Foliage Litter Decomposition of the Three Selected Indigenous Agroforestry Tree Species Jimma Zone Southwest Ethiopia

Abstract

Abstract In agroforestry land use system soil productivity is maintained through the decomposition of tree species biomass input mainly foliage’s litter material. The quality of foliage litter material could be considerably varied among species. Hence, better soil management decision in agroforestry land use system remains on identification and use of the desirable species biomass input based on their decomposition characters. A study was conducted to evaluate the decomposition pattern of foliage litter materials of three selected indigenous agroforestry tree species grown in Jimma town Boye nursery site, southwest Ethiopia. In the study single exponential model was employed to determine the decay rate of decomposing litter materials as the dependency of degradation rate on some litter chemical quality indices examined by using Pearson’s correlation coefficient. Results showed that, C.macrostachyus decomposed significantly faster than both F.vata and E.abyssinica with rate constant (k) of 0.0400 day− 1 (C. macrostachyus) and 0.0233 day− 1 for both F.vata and E.abyssinica with t respective 17.3 and 29.7days taken to loss 50% of original dry matter. The explained variation in rate of decomposition among the tested species was found to be due to the effects of some litter chemical quality parameters. Accordingly Cellulose and C/N ratio were identified as impeding biochemical parameters whereas Phosphorus and Nitrogen were identified as facilitators. Among the species, E.abyssinica reported to be the best species to return higher amount of nitrogen within a short time period followed by C.macrostachyus and F.vasta, respectively. The accelerated decomposition of C.macrostachyus may limit its potential for long-term build-up of soil fertility. Alternatively, E.abyssinica majorly and F.vasta in some cases should be considered for long-term build-up of soil organic carbon.