Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2000
Publication Date: N/A
Citation: N/A Interpretive Summary: Forbs and shrubs can play important roles in plant communities of the Nebraska Sand Hills. They make up most of the list of plant species for the area, and produce plant materials of high, but variable quality. However, forbs and shrubs produce low levels of standing crop, and many are rare. As such, their use by cattle is not fully understood. Utilization of this part of the plant community must be described to ensure proper management, as some species of forbs are indicators of proper (or improper) grazing. A study was undertaken to examine the density (plant number per unit area) of 5 key species and 7 groups of less-common forbs and shrubs, and how they were used by yearling cattle grazing small experimental pastures (2:5 acres), on the University of Nebraska, Gudmundsen Sandhills Laboratory during 1989-1991. In this study, forbs and shrubs represented only 9% of all plants in the pastures, and just 14% of production. Fifty- six species of forbs and shrubs were recorded during the study, which was 76% of all species noted. Sand Hills forbs and shrubs were found to be of variable value to yearling cattle. Some species and species groups were more heavily grazed when production was low, as during drought years or early in the growing season. Others were grazed more heavily at specific times of the growing season, or during years when a particular species or group was more common. Value of Sand Hills forbs and shrubs to cattle appears to depend on the quality of the forage produced by the different species, stage of maturity of plants, and the overall level of production of the plant community.
Technical Abstract: Forbs and shrubs are important to species richness in Sand Hills plant communities, and many species produce high quality herbage. However, levels of standing crop tend to be low, and utilization of forbs by cattle grazing Sand Hill range has not been fully quantified. Density and use (percent of plants grazed) of 5 dominant species (green sagewort, slender greenthread, stiff sunflower, western ragweed), and 7 groups of less-commo species (cacti, gromwells, legumes,other perennial asters, other perennial forbs, annual forbs, and shrubs) were studied during 1989-91 at the University of Nebraska, Gudmundsen Sandhills Laboratory. Data were collected within 3 replicates of 4-6 day single use grazing periods (removing 1.4 AUM/ha of forage) applied to one ha paddocks in mid-June, July and August. Data were collected from fifty, 1.0 m**2 circular quadrats per paddock, and analyzed as a split-plot in time. Sand Hills forbs appeared to be of variable value to yearling cattle. Utilization of western ragweed, green sagewort and legumes (8 species) was highest when standing crop was limited (during drought years and early growing season). Utilization of skeletonweed and other perennial forbs (12 species) was variable during the growing season; skeletonweed was more heavily grazed in June and August, while the other perennial forb class was utilized more during July. Annuals and biennial species were grazed most heavily during drought years, and use declined with advance of the growing season. Utilization of forbs and shrubs of the Nebraska Sand Hills would appear to be dependant on forage quantity and quality of the different species, stage of plant maturity, and overall productivity of the plant community.