The water acquisition strategies of trees in agroforestry systems may affect adjacent crops through competition for resources. This study characterizes the water uptake zones of Juglans nigra (walnut) and Populus sp. (hybrid of Populus deltoids X Populus nigra clone DN-177) (poplar) in a temperate agroforestry system. Isotopic analysis (δ18O) of soil water and tree xylem water occurred in early season and late season samples from the Agroforestry Research Station in Guelph, Ontario, Canada. Direct inference and multiple source mass-balance approaches showed that poplar exhibited a primary soil water uptake zone at 20 cm in early season, while walnut uptake was higher in the soil profile at 10 cm. Late season water uptake zones shifted to lower in the soil profile (40-70 cm) for both poplar and walnut trees. This study indicates: i) species dependent water acquisition zones, and ii) a shift to lower in the soil profile later in the growing season.

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Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 8, 2007) Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Swedish University of Agricultural Sciences, 2001. / Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains viii, 72 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 62-65).

Agroforestry offers a land-use management methodology that may provide solutions to environmental degradation in the tropics. However, practitioners of agroforestry are faced with the dilemma of clearing more forest cover in order to increase crop size and sustain their income. The aim of this study is to understand the agroforester’s dilemma and to measure the value of the agroforestry ecosystem stewardship in yerba maté (Ilex paraguariensis A. St. Hil.) agroforestry parcels of the South American Atlantic forest eco-region. Biodiversity, carbon sequestration and vegetation cover were measured to be considerably higher in yerba maté (Ilex paraguariensis A. St. Hil.) agroforestry plantations than in neighboring monoculture crops. Agroforestry vegetation cover values were measured to have between 65-89% cover while monocultures had roughly 25% cover. Agroforestry stored carbon values ranged between 154.7-172.7 Mg C ha-1, compared to monoculture plantation values of 81.3 Mg C ha-1. Finally, as measured using the Shannon index, values of species richness ranged from 2.7-3.5 in agroforestry parcels and between 0.9-1.3 in monocultures, and values of evenness ranged between 0.6 and 0.8 in agroforestry parcels, and 0.2 in monocultures. These findings illustrate that yerba maté agroforestry can potentially contribute as a regional climate change mitigation strategy. Valuating and monetizing ecosystem services and engaging smaller farmers with worldwide ecosystem marketplaces offer the potential to expand the dialogue around payments for the valuable ecosystem services that agroforesters are providing. An analysis of market prices available within the ecosystem marketplace for total ecosystem services being conserved on agroforestry parcels amounted to a range in value between $16 – $160 ha-1 yr-1. To address environmental degradation in the Atlantic Forest region, in South America, governments should motivate environmental conservation to support a shift towards sustainable yerba maté production which supports livelihoods of small-scale farmers, economic justice and environmental sustainability. / Graduate

Thesis (MSc.(Pasture Science)--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Mémoire (M.E.S.R.)-Université du Québec à Chicoutimi, 1984. / "Mémoire présenté pour satisfaire partiellement aux exigences du programme de maîtrise en études régionales en vue de l'obtention du diplôme de maîtrise ès arts" CaQCU Bibliographie: viii-xiv. Document électronique également accessible en format PDF. CaQCU