T. Montani et al., PRODUCTION AND NITROGEN CYCLING IN AN ECOSYSTEM OF ERAGROSTIS-CURVULAIN SEMIARID ARGENTINA .1. PLANT BIOMASS AND PRODUCTIVITY, Acta oecologica, 17(2), 1996, pp. 151-162
The seasonal changes in aboveground and belowground biomass and produc
tivity were studied in Eragrostis curvula (Schrad.) Nees, an important
perennial tussock grass in semiarid Argentina. Aboveground material w
as separated into live and dead shoots or inflorescences, and litter.
Roots were taken up to 1 m soil depth using 25 cm increments, and clas
sified as dead or alive. Live shoots contributed most (>50%) to the to
tal aboveground biomass from early spring to early autumn, and represe
nted 10% of foliage during winter. Inflorescences were a small fractio
n (less than or equal to 2%) of total aboveground production which rea
ched a maximum of 6418 kg ha(-1). This value was 7% lower than total a
boveground annual net productivity (6908 kg ha(-1) yr(-1)). Live and d
ead roots had similar biomasses at each soil depth, and values ranged
from 4480 (0-25 cm) to 270 (75-100 cm) kg ha(-1) Maximum total belowgr
ound biomass (11200 kg ha(-1)) was 15.3% lower than total belowground
annual net productivity (13226 kg ha(-1) yr(-1)). Biomasses of live or
dead roots, and belowground net productivity decreased with increases
in soil depth. Ratios of total belowground to aboveground biomasses w
ere >1. This may represent a survival strategy for E. curvula when gro
wing under arid and semiarid conditions.