Oxygen Uptake and Nitrification by Soil Within a Grazed Atriplex vesicaria Community in Semiarid Rangeland

Abstract

The effect of plant distribution on oxygen uptake and nitrification in surface soil of a semiarid rangeland community was studied. Oxygen uptake and nitrification in surface (0-7.5 cm) soils from sites associated with Atriplex vesicaria bushes were at least twice as great as in soils from the interbush area. The pattern of nutrient cycling tended to reflect the distribution of plant material within the plant community. The effect did not extend to the 7.5-15 cm soil horizon. The rate of nitrification per unit total soil nitrogen was greater for the sites associated with saltbush than for the interbush area. These differences in rate of nitrification per unit total nitrogen persisted for at least two years following the total elimination of saltbush (Atriplex vesicaria) by heavy grazing.