The structure and function of pine forest in Central Himalaya. II. Nutrient dynamics

Abstract

This paper elucidates nutrient dynamics in a pine forest, previously investigated for dry matter dynamics. The nutrient concentrations in 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 respectively accounted for 38·1-82·2, 2·4-3·7 and 15·4-58·2 per cent of the total nutrients in 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 different components with and without adjustment for internal recycling, has been calculated separately. Annual transfer of litter to the soil by vegetation was 76·21 N, 6·25 P, 57·24 Ca, 14·22 Mg, 19·92 K and 1·92 kg ha⁻¹ Na. Turnover rate and turnover time for different nutrients ranged between 0·40-0·64 and 1·56-2·50 year, respectively. Compartment models for nutrient dynamics have been developed to represent the distribution of nutrient contents and net annual fluxes within the system.