Structure and Function of Oak Forests in Central Himalaya. II. Nutrient Dynamics

This paper elucidates nutrient dynamics in oak forests 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 32·4–98·0 %; 0·3–3·5 %, and 10·2–66·6 % of the total nutrients in the system. Considerable reductions (8·5–41·7%) in concentrations of nutrients in leaves 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 (above + below ground) to the soil by vegetation was 115·9–187 N, 7·5–15·6 P, 122·7–195·1 Ca, 36·1–48·8 K and 2·88–5·16 Na kg ha−1 yr−1. Turnover rate and turnover time for different nutrients ranged between 0·66–0·84 yr−1 and 1·19–1·56 yr−1, respectively. Compartment models for nutrient dynamics have been developed to represent the distribution of nutrient contents and net annual fluxes within the system.