Biomass trends in a Nebraska sedge meadow, Sierra national forest, California

Abstract

Nebraska sedge ( Carex nebraskensis Dewey) is an important forage species in meadows of the Western United States, but there is a lack of information about its management. Above-ground and below-ground biomass trends were studied within a livestock exclosure on a Nebraska sedge meadow site in Tule Meadow, Sierra National Forest, California. Standing crop, litter and soil samples were collected at 2-week intervals from early spring to late autumn in 1980 and 1981. Above ground standing crops are maximum (474 g m −2) when seeds are ripening. Net primary production averaged 405 g m −2 year −1. Standing live biomass is also maximum (306 g m −2) at seed ripening. Standing dead biomass and litter biomass are both maximum at senescence (378 g m −2 and 1155 g m −2, respectively). Little standing dead biomass flows to the litter layer until snow compacts the vegetation. High amounts of litter in autumn result from rooth growth. As above-ground growth accelerates, below-ground biomass declines. It increases during flowering, dips as seeds ripen and is maximum (30 g dm −3) in autumn. Below-ground production averaged 24 g dm −3 year −1. Nitrogen concenrations in standing crops, litter and the soil, and phosphorus and potassium concentrations in the soil are discussed.