Studies were conducted on Heteropogon contortus at three natural stands and a common nursery in southeast Arizona and under controlled conditions. The objective was to examine H. contortus growth and development and relate it to concurrently measured environmental variables, especially soil temperature. It was hypothesized that response to such environment variables would be sufficiently consistent to serve as an indicator of range site characteristics. Response to temperature of local accessions was examined under controlled conditions to confirm field observations and determine the possibility of ecotypic differences. Common nursery studies examined phenotypic response of local accessions plus others from outside the region, to examine ecotypic response. Major conclusions were that H. contortus distribution pattern varies among sites of different temperature and/or moisture regime. Sites where H. contortus is prominent have definite characteristics, associated with warm microsites at high elevations (southern aspects, increasing slope) and mesic microsites at low elevations (the borders of washes, roadsides or microdepressions). Growth was entirely associated with the current year, with no carry-over of vegetative tillers from previous years. Growth began in spring, but was soon restricted by depleted soil moisture. Major growth, flowering and seedling establishment occurred during summer rains. Growth ceased with the first frost. Seedling survival appeared temperature dependent at high elevations, extreme temperatures perhaps responsible for age structure differences among sites. Overall growth and development and microsite requirements appear sufficiently consistent for H. contortus presence and growth pattern to indicate range site characteristics, especially temperature. The response to temperature of H. contortus is typical of C4 species, the temperature threshold for leaf elongation being approximately 15 C. However, carry-over effects of cold nights together with warm days may reduce elongation. There is little ecotypic difference in response to temperature among local accessions. However, non-local material differs in cold tolerance (both more or less tolerant) and flowering date from local accessions. Some accessions may be more valuable for early-season growth than local accessions if H. contortus establishment is considered.

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Master of Science / Department of Animal Sciences and Industry / Barry J. Bradford / Declining ground water supplies are putting significant pressure on the dairy industry in the United States. The water needed for forage production represents the great majority of total water use on most dairy farms, posing a major challenge in the pursuit of improved drought resilience. Teff (Eragrostis tef), a drought-tolerant annual grass (C4 physiology) native to Ethiopia, could prove an attractive alternative to traditional forage crops. While teff grass has potential to fit the needs for forage production in water-stressed regions, very little is currently known about its nutritional characteristics and whether it can support high levels of milk production by dairy cattle. An experiment was conducted to investigate the effects of variety and cutting age on dry matter yield, nutritive values, and digestibility of teff grass. Eighty pots were blocked by location in a greenhouse and randomly assigned to 4 teff varieties (Tiffany, Moxie, Corvallis, and Dessie) and to 5 cutting ages (40, 45, 50, 55, or 60 d after planting [DAP]). Results from this study indicate that, under greenhouse conditions, the first cutting of teff grass should be harvested at 45 to 50 DAP to optimize forage yield, quality, and digestibility in that cutting and in subsequent cuttings. A second experiment was conducted to assess the productivity of lactating dairy cows fed diets with teff hay as the sole forage. Nine multiparous Holstein cows were randomly assigned treatment sequence in a 3 × 3 Latin square design. Diets were either a control, where dietary forage consisted of a combination of corn silage, alfalfa hay, and prairie hay, or 1 of 2 teff diets, where teff hay was the sole forage. The teff diets maintained yields of milk and milk fat while increasing milk protein yield. Together, these two studies suggest that teff-based diets have potential to maintain high levels of milk production while improving the resilience of the dairy industry to future water shortages.

Student Number : 9812661N - MA dissertation - School of Art - Faculty of Humanities / This research focuses on change and the effects of economic development on the design and production of the traditional grass mat made by women in Swaziland. The visual quality of the traditional Swazi grass mat has transformed. The mat making technique remains unchanged, as does the main raw material in the construction of the mat, but now the traditional grass is accompanied by an artificial element: sweet wrappers, creating shimmering new designs. The technology of making grass mats has been revolutionised with the introduction of the Imbongolo mat-making frame. These changes represent an example of a dynamic art form in the context of the deep-rooted tradition of Swazi material culture. Through interviews with a number of mat-makers and a comprehensive collection of mat samples gathered over an extended period these modifications have been recorded and evaluated in terms of the producers’ response to economic constraints, and the availability of new plastic materials.

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No-till pasture renovation can increase the quality and forage yield of underproductive pastures. Decreased erosion, lower costs, and less lost grazing time are advantages of no-till renovation compared to conventional renovation. Unwanted vegetation is first controlled with herbicides to decrease competition for introduced orchardgrass. Two field trials were conducted using a split-plot design to compare three seeding methods and two herbicides. An Aerway no-till drill, a Tye double disk drill, and broadcast followed by harrowing were the seeding methods. Paraquat and glyphosate were used to determine herbicide effect on vegetation control. Orchardgrass did not adequately survive at either trial site. However, where some orchardgrass did survive, vegetation control was more important than seeding method. Competition from annual grasses, many germinating after herbicides were applied, was the reason for renovation failure. Herbicide and initial growth for best control. Yield was doubled in the first harvest by the addition of fertilizer. Early spring forage production from poor pastures is usually more than adequate, so the increase from fertilizer is of marginal value unless it is stored for later use. Yield increase did not carry over to the second harvest when it could be better utilized. Later application dates would extend yield increases from certain species if water is available. / Graduation date: 1994