Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica,Dalbergia sissoo, and Melia azedarach) of Bangladesh

Azadirachta indica A. Juss, Dalbergia sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag technique to assess the nutrient return efficiency of these species. The decomposition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant (p<0.05) positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach (6.67). Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release (K > N > P) during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.