Soil nitrogen availability under grasses of different palatability in a temperate semi-arid rangeland of central argentina

MORETTO A.S. ; R.A. DISTEL

AUSTRAL ECOLOGY

Wiley Blackwell

Año: 2002 vol. 27 p. 509 - 514

1442-9985

Grazing by domestic livestock is frequently associated with the replacement of high-nutrient palatable species with low-nutrient unpalatable species, which may have a substantial effect on nutrient cycling. The objective of the present study was to compare soil N availability and net N mineralization in soils under  Poa ligularis  (palatable grass) with those in soils under  Stipa tenuissima  (unpalatable grass) in a temperate semi-arid rangeland of central Argentina. Nitrogen availability and net mineralization under laboratory and eld conditions were measured. Soil N availability under  P. ligularis  was higher than or similar to soil N availability under  S. tenuissima . In situ  net N mineralization in the soil under  P. ligularis  was lower than or similar to net N mineralization in the soil under S. tenuissima . Potential net N mineralization was greater in the soil under  P. ligularis  than in the soil under  S. tenuissima . Our results suggest that the replacement of palatable grasses by unpalatable grasses in the temperate semi-arid rangelands of central Argentina may imply a reduction in the rate of nutrient cycling.