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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Legume Establishment in Native Warm-Season Grass Pastures

Phillips, Carter Bradley 18 December 2023 (has links)
Interseeding legumes in native warm-season grasses (NWSG) may improve the nutritive value of the stand, result in more consistent forage availability throughout the growing season, and increase forage yield. These benefits are often not realized due to difficulties in establishing legumes in existing NWSG stands. The objective of this study was to investigate the effect of planting method of legume interseeding, timing of legume interseeding, and the efficacy of burning plant residue on legume establishment in NWSG. Two forage legumes, 'Alice' white clover (Trifolium repens L.) and 'Freedom HR' red clover (Trifolium pratense L.), were interseeded into mixed 'Niagara' big bluestem (Andropogon gerardii Vitman), 'GA Ecotype' Indiangrass (Sorghastrum nutans Nash), and 'Camper' little bluestem (Schizachyrium scoparium) pasture in 2022 and 2023 at the Southern Piedmont AREC in Blackstone, Virginia. Planting method at three levels (no-till drill, broadcast, and non-planted control) were evaluated at three planting timing levels (fall planting, winter planting, and winter planting with burned residue). Among the treatment combinations, burned plots that were drilled resulted with the greatest spring clover count of 236 plants m-2, followed by winter drill (146 plants m-2) and burn broadcast (133 plants m-2). All fall plantings and all control plots were similar with a mean of 21 plants m-2. As a result of greater initial clover emergence, plots that were burned or seeded in the winter had greater clover content throughout the experiment; burned and drilled plots had over 90% clover ground cover throughout the second year. Domination of plots by clover in the second year caused yields and the proportion of NWSG in the stand to decline, with burned plots yielding 5,757 kg ha-1 compared to a winter-fall mean of 7,429 kg ha-1. Plots with greater clover content were able to sustain higher crude protein content and lower neutral detergent fiber content in both the establishment year and the second year. Though interseeding legumes benefitted nutritive values, these results suggest that red clover may be incompatible with the NWSG evaluated. Burned plots were especially affected by excessive competition. Further research is needed to evaluate forage legume species which complement NWSG in mixture rather than compete with them. / Master of Science / Interseeding legumes in native warm-season grasses (NWSG) may improve the nutritive value of the stand, result in more consistent forage availability throughout the growing season, and increase forage yield. These benefits are often not realized due to difficulties in establishing legumes in existing NWSG stands. The objective of this study was to investigate the effect of planting method of legume interseeding, timing of legume interseeding, and the efficacy of burning residue on legume establishment in NWSG. Two forage legumes, 'Alice' white clover (Trifolium repens L.) and 'Freedom HR' red clover (Trifolium pratense L.), were interseeded into mixed 'Niagara' big bluestem (Andropogon gerardii Vitman), 'GA Ecotype' Indiangrass (Sorghastrum nutans Nash), and 'Camper' little bluestem (Schizachyrium scoparium) pasture in 2022 and 2023 at the Southern Piedmont AREC in Blackstone, Virginia. Planting method at three levels (no-till drill, broadcast, and non-planted control) were evaluated at three planting timing levels (fall planting, winter planting, and winter planting with burned residue). Among the treatment combinations, burned and drilled plots produced more clover plants in spring at 236 plants m-2, followed by winter drill (146 plants m-2) and burn broadcast (133 plants m-2). All fall plantings and all control plots were similar with a mean of 21 plants m-2. As a result of greater initial clover emergence, plots that were burned or seeded in the winter had greater clover content throughout the experiment; burned and drilled plots had over 90% clover ground cover throughout the second year. Domination of plots by clover in the second year caused yields and the proportion of NWSG in the stand to decline, with burned plots yielding 5,757 kg ha-1 compared to a winter-fall mean of 7,429 kg ha-1. Plots with greater clover content were able to sustain higher crude protein content and lower neutral detergent fiber content in both the establishment year and the second year. Though interseeding legumes benefitted nutritive values, these results suggest that red clover may be incompatible with the NWSG which were evaluated. Burned plots were especially affected by excessive competition. Further research is needed to evaluate forage legume species which complement NWSG in mixture rather than compete with them.
2

Can Beef Be Bee-Friendly?  Using Native Warm-Season Grasses and Wildflowers in Pastures to Conserve Bees

Wagner, Jennie Faith 29 May 2020 (has links)
Over the past several decades, native and managed bee populations have decreased in the United States and worldwide. Although bee decline is attributable to several factors, habitat loss is the primary driver. Simultaneously, cattle producers in the eastern U.S. rely primarily on cool-season forages that peak in biomass production in late spring, leading to a lack of forage in the summer months and increasing the costs of cattle production. Seeding pastures with a mix of native warm-season grasses and native wildflowers could increase forage availability while also increasing available resources for bees. In this study, a mix of three native warm-season grasses (NWSGs) and 15 wildflower species was planted at the Virginia Tech Shenandoah Valley Agricultural Research and Extension Center (SVAREC). The objectives of this project were to document the establishment and species composition of NWSG + wildflower pasture mixtures, compare the attractiveness of wildflowers and weedy species to bees, and compare the bee community between NWSG + wildflower pastures and more typical cool-season grass pastures. The wildflowers in the NWSG + wildflower pastures dominated over grasses. All wildflower species that established were attractive to bees, as were some weedy species. The NWSG + wildflower treatments had the highest abundance of bees collected, with an average of 14.8 bees collected per pasture per sampling date in 2018, and an average of 12.4 bees collected per pasture per sampling date in 2019. These results indicate that with modification of establishment methods so that more grasses are present, this pasture system could be beneficial from both a cattle production and bee conservation standpoint. / Master of Science in Life Sciences / Over the past several decades, there has been a decline in bee populations in the U.S. and around the world. Bees play an important role in pollinating many food crops, including most fruits and vegetables. Habitat loss is the biggest contributor to their decline. There are also issues with cattle production in the eastern U.S. Most farmers rely on grasses that are the most productive in the late spring and early summer, meaning that by mid- and late summer, there is little grass available for cattle. Planting pastures with native grasses designed to be the most productive in the late summer and native wildflowers could increase food available for cattle as well as provide more pollen and nectar for bees. In this experiment, we planted a mix of three grasses and 15 wildflowers. We documented how well the grasses and wildflowers established. We also examined how attractive wildflowers and weeds were to bees and compared the number and types of bees collected between the new pastures and traditional pastures. We found that the wildflowers, instead of the grasses, dominated the pastures. All wildflowers that established, as well as some weeds, attracted bees and provided resources. Higher numbers of bees were collected in the pastures with wildflowers than standard grass pastures, but there were not necessarily more bee species present. These results suggest that, with some modifications, planting native grasses and wildflowers in pastures could help conserve bees as well as benefit cattle farmers.
3

Avian Response to Production Stands of Native Warm-Season Grasses in the Mid-South

West, Andrew Steven 01 August 2011 (has links)
Grassland birds have declined more than any other guild of birds in North America, largely due to loss and degradation of native grasslands. The Conservation Reserve Program (CRP) has restored some native warm-season grasses (NWSG), but grassland birds continued to decline (-1.1% annually) partly due to the limited acreage converted (1% of southeastern US). Using NWSG in production settings provides profit incentive to landowners while reducing dependency on government programs. Studies examining these production practices and their effect on grassland birds east of the Great Plains are limited. During 2009 – 2010, I surveyed 102 NWSG fields in Kentucky and Tennessee being used for production purposes (control, biofuel, seed, hay, and pasture treatments) to assess bird use and vegetation characteristics. Landscape cover around each field (250, 500, and 1000 m) was digitized from aerial photography. Using analysis of variance (ANOVA), I compared bird (relative abundance, species diversity, and species richness) and vegetation (average height, litter depth, vertical cover, litter cover, and vegetation cover) metrics across the five treatments. Relative abundance for all species, species diversity, and species richness were all greater for seed production fields (P <0.05); other treatments did not differ. Field sparrows (Spizella pusilla) were less abundant (P <0.05) in biofuel than control, hay and graze treatments, whereas eastern meadowlarks (Sturnella magna) and dickcissels (Spiza americana) were more abundant in seed fields. Average vegetation height, vertical cover, percent litter, percent forbs and percent woody plants differed (P <0.05) among treatments. Using Program Mark, I modeled occupancy for field sparrow, red-winged blackbird (Agelaius phoeniceus), eastern meadowlark, and northern bobwhite (Colinus virginianus) using vegetation and landscape cover as covariates. Treatment was influential in field sparrow and eastern meadowlark models, but not those for red-winged blackbird and northern bobwhite. Occupancy for field sparrow and northern bobwhite were affected by woody cover (+), for red-winged blackbird by vegetation height (-), and for eastern meadowlark by litter depth (+) or percent NWSG (+). All four species were negatively affected by forest within 250-m. Use of NWSG in production could increase the amount of available habitat and thus, help conservation efforts for grassland birds.
4

Restoring blackland prairies in Mississippi: remnant-restored prairie comparisons and techniques for augmenting forbs

Dailey, Andrew Clifford 13 December 2008 (has links)
One knowledge gap hindering prairie restoration is uncertainty about when a restored prairie communities sufficiently resemble remnant prairie. I surveyed plant communities in remnant prairies, prairies > 5 years post-restoration, and prairies ≤ 5 years post-restoration in Mississippi. Remnants had the greater species richness. Restored prairies had less cover of woody plants and forbs but greatest non-natives. Restored prairies were not similar to remnant prairies (similarity index = 28.9 - 25.9%), primarily because restored prairies had fewer prairie forbs. Thus, restoration may take decades. Transplanting locallyapted prairie forbs into restored prairies may accelerate restoration, but this has not been evaluated adequately. I transplanted a prairie forb (Liatris pycnostachya) into prepared beds, oldields, and restored prairies. Prepared beds had greater growth and seed production, but survival and flowering was high in oldields and restored prairies. Augmenting restored prairies with locallyapted forbs has promise for accelerating prairie restoration.

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