The Percent Ungrazed Plant (PUP) method estimates the percent of annual herbage production that is removed. The protocol involves counting the number of ungrazed perennial grasses and converting to percent utilization using an allometric equation. PUP was developed in spring 1950 at the Santa Rita Experimental Range (SRER) as a quicker, simpler substitute for height-weight estimates of utilization.  PUP is applied to an adaptive grazing management program on the SRER, but has not been tested with the widespread dominance of introduced lovegrass. We need to determine how the presence of Lehmann and Boer lovegrass (Eragrostis lehmanniana and E. curvula) influences PUP utilization estimates, and if utilization estimates vary between season of grazing (winter=January, February, March or spring=April, May, June). To examine these questions, utilization data were collected between 2010 and 2013 using two methods: PUP and utilization photo guides (PG).  PG is a more direct estimate of utilization that allows the observer to compare living plants to photographs with varying levels of utilization. PUP and PG methods were compared by year and by season. Across the year, PUP and PG were statistically different (p=0.004). For winter grazing, PUP and PG were different (p<0.0001), indicating the spring developed PUP differs with the cool season growth of lovegrass. With spring grazing, PUP and PG were not different (p=0.122), suggesting lovegrass has not changed the PUP relationship. Measuring utilization using PUP is recommended following spring grazing because it represents the end of the growing season making measurements more accurate and consistent than measurements following winter grazing.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.