Litter production and decomposition studies in selected species of acacia

Abstract

An experiment was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur during the period from 1999-2001 to study the litter production, nutrient return, litter decomposition and nutrient release pattern of three species of acacia viz., Acacia mangium Wild., Acacia aulacocarpa A. Cunn. ex Benth. and Acacia crassicarpa A. Cunn. ex Benth.

Litter fall of the three species followed a monomodal distribution pattern with a distinct peak in December for the three species. Nutrient return through different components of litter indicated that for the three species, leaf litter returned maximum quantity of all nutrients. The three species returned maximum amount of nitrogen when compared to potassium and phosphorus. A characteristic biphasic pattern of biomass decomposition was observed with a rapid initial phase followed by slow latter phase. Negative linear relationship between lignin concentration and rate of mass loss was evident for the three species in two study situations. Only a poor correlation between weather parameters and rate of decomposition was observed. Fluctuation in the nitrogen and phosphorous concentration of residual mass of the three species under different study situation was evident during the course of study. Potassium concentration for different species under various study situations was found to decline drastically during different months. The nitrogen, phosphorous and potassium mineralisation pattern of the three species of acacia under two study situations showed a best fit with the second order hyperbolic function.