Resumen

BERTOLAMI, Miguel A.; RUETER, B. I.  y  BENITEZ, M. E.. Forage production estimation model through pastoral value in the southeast of Chubut province, Argentina. Multequina [online]. 2005, vol.14, n.1, pp.29-38. ISSN 1852-7329.

Getting to know the forage available in arid ecosystems is one of the basic problems at the moment of make an assessment of Patagonian grasslands. The aim of this work was the adjustment to the forage production estimation model through pastoral value in two ecosystems in the southeast of Department Escalante (Chubut province). The analyzed ecosystems belong to different ecologic areas, one of them corresponds to herbaceous steppes of Festuca pallescens, Festuca argentina, Poa ligularis with Adesmia volkmanii, Senecio filaginoides and Verbena sp shrubs to Golfo San Jorge Distric, meanwhile, the other one is located in Central District, Chubutense Subdistrict (Soriano, 1956) is a dwarfs shrubs steppe of Nassauvia glomerulosa y N. ulicina with Poa dusenii grasses. The samples have been made in exclousures to ovine grassing in Pampa de Salamanca (Golfo San Jorge District) and in Pampa Vaca (Central District). The forage biomass was determined from seasonal crops clipping aboveground material with 0,2 m ² frames. The forage PPNA was estimated following the methodology of Singh et al (1975), for the period 1990-1994. On the other hand, line transects have been made from which ones the pastoral values were obtained, for the period 1998-2001. Besides the time difference, the periods can be compared because their rain means are alike. A regression model was obtained for each ecosystem from which one is feasible estimate the forage PPNA from the VP. These models let assess different productive situations taking into account the structural and functional features of the ecosystem, as well as determine the stock capacity, with the corresponding use factor.

Palabras clave : Forage production; Pastoral value; Stock capacity; Arid lands; Patagonia.

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