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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Brackish Water as a Factor in Development of the Safford Valley, Arizona, U.S.A.

Resnick, Sol D., DeCook, K. J. 01 1900 (has links)
For presentation at the International Symposium on Brackish Water as a Factor in Development, by the Desert Research Institute at Sede-Boqer at the Ben-Gurion University of the Negev, Beer-Sheva, Israel, January 5-10, 1975. / Introduction: The Safford Valley area lies along the Gila River in the southeastern part of the State of Arizona. The portion of the valley being considered, see Figure 1, is an intermontane trough averaging about 15 miles (24.2 kilometers) in width and about 30 miles (48.3 kilometers) in length. The cultivated lands lie along the Gila River and are 0.5 to 3.5 miles (0.8 to 5.6 kilometers) from the river. The approximately 14,000 inhabitants of the valley are primarily located in the municipalities, and Safford, the largest of the towns, was founded in 1875. Agriculture and agriculture-dependent activities, however, provide the mainstay of the Safford Valley economy accounting for approximately 63 percent of the export employment (State of Arizona, 1971). Like many valleys in arid regions, the Safford Valley, because of an inadequate supply of good quality water, has been forced to depend on ground water of notoriously poor quality. The purpose of this paper is to show how the limitation of available good quality water and the need to use brackish water affects agricultural practices and industrial development in the Safford Valley.
82

The ecology of the world's smallest tortoise, Homopus signatus signatus: effects of rainfall.

Loehr, Victor J. T. January 2008 (has links)
<p>Tortoises appear to be successful in arid ecosystems, where they depend on primary production for their predominantly herbivorous diets. The low primary production of arid regions is exacerbated by priodic droughts, so that iteroparous species such as chelonians require mechanisms to overcome resource shortages. The smallest of all tortoises, Homopus signatus signatus, occurs in a dry winter rainfall area in northwestern South Africa that is threatened with aridification due to regional climate change. The overall aim of this study is to understand the ecology of H. s. signatus, particularly in reference to the importance of rainfall.</p>
83

Resource dynamics and positive and negative interactions between plants in arid systems / Jane Prider.

Prider, Jane (Jane Noeleen) January 2002 (has links)
"June 2002" / Bibliography: leaves 172-198. / viii, 198 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Proposes that the overall outcome of plant interactions along a temporal gradient of resource availability changes from positive during interpulses to negative during pulses. Examines negative interactions between 4 co-dominant chenopod scrubs in arid Acacia papyrocarpa woodlands. Negative interactions were more intense when conditions were least productive. Positive interactions between seedlings also changed over time, depending on the facilitation mechanism. Plant interactions seem to be most intense at the beginning of interpulses when plants are competing for diminishing water, or survivorship is enhanced in the favorable microsites provided by other plants. Later in the interpulse, interactions become less intense as conditions become more stressful and therefore survivorship and growth are affected more by abiotic conditions than plant interactions. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 2002
84

The effect of fertiliser management practices on soil organic matter production in the semi-arid areas : a field and modelling approach / by Kidane Georgis.

Georgis, Kidane January 1997 (has links)
Bibliography: leaves 155-169. / xiv, 169 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the effect of nitrogen fertilizer on dry matter production under differing watering regimes. Investigates the accuracy of different crop and soil organic matter models for predicting crop yield, nitrogen uptake and changes in soil organic carbon and nitrogen. Compares the models with data from long-term field experiments on wheat in Australia and sorghum in Ethiopia. Finds that a higher crop yield and better nitrogen and water utilisation can be achieved if addition of nitrogen fertilizer is balanced with soil water. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy & Farming Systems, 1997?
85

Temporal and spatial relationships of canopy spectral measurements

Bamatraf, Abdurhman Mohamed. January 1986 (has links) (PDF)
Thesis (Ph. D. - Soil and Water Science)--University of Arizona, 1986. / Includes bibliographical references (leaves 170-184).
86

Dynamics of canopy structure and soil surface cover in a semiarid grassland

Goff, Bruce Franklin. January 1985 (has links) (PDF)
Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1985. / Includes bibliographical references (leaves 64-69).
87

A decision methodology for the resource utilization of rangeland watersheds

Khalili, Davar, January 1986 (has links) (PDF)
Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 1986. / Includes bibliographical references (leaves 165-174).
88

The ecology and utilization of dryland lucerne pastures on deep sands in the upper South East of South Australia /

Smith, Murray V. January 1972 (has links) (PDF)
Thesis (M. Ag. Sc.)--University of Adelaide, 1972. / Includes bibliographical references (p. 219-237).
89

Are arid climates more likely to produce monotheistic religions : an archaeological and anthropological perspective /

Dreisbach, Heather. January 2007 (has links)
Thesis (B.S.)--University of Wisconsin -- La Crosse, 2007. / Also available online. Includes bibliographical references.
90

Mycorrhizae, water, and a changing climate how do trees survive in a seasonally dry tropical forest? /

Hasselquist, Niles Jacob, January 2009 (has links)
Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Includes bibliographical references (leaves ). Issued in print and online. Available via ProQuest Digital Dissertations.

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