The Structure and Function of Pine Forest in Central Himalaya. II Nutrient Dynamics

This paper elucidates nutrient dynamics in a pine forest, previouslyinvestigated for dry matter dynamics. The nutrient concentrationsin different life forms were of the order: herb > shrub >tree whereas the standing state of nutrients were of the order:tree > shrub > herb. Soil, litter and vegetation respectivelyaccounted for 38·1–82·2, 2·4–3·7and 15·4–58·2 per cent of the total nutrientsin the system. Considerable reductions (52–69 per cent)in concentrations of nutrient in needles occurred during senescence.The uptake of nutrients by vegetation, and also by differentcomponents with and without adjustment for internal recycling,has been calculated separately. Annual transfer of litter tothe soil by vegetation was 76·21 N, 6·25 P, 57·24Ca, 14·22 Mg, 19·92 K and 1·92 kg ha^–1Na. Turnover rate and turnover time for different nutrientsranged between 0·40–0·64 and 1·56–2·50year, respectively. Compartment models for nutrient dynamicshave been developed to represent the distribution of nutrientcontents and net annual fluxes within the system. Nutrient concentration, standing state, uptake, internal recycling, nutrient return, turnover, nutrient cycling