Patterns of Leaf Litter Decomposition as Related to Litter Traits in the Sudano-Guinea Savannahs of Ngaoundere, Cameroon

Abstract

Litter decomposition processes are poorly studied in the savannahs. Leaf litter decomposition of the twenty-four contrasting plant species including trees, shrubs and grass species, was studied in the sudano-guinea savannahs of Ngaoundere, Cameroon. The litterbag technique was used to assess litter mass loss and single exponential model was adopted to estimate decay rate constants. Initial litter thickness varied from 0.02 to 1.11 mm, area from 4.27 to 245.89 mm2, sclerophyllous index from 0.01 to 1.75 mg.mm-2, density from 0.21 to 87.50 mg.mm-3, and specific mass area from 0.57 to 185.46 mm2.mg-1. Litter cellulose content varied from 3.79 to 11.84%; lignin from 2.84 to 8.12%, NDF from 21.35 to 80.41%, and total phenolic compounds from 0.47 to 17.76%. During the 52 weeks of the field experiment, mean dry mass remaining of litter samples was significantly between 8.05 and 75.22% of initial litter dry mass for C. papaya and C. regidus respectively. Litter decomposition rate constant (k) significantly ranged from 0.003 (C. regidus) to 0.121 %.week-1 (C. papaya). Litter mass remaining (LMR) was positively related to thickness (R2 = 0.605, P<0.01), Sclerophyllous index (R2 = 0.446, P<0.05), Specific mass area (R2 = 0.569, P<0.001), lignin (R2 = 0.631, P<0.01) and phenolic compounds (R2 = 0.618, P<0.001). The litter decomposition rate constant (k) was negatively related to thickness (R2 = 0.602, P<0.01, n=12), Sclerophyllous index (0.542; P<0.05), Specific mass area (0.419; P<0.05) and phenolic compounds (0.530; P<0.01). It can be concluded that litter decomposition is affected by plant species diversity, plant groups and physico-chemical traits of litters in the sudano-guinea savannahs of Ngaoundere, Cameroun. These preliminary results would contribute to understanding the mechanism of litter decomposition in general and in these savannahs in particular.