Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

J. Earl Creech


J. Earl Creech


Blair L. Waldron


Dale R. ZoBell


Rhonda Miller


Tall fescue is the one of most common grasses in irrigated pastures throughout the Intermountain West. Two limitations of tall fescue are a decrease in productivity during hot summer months and the need for supplemental nitrogen (N). The objective of this research was to compare tall fescue-alfalfa (TF+ALF), tall fescue-birdsfoot trefoil (TF+BFT), tall fescue-nitrogen fertilizer (TF+N), and tall fescue without nitrogen fertilizer (TF-N) on forage yield, nutritional quality, and livestock performance. Research plots were established at the Utah State University Pasture Research Facility in Lewiston, UT in 2010 and grazed in 2012 and 2013. Treatments were arranged in a randomized design with four replications and divided into four paddocks per replication. Three Angus crossbred steers with an average starting weight of 380 kg were placed on each treatment and rotated to a new paddock every 7 days. A put-and-take method was used throughout the growing season such that each paddock received 80% utilization. Four forage samples were collected from each paddock just prior to grazing using a 0.5 m2 quadrat for determination of dry matter (DM) and nutrient content. ADF, NDF, IVTD, and TDN were used to estimate nutrient content and steers were weighed every 28 days to determine livestock performance. Tall fescue greatly benefits from added N whether via fertilizer or N transfer by legumes and this study showed that BFT and ALF mixed with TF increases plant and animal performance while reducing fertilizer costs and helps maintain a more environmentally sustainable pasture.