Seasonal dynamics of nutrients in a Carex meadow

Abstract

Nutrient accumulation in aboveground biomass and mobilization of nutrients in litter were studied on a Carex meadow in southern Quebec, Canada. Seasonal changes were characterized by short periods of rapid element uptake and release. By late May the total element levels were 80% of maximum. Accumulation of N, P, and K was rapid relative to early increments in biomass. Ca, Mg, and micronutrients were taken up from the soil solution across the season and levels paralleled changes in biomass. In early summer elements were released from litter more rapidly than litter dry weight declined. Mobility of elements decreased in the order K > Mg > P > N > Ca. Overwinter, 83% of K was released, whereas Ca concentration in litter increased overwinter and through the following summer. Immobilization of Fe in litter was pronounced. Overall, > 90% of the element mass in green late-summer shoots was retained in litter overwinter.