Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 58-63).

Thesis (M.S)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 172-178).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 71-74).

Thesis (Ph. D.) -- Lincoln University, 2007. / Also available via the World Wide Web.

This thesis investigates how small disturbances influence community structure in three permanent pastures. Small disturbances play an important role in providing spatial heterogeneity that permits new recruits to enter populations in closed sward communities, thereby promoting diversity and species co-existence. The thesis has four components: the first two are based on observation and measurement of the occurrence of small disturbances, molehills and dung pats, in three pastures. Within pasture seasonal changes in disturbance regime were related to changes in patterns of species abundance by multidimensional contingency table analysis. Dactylis glomerata, Agropyron repens and Taraxacum officinale increased in highly disturbed plots, whereas Holcus lanatus and Trifolium repens decreased. Invasion of molehills and dung pats was usually by rhizomes or stolons from surrounding plants. Seedling recruitment was rare: Trifolium repens was the only species dependent on small gaps for sexual regeneration. Patterns of species replacement on and around the disturbances were non-random. The third part of the thesis investigated the effects of selective removal of Lolium perenne, Holcus lanatus and Trifolium repens from the oldest and youngest pastures. Strong responses to the removal of these species were found only in grasses in the youngest pasture. This is consistent with the hypothesis that competition decreases over time because of niche divergence, but may also reflect biological accommodation to grazing pressure. The fourth part of the thesis investigated changes in species composition in simulated swards in response to different regimes of mowing, fertilizer and small gap creation. Species composition was strongly influenced by mowing and fertilization but was unresponsive to small gap creation. / Science, Faculty of / Botany, Department of / Graduate

No description available.

Dissertation (PhD (Agric))--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Call number: LD2668 .T4 1959 O38

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

Thesis (Ph. D.) -- Lincoln University, 2009. / Also available via the World Wide Web.