Nutritional parameters for assessing pasture condition in the semiarid rangelands of Argentina

Abstract

Range condition is usually estimated from the palatability and ecological attributes of rangeland species. The aim of this research was to assess whether the inclusion of nutritional parameters improves the estimation of range condition in the semiarid Prosopis caldenia Burk rangeland of La Pampa, Argentina. Plots (24 ha) containing rangeland in different condition (fair and good) were grazed at low stocking rates during fall, winter and spring of two successive years. The aerial biomass (kg DM ha-1), in vitro dry matter digestibility (IVDMD) and crude protein content (% CP) of monthly samples of each species were determined. The percentage of total biomass (% TB) and % CP were estimated for each of six IVDMD ranks. In both years, and across nearly all IVDMD ranks, the % TB was different (p < 0.05) for the two range conditions, though % CP was similar (p > 0.05). The carrying capacity of good rangeland was 2.5 times greater than that of fair one when total aerial biomass and expected animal performance were similar. Taking nutritional parameters into account improves estimates of range condition in P. caldenia rangeland.