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Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 295-304).

Thesis (M.S.)--West Virginia University, 2005 / Title from document title page. Document formatted into pages; contains vii, 51 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 46-51).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains vii, 73 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (M.A.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 164-173). Also available via Humboldt Digital Scholar.

Field trials were conducted in 2010/11, 2012 and 2013 at the Royal Agricultural University’s Soil Association certified organic Harnhill Manor Farm, Gloucestershire, UK (NGR SP 075 006), to investigate suitable cultivation techniques and legume cover crops for winter and spring wheat production. Cultivation treatments included conventional tillage (CT), low residue non-inversion tillage (LRNiT) and high residue non-inversion tillage (HRNiT) as main plots while undersowing white clover (WC), black medic (BM) or no undersowing (Nus) as subplots. Wheat establishment, growth, grain yield and weeds infestation were assessed to determine the feasibility of these husbandry techniques. For winter wheat in 2010/11, LRNiT seems to be an acceptable alternative for CT. However, for spring wheat in 2012 and 2013, CT seems to be more reliable management option. The performance of undersown legumes was highly weather reliant and inconsistent in the seasons studied. Plant establishment and the succeeding yield parameters were positively related to grain yield. CT had significantly higher plant establishment than LRNiT or HRNiT in each season. For winter wheat, the competition and compensation on shoot density among CT and LRNiT did potentially outweighed cultivation-induced effects on plant establishment. This condition resulted in statistically equivalent crop growth and yields with LRNiT to that of CT. In contrast, for spring wheat in 2012 and 2013, CT that had significantly higher plant establishment also resulted in better crop growth and greater grain yields than other cultivation treatments. In all seasons, HRNiT had significantly lower plant establishment and also reduced grain yields, compared with LRNiT or CT. More soil cultivation also significantly reduced total weeds than less tilled soil such as HRNiT. On the basis of weed species, significantly higher broadleaf weeds were present under CT and significantly higher grass weeds were present under HRNiT. Out of three investigated years, legume cover crops effects were clearly observed only in 2012 with spring wheat. More vigorous growth of WC showed a significantly inverse relationship with broadleaf weeds and total weeds, compared with slow growing BM. This situation, resulted in non-significant yield components or grain yield reduction, compared with non-undersown spring wheat. In this context, white clover seems to be more suitable legume cover crop than black medic.

Thesis--Auburn University, 2008. / Abstract. Includes bibliographic references (p.57-67).

Thesis (M.A.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 69-73). Also available via Humboldt Digital Scholar.

Certified organic farming is developing rapidly world-wide and has become of interest to many farmers, politicians, environmentalists and governments and is practised now in nearly all countries of the world. However, adoption of certified organic farming is not an easy option for farmers and it carries with it several barriers such as technical, economic, social, cultural or legal. The Jordanian Government is interested in proposing organic farming to farmers, but without initially investigating whether or not organic farming will be a suitable system for farmers. Therefore, this research is based on the need to investigate the main barriers and to evaluate opportunities and potential for organic farming in Jordan’s arid lands and to propose an adoption model based on local farmer participation, using farmers’ local knowledge and their initiative, as well as institutional participation. To do so, a two-stage research methodology was employed in this research to gain the necessary data during two periods of fieldwork, April to September 2004 and July to September 2005. During this fieldwork, interviews with 46 farmers using an open questionnaire and interviews with discussion groups and government officials were conducted to investigate barriers and potential for organic farming in Jordan. Also, a national workshop was conducted attended by the Minister of Agriculture and stakeholders to evaluate and to ensure the sustainability of the proposed model. Respondents reported that the main barriers to adopting organic farming included perception, technical, nutrient availability, cultural/social, marketing, economic, institutional, lack of national regulation and lack of information and advice, but that labour was not a barrier. Findings also showed that despite barriers the area has potential for organic production owing to its extensive area, good water quality, potential farmers and international agreements. Based on the results obtained from this research, a suitable organic farming model for Jordan, and other countries having similar conditions, was developed. The model is divided into four levels: government, field, academic and regional and international, and the role of each level and its relationship with other levels is explained. The research shows that the success of this model with delivery of its objectives does not rely on the work of only the Ministry of Agriculture (MoA) or any other single body, but on everyone involved in the provision of organic farming in Jordan. Moreover, the model suggests a potential framework for an action plan on the subject of Jordan and organic farming. Also the methodology developed in this research is considered to be a great help for future researchers wanting to conduct research on organic farming or research related to sustainable agricultural development in the developing world context.