Condensed tannins (CT) play an integral role in terrestrial nutrient cycling. Despite being the fourth most abundant terrestrial biochemical product, the regulatory processes of tannin production in plants and their subsequent ecological influences are not completely understood. The defining characteristic of CT’s is their affinity for proteins, though they willingly interact with minerals, carbohydrates, and other polyphenolic compounds. Previous tannin investigations in agriculture have centred on bioactivity related to ruminant digestive physiology and pathology. These studies have revealed that CT’s have the potential to increase liveweight gain, wool production, and sheep ovulation rates, prevent pasture bloat, reduce enteric and stockpiled manure greenhouse gas (GHG) emissions, and control gastrointestinal parasites. The present study has explored how tannin-containing resident plant material and applied manure derived from tannin-containing beef cattle diets influences tame forage biomass yield, proximate analysis, and tannin production, as well as residual fall soil nutrient status, in southern Manitoba. To test these hypotheses, we conducted an experiment over two growing seasons (2007-2008) where in the fall of 2007, both tannin-derived (sainfoin, Onobrychis viciifolia) and non-tannin (alfalfa, Medicago sativa) composted beef manures were applied at a rate of 44.8 t/ha in a randomized split plot fashion, including a manure-free control, on a four repetition randomized complete block design which included both tannin-containing and non-tannin containing forage monocultures and mixtures. Plant samples were harvested in two cuts, and soil measurements were taken in the fall of both years. It was found that across all sainfoin treatments, manure origin did not have a significant effect on plant CT concentration, which was extremely variable within treatments and cuts. Over four harvest dates, sainfoin CT concentrations ranged from 14.1 g/kg to 91.9 g/kg in monoculture plots, and 16.6 g/kg to 123 g/kg when grown in a mixture with meadow brome. In most cases, the presence of either manure type did not significantly affect soil nutrient status or forage yield, though results were similarly variable. Using a stepwise regression which included all soil and plant measurements across all cuts and treatments, it was found that NDF (R2 = 0.548) and plant phosphorus (R2 = 0.126) were the only significant model contributors to tannin concentration in sainfoin at P < 0.15. These findings suggest that nutrient effects of beef cattle manure are not realized in either plant or soil in the year following application, and consequently, that tannin agronomy requires longer-term analysis.

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 153-180.

Thesis (M. Sc.) Uppsala : Sveriges lantbruksuniv., 2007.

Thesis (D. Sc.)--University of Adelaide, Dept. of Botany, 1996? / Includes bibliographical references.

Thesis (Ph.D.)--Michigan State University. Dept. of Crop and Soil Sciences, 2008. / Title from PDF t.p. (viewed on July 9, 2009) Includes bibliographical references. Also issued in print.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 40-51).

Thesis (M. Agr. Sc.) -- Lincoln University, 2009. / Also available via the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 125-147).

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 148-156). Also available on the Internet.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 56-60).