Organic Matter Production and Distribution of Nutrients in Plantations of Acacia mearnsii in Nilgiris, Tamil Nadu

Componentwise biomass production and the distribution of nutrients at the age of 4, 7 and 10 years of Acacia mearnsii plantation is presented. Linear regression analysis was carried out. Among the prediction variables tried, D²H was found to be the most reliable parameter for prediction purposes. The total above-ground biomass produced at 4, 7 and 10 years of age by class A was 20.4 t/ha, 27.1 t/ha and 151.4 t/ha; and 64 t/ha, 45.6 t/ha and 21.9 t/ha by class B respectively. Harvesting of utilizable biomass (wood. bark and branches) would result in the removal of 385 kg/ha (N), 4 kg/ha (P), 300 kg/ha (K), 205 kg/ha (Ca) and 50 kg/ha (Mg). Leaving leafand twig components at the site would not compensate the drain off. Some safeguard in terms of fertilization etc. is suggested, while raising the plantations of Acacia mearnsii.