Leaf litter decomposition and nutrient release of three selected agroforestry tree species

Investigation was carried out on leaf litter decomposition and nutrient content of three agroforestry species—Annona muricata L., Senna siamea (Lam.) and Cola nitida (Vent.) using litterbag technique. Oven-dry leaf litters of each species were put in 432 litterbags of 23 g each. These were divided into two sets with one placed on the soil surface (SSP) and another, soil incorporated (SIP). Initial nutrient content (INC), decay constant, half- and full-lives (weeks) were determined. Decomposition rates, nutrient release patterns (NRP) and litter quality were measured fortnightly for 24 weeks after litter placement (WALP). Data collected were subjected to descriptive statistics and ANOVA at α0.05. The INC was significantly different among the species. N concentration decreased from C. nitida A. muricataS. siamea. P was significantly higher in S. siamea (0.38%) than C. nitida (0.22%) and A. muricata (0.32%). Decay constant was highest (0.005) in C. nitida under SIP. Highest half-life (49.5 weeks) and full-life (178.57 weeks) were recorded in S. siamea and C. nitida; and S. siamea and C. nitida under SSP. After 24 weeks, C. nitida had the highest decomposition rate, 5.97 ± 0.0 under SIP. NRP showed that A. muricata and S. siamea had the highest P (0.17%) and cellulose (28.2%) at 24 WALP under SIP. Lignin concentration at 24 WALP was highest in S. siamea (4.35%) and least in C. nitida (0.43%). Decomposition trend and nutrient release pattern from the leaf litters of selected agroforestry species indicated the potential of these leaf litters to offer nutrients on a sustainable basis in an agroforestry system.