Doctoral Dissertations

Orcid ID

https://orcid.org/ 0009-0007-9124-9854

Date of Award

8-2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Natural Resources

Major Professor

Patrick D. Keyser

Committee Members

Jennie Ivey, Virginia R. Sykes, Katie Mason

Abstract

Native pastures present an opportunity to diversify that can support an array of animals, including pollinators and livestock. A variety of insect pollinators, important for both crop production and wild fauna persistence, are in population decline and benefit from native floral resources to sustain across the landscape. The goals of our work were to document blooming and forage characteristics of a variety of native forbs and to determine their establishment, persistence, and forage characteristics under different grazing rest regimens. We also sought to measure animal productivity between grass and diversified pastures under continuous stocking. Forbs established and persisted differently based on life history characteristics, competitive advantages, and grazing preference. During all three trials, black-eyed Susan (Rudbeckia hirta L.; BESU), lanceleaf coreopsis (Coreopsis lanceolata L.; LCOR), purple coneflower (Echinacea purpurea (L.) Moench; PURC), oxeye sunflower (Helopsis helianthoides (L.) Sweet; OSUN), ticktrefoil (Desmodium (L.) DC.; TTFL), cup plant (Silphium perfoliatum L.; CUPP), and Maximilian sunflower (Helianthus maximiliani Schrad.; MSUN) were the most regularly observed species and demonstrated moderate to high establishment and persistence success. Of these species, LCOR, OSUN, and TTFL were grazed the most frequently by cattle (Bos taurus L.), and of these species both OSUN and TTFL showed the best persistence in pastures. Forb populations declined over multiple grazing seasons in both grazing trials; however, a combination of grazing and pasture rest appeared to develop the best persistence compared to long term grazing or rest. Forbs improved forage nutritive composition and stabilized crude protein levels throughout the season while reducing the concentration of fiber components later in the season compared to the maturing grass species. When combined with native warm-season grasses (NWSG), the forbs produced high quality forage that sustained cattle throughout the grazing season. Cattle produced higher overall ADG, and total bodyweight gain on pastures interseeded with forbs compared to NWSG alone, but animal days were most impacted by grazing management decisions and stocking density throughout the season. Overall, a blend of LCOR, OSUN, BESU, TTFL, PURC, CUPP, and MSUN could improve the diversity of NWSG pastures to support both cattle and critical pollinators.

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