had the highest concentration of P, K, Ca and Mg, respectively. This underlines the importance of introducing diverse species (biological diversity) in order to establish a balanced fertility regime. M. indica and A. mangium had the highest concentration or lignin (22.99 %) and cellulose (32.76%), respectively. A salient feature in the leaf litter in M. indica was that, it had the lowest concentration of N (0.395 %) and cellulose (14.59 %) and the highest concentration of lignin (22.99%). These data prove useful in identifying a suitable combination of agroforestry species for sustainable soil fertility management.

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