Early summer grazing effects on defoliation and tiller demography of prairie sandreed
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CitationCullan, A. P., Reece, P. E., & Schacht, W. H. (1999). Early summer grazing effects on defoliation and tiller demography of prairie sandreed. Journal of Range Management, 52(5), 447-453.
PublisherSociety for Range Management
JournalJournal of Range Management
AbstractGrazing strategies should be designed to maintain vigorous populations of plant species critical for livestock production, wildlife habitat, and/or ecosystem functions. Treatments consisting of 5- to 7-day, mid-month grazing periods in June or July at 16, 32, or 48 animal unit days (AUD) per ha, were replicated 3 times and applied to the same pastures in 1995 and 1996 to quantify cattle use and tiller recruitment and mortality of prairie sandreed [Calamovilfa longifolia (Hook) Scribn.], a rhizomatous species characterized by dispersed populations of tillers. Cumulative grazing pressure (AUD Mg-1) was used to quantify treatments because of differences in phytomass among pastures and dates. Grazing pressure ranged from 10 to 90 AUD Mg-1 and accounted for 69, 61, and 77% of the variation in percentage of tillers grazed, mean defoliation of grazed tillers, and use of prairie sandreed, respectively. As grazing pressure increased from 10 AUD Mg-1, percentage of tillers grazed increased from 48 to 90%; defoliation of grazed tillers increased from 54 to 74%; and utilization of prairies and reed increased from 27 to 67% at plateaus beginning at 50 to 60 AUD Mg-1. When spring precipitation was above average, 45 to 55% use in June or July increased tiller densities, however, these increases were not sustained or repeated in the following year with average precipitation. Utilization was 50% at 28 AUD Mg-1 and 60% at 40 AUD Mg-1. Relatively large increases in utilization per-unit-change of grazing pressure below 20 AUD Mg-1 indicated that yearling cattle selectively grazed prairie sandreed. The high degree of correlation between percentage of prairie sandreed tillers grazed and use of prairie sandreed (R2= 0.91 in June and 0.90 in July) suggests that percentage of grazed tillers can be used to monitor early-summer use of this species in the Nebraska Sandhills.