Thesis (M.S.)--Oregon State University, 1978. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [113-120]).

Thesis (Ph. D.)--Oregon State University, 1996. / Typescript (photocopy). Includes bibliographical references (leaves 150-160). Also available on the World Wide Web.

Interference among plants involves responses of plants to their environment as modified by the presence and/or growth of neighbouring plants. An important theme of research on plant interference is the relationship between plant population density and measures of plant growth or agricultural yield. An experiment on plant interference was performed in which plots of two important forage species, orchardgrass (Dactylis glomerata L.) and timothy (Phleum pratense L.), were grown at different total population densities and mixture proportions. Measures of plant growth and yield were taken at five separate harvests during one growing season. The analysis of variance indicated that primary and derived measures of growth and yield generally were strongly affected by the three main experimental factors: time, total population density and mixture proportions. Best subset multiple regression analysis, using Mallow's CP criterion, helped to define which experimental factors and interactions were related closely to plant responses. Both of these analytical methods indicated that the main effects of experimental factors were often significant, while interactions among factors were less prominent. The best subset models were different in structure for different response variates, however, indicating that plant responses varied when different measures of growth were considered. Models were developed which provided an effective description of yield-density responses in monocultures and mixtures when interference was strong. Model parameters were used to compare the relative strengths of intraspecific and interspecific interference in each species. The higher-yielding species, timothy, exerted stronger interference, both within and between species than orchardgrass. Interference was significant early in growth and intensified with increasing population density. The parameters of the yield-density models were also used to assess differential yield responses in the mixtures. Net overyielding occurred in most mixtures because overyielding in timothy was not fully offset by underyielding in orchardgrass. The greatest yield advantage occurred in mixtures containing orchardgrass and timothy in proportions of 2:1. The dynamics of plant growth were followed using methods of plant growth analysis. Absolute growth rate, relative growth rate, unit leaf rate and crop growth rate were among the growth indices showing strong responses to interference. Interference seemed to disturb the time course of growth in a complex way. Allometric relationships between dry weight per plant and either leaf area per plant or tiller number per plant were also affected by interference. The species differed in their allometric responses, and the relationships between allometry and different treatment factors also varied. / Land and Food Systems, Faculty of / Graduate

Thesis (Ph. D.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 117-125). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 13-14). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 174-185). Also available on the World Wide Web.

Inaug.-Diss.--Tübingen. / Lebenslauf. Bibliography: p. 64-68.

Floristic characteristics of the Andover Game Reserve (AGR) were surveyed using an area-based survey technique and classified according to the data recorded from 88 relevés, using the PHYTOTAB-PC software package. Three plant communities, of which two each contain two variants, were described and mapped. The plant communities and their causative environmental factors were validated through detrended- and canonical correspondence multivariate analyses. The plant communities of the AGR were found to typify the floristics associated with the catenal sequences located in undulating areas on granite. Broad-leaved savanna is located at the crest and upper mid-slopes while fine-leaved savanna occurs along the footslopes of the AGR. Seeplines, a characteristic occurrence along catenas, are found at the transitional zone between the upper broad- and lower fine-leaved savanna plant communities. This study forms the basis for the compilation of a revised ecological management plan for the Andover Game Reserve.

Thesis (D.Sc.) -- University of Adelaide, Department of Botany, 1975.