ABOVE-GROUND PHYTOMASS DYNAMICS IN A GRASSLAND STEPPE OF PATAGONIA, ARGENTINA

The growing season extends from September-April, with moist spring and fall periods interrupted by a mid-summer drought. Festuca pallescens produced about 95% of the total annual phytomass. Peaks of green phytomass were recorded in spring-summer of the 1st 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 m-2) of the 2nd growing season. Less abundant forage grasses were Poa ligularis, Bromus setifolius, Hordeum comosum and Rytidosperma virescens. Shrubs and forbs represented <2% of the total annual phytomass of this grassland. The relationships between phytomass production of the main species and some environmental variables are discussed. -from Authors