Nutrients (N, P and K) dynamics associated with the leaf litter of two agroforestry tree species of Bangladesh

Eucalyptus camaldulensis (Dehnh.) and Swietenia macrophylla (King.) are not native to Bangladesh, but they are widely used in agroforestry practices for their commercial values. Selection of tree species with efficient return of nutrients is a vital challenge in agroforestry practices to maintain the soil fertility for sustainable crop production. Therefore, a comparative study was conducted on nutrients (N, P and K) leaching from leaf litter of E. camaldulensis and S. macrophylla in laboratory condition. The initial dry weight of leaf litter of E. camaldulensis and S. macrophylla were significantly (p < 0.05) decreased to 18% and 10%, respectively at the end of the experiment. Eucalyptus camaldulensis showed comparatively (t-test, p < 0.05) higher rate of weight loss, conductivity and TDS (Total Dissolved Solid) of leached water. Comparatively, higher amount of N (48 mu g g(-1)) was released from leaf litter of E. camaldulensis whereas higher amount of P (0.8 mu g g(-1)) and K (23 mg g(-1)) from S. macrophylla, leaf litter and both the species showed similar pattern of nutrient (K > N > P) release during the leaching process. Nutrients (N, P and K) concentration in leaf litter of these species showed significant (p < 0.05) negative exponential curvi-linear relationships with the weight loss. Results of this study suggests that E. camaldulensis is the best in terms of N return and S. macrophylla the best in terms of P and K return.