Aboveground Phytomass Dynamics in Grassland Steppe of Patagonia, Argentina

DEFOSSÉ, G. E.; BERTILLER, M. B. ; ARES, J. O.

JOURNAL OF RANGE MANAGEMENT

Society For Range Management

Lugar: Lakewood; Año: 1990 vol. 43 p. 157 - 160

0022-409X

Aerial and litter dynamics of a grassland steppe in Patagonia, Argentina, were studied at either monthly or bimonthly intervals for 2 years. This area is characterized by a cold and wet winter (June to September) and a warm and dry summer (Decembre to March). The growing season extends from September to April, with moist spring and fall interrupted by a mid-summer drought.  Festuca pallescens (St. Yves) Parodi  produced about 95% of the total annual phytomass.  Peaks of green phytomass were recorded in spring-summer of the first growing season (33.6 ±2.9 g m-2) and in early spring (35.0 ±2.4 g m-2) and fall (32.7 ±2.7 g m-2) of the second growing season. Less abundant forage grasses were Poa ligularis  Nees ap Steudel, Bromus setifolius Presl., Hordeum comosum Presl. And Rytidosperma virescens (Desvaux ) Nicora.  Shrubs and forbs represented less than 2% of the total annual phytomass of this grassland.  The relationships between phytomass production of the main species and some environmental variables are discussed.  These results contribute to the knowledge of aboveground phytomass dynamics and forage availability throughout the seasons of this grassland in Patagonia, and are part of the data necessary for proper range management planning.  This information will permit the designing of appropriate grazing schedules by balancing the number of grazing animals to the forage resources available.