Evaluation of Fertilizer on Pronghorn Winter Range in Alberta

Abstract

Nitrogen (N) alone, and in combination with phosphorus (P), was applied to sagebrush (Artemisia cana)-grassland vegetation which formed part of a traditional winter range for pronghorns (Antilocapra americana) in southeastern Alberta. Fertilizer was applied once, in April of 1975, and forage quality, forage production, and pronghorn response were monitored for the next three growing seasons. Forage quality on fertilized plots increased initially, but by late summer of each year, nutritional content was essentially similar in fertilized and control areas. Forage production increased markedly in each of the 3 years. The application of P in addition to N had little impact on forage quality and production. In year two and three following fertilizer treatment, N levels of 84, 168, and 252 kg/ha resulted in progressively more forage produced with each increase in N. Pronghorns selectively utilized the fertilized plots more heavily than adjacent control areas. The inability to increase protein content in cured samples of sagebrush and pasture sage through fertilizer treatment detracts from the value of this procedure for improving pronghorn winter ranges. The general increases in total forage production and hence total protein production and the preference of pronghorns for treated areas, however, suggest that the procedure should be evaluated further.