Determination of leaf litter input, quality, and decomposition rates in young Nauclea diderrichii and Terminalia superba plantations in Nigeria

Abstract

Using litter traps and a litterbag experiment, the input, decomposition rates and changes in chemical characteristics of leaf litter were evaluated in seven-year-old Nauclea diderrichii and Terminalia superba plantations in Nigeria. Four plots (25 m by 25 m) were laid in the Nauclea diderrichii plantation, while three (25 m by 25 m) were laid in the Terminalia superba plantation. One litter trap was placed in each plot, while 30 litterbags containing leaf litter of each species were randomly placed in each plantation for 80 days. Litter input per month, leaf litter weight loss, nitrogen, organic carbon, phosphorus, lignin, polyphenol contents, C:N and lignin: N ratios of the litter samples were determined. After four months, there was no significant difference in the monthly litter input to each plantation. However, monthly litter input was higher in Nauclea stand (549.21kg ha^-1) than Terminalia (109.02 kg ha^-1). After 80 days, 39.81% and 54.15% of leaf litter weight was remaining for Terminalia superba and Nauclea diderrichii, respectively. The single exponential decay constants were 0.0093 day^-1 (Nauclea diderrichii) and 0.0096 day^-1 (Terminalia superba). As decomposition progressed, nitrogen, phosphorus, organic carbon, lignin and polyphenols varied differently for the two species. Phosphorus and C: N ratio increased with time of decomposition for both species. However, the C: N ratio of Terminalia leaf litter had a sudden decrease after 80 days, suggesting mineralization of the leaf litter.