Nutrient content and decomposition of leaf biomass of selected woody tree species

Abstract

A detailed study was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1992-94 to compare the rate of decomposition and nutrient release pattern of leaf biomass of five forest tree species namely, Schleichera oleosa (Lour.) Oken, Pongamia pinnata (L.) Pierre, Macaranga peltata, (Roxb) M.–A., Terminalisa paniculata Roth and Bridelia retusa (L.) spreng. The experiment was laid out in a typical home Garden. Generally, all the species under study showed a faster rate of leaf biomass decomposition. Among the various species tested, B. retusa and T. paniculata showed faster rates of leaf biomass decomposition while P. pinnata exhibited relatively a slower rate. The initial leaf nitrogen content and C:N ratio could not establish a direct relationship with rate of decomposition. However, in all the species, lignin content was found to exert a profound influence on mass loss patterns. All the species showed a faster mineralisation of nutrients in accordance with the mass loss pattern. Among the nutrients, potassium followed a faster rate of mineralisation. A relatively good trend for N mineralisation also has been reported for M. peltata, T. paniculata and B. retusa during the course of the study. Generally, Ca, Mg and S exhibited lower rates of mineralisation. T. paniculata and B. retusa followed an efficient release pattern for all the nutrients while P. pinnata showed slower rates of mineralisation with regard to most of the nutrients.