Leaf Litter Decomposition and Nutrient Release from Cordia Africana Lam. and Croton Macrostachyus Del. Tree Species

Abstract

The objective of this study was to investigate the nutrient content of abscised leaves of Cordia africana Lam. and Croton macrostachyus Del. tree species and the extent to which they decompose to release these nutrients. Abscised leaves were collected from trees of these species and were evaluated by litter-bag technique for a period of 3 months. Nutrient return from each selected species showed that leaf of C. macrostachyus had significantly higher (P < 0.05) P but lower C compared with the leaf of C. africana. N concentration in the leaf of the study species did not show significant variation. Leaves of C. africana had significantly (P < 0.05) higher concentration of lignin and significantly higher lignin:N and C:N than C. macrostachyus. C. macrostachyus showed more rapid mass loss and nutrient release than C. africana. 50% of the biomass applied was lost during the first 6-7 weeks in C. macrostachyus and 9-10 weeks in C. africana. The half lives of N and P were 6-7 and 8-9 weeks, respectively, in C. macrostachyus. In C. africana, however, the half-lives were 13-14 and about 19 weeks for N and P, respectively. Generally, leaves with higher initial lignin, lignin:N and C:N ratios had lower decomposition and mineralization rates.

Key words: Cordia africana, Croton macrostachyus, litter, decomposition, nutrient.