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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.
61

Effectiveness of an agricultural technology research and development project for increasing sustainability of cropping systems in upland areas of Yunnan Province, China

Subedi, Madhu January 2006 (has links)
Continued increase in population and escalating environmental degradation have changed the priorities of agricultural development projects in developing and emerging countries towards both increasing production or productivity and improving sustainability. The long-term success of these development projects, especially in terms of improving sustainability, depends on how widely those improved practices which are shown to be effective in achieving the technical objectives, are adopted/adapted by farmers in the targeted region. In these terms, many projects in recent years may be considered to be relatively unsuccessful. This study aimed to investigate the factors contributing to the effectiveness of agricultural technology research and development projects in improving the sustainability of cropping systems in upland areas of China, together with the factors that might limit their effectiveness. This has involved both a review of recent projects carried out in the region and detailed monitoring and evaluation of one such project carried out in South West China – the SHASEA project. The SHASEA Project was implemented in Wang Jia catchment in Yunnan Province using holistic and multi-disciplinary approaches to address the twin objectives of increasing productivity of maize, wheat and soybean in a more sustainable and environmentally-friendly way. It introduced into the catchment a range of novel or modified cropping practices, which had been evaluated in plot studies over the preceding six years, together with biological and engineering measures designed to stabilise large scale soil movements in lateral gullies and the main stream. The SHASEA Project was successful in achieving its short-term scientific and technical objectives, but was too short to determine the level of adoption by farmers in the locality. The present study has used a range of approaches to evaluate the effectiveness of this Project, to monitor the biological, environmental and socio-economic impacts and investigate the perceptions of the farmers about the Project and the likelihood of their adoption of the recommended practices. Participatory approaches were used wherever possible, including detailed household surveys, PRA workshops and discussions with Key Informants. Field surveys and direct observations were also made, together with a limited economic analysis of the modified cropping practices introduced into the catchment. It was found that the farmers had different perceptions about the range of practices introduced into the catchment. Some were clearly preferred, such as contour cultivation and were likely to be adopted, while others were seen as inappropriate, such as straw mulching and intercropping, and were unlikely to be adopted. The benefits of an innovative, integrated cropping system, INCOPLAST, were not fully appreciated by the farmers. Other practices would only be adopted if the financial returns were favourable, such as the use of polythene mulch. Longer-term measures, such as tree planting schemes, were regarded favourably, but adoption would still depend on economic returns and related issues such as land security. An irrigation scheme was suggested by the farmers, but after installation it was not used extensively for the staple crops in the catchment. It was found that farmers planned to use the irrigation for higher value crops such as tobacco, after the end of the Project. It has been concluded that, despite the technical and scientific success of the Project, long-term adoption of many of the practices introduced into the catchment will be low, unless considerable incentives are used or much more effective dissemination techniques employed. It is considered that the outcomes would have improved considerably if participatory approaches had been used from the outset, to engage farmers more fully with the project, to ensure that the practices introduced were as appropriate as possible, to achieve greater ownership of the objectives and outcomes, leading to higher adoption rates. More emphasis should have been given to the dissemination of the outcomes at farmer level outside the catchment of study and there should have been more involvement with the regional policy makers and extension officials throughout the programme. Longer-term improvements in sustainability at the catchment level have not yet been demonstrated. These outcomes are discussed within the context of other agricultural projects carried out in South East Asia and other developing regions. Based on the outcomes and conclusions from this study, a series of recommendations are made which are presented as good practices for future agricultural development projects in South East Asia.
62

Soil water and nitrogen dynamics of farming systems on the upper Eyre Peninsula, South Australia

Adcock, Damien Paul January 2005 (has links)
In the semi - arid Mediterranean - type environments of southern Australia, soil and water resources largely determine crop productivity and ultimately the sustainability of farming systems within the region. The development of sustainable farming systems is a constantly evolving process, of which cropping sequences ( rotations ) are an essential component. This thesis focused on two important soil resources, soil water and nitrogen, and studied the effects of different crop sequences on the dynamic of these resources within current farming systems practiced on the upper Eyre Peninsula of South Australia. The hypothesis tested was that : continuous cropping may alter N dynamics but will not necessarily alter water use efficiency in semi - arid Mediterranean - type environments. Continuous cropping altered N - dynamics ; increases in inorganic N were dependent on the inclusion of a legume in the cropping sequence. Associated with the increase in inorganic N supply was a decrease in WUE by the subsequent wheat crop. Overall, estimates of water use efficiency, a common index of the sustainability of farming systems, in this study concur with reported values for the semi - arid Murray - Mallee region of southern Australia and other semi - arid environments worldwide. Soil water balance and determination of WUE for a series of crop sequences in this thesis suggests that the adoption of continuous cropping may increase WUE and confer a yield benefit compared to crop sequences including a legume component in this environment. No differences in total water use ( ET ) at anthesis or maturity were measured for wheat regardless of the previous crop. Soil evaporation ( E [subscript s] ) was significantly affected by crop canopy development, measured as LAI from tillering until anthesis in 2002, however total seasonal E [subscript s] did not differ between crop sequences. Indeed in environments with infrequent rainfall, such as the upper Eyre Peninsula, soil evaporation may be water - limited rather than energy limited and the potential benefits from greater LAI and reduced E [subscript s] are less. Greater shoot dry matter production and LAI due to an enhanced inorganic N supply for wheat after legumes, and to a lesser degree wheat after canola, relative to continuous cereal crop sequences resulted in increases in WUE calculated at anthesis, as reported by others. Nonetheless the increase in WUE was not sustained due to limitations on available soil water capacity caused by soil physical and chemical constraints. Access to more soil water at depth ( > 0.8m ) through additional root growth was unavailable due to soil chemical limitations. More importantly, the amount of plant available water within the ' effective rooting depth ' ( 0 - 0.8m ) was significantly reduced when soil physical factors were accounted for using the integral water capacity ( IWC ) concept. The difference between the magnitude of the plant available water capacity and the integral water capacity was approximately 90mm within the ' effective rooting depth ' when measured at field capacity, suggesting that the ability of the soil to store water and buffer against periodic water deficit was severely limited. The IWC concept offers a method of evaluating the physical quality of soils and the limitations that these physical properties, viz. aeration, soil strength and hydraulic conductivity, impose on the water supply capacity of the soil. The inability of the soil to maintain a constant supply of water to satisfy maximal transpiration efficiency combined with large amounts of N resulted in ' haying off ', and reduced grain yields. A strong negative linear relationship was established between WUE of grain production by wheat and increasing soil NO [subscript 3] - N at sowing in 2000 and 2002, which conflicts with results from experiments in semi - arid Mediterranean climates in other regions of the world where applications of N increased water use efficiency of grain. Estimates of proportional dependence on N [subscript 2] fixation ( % N [subscript dfa] ) for annual medics and vetch from this study ( 43 - 80 % ) are comparable to others for environments in southern Australia ( < 450mm average annual rainfall ). Such estimates of fixation are considered low ( < 65 % ) to adequate ( 65 - 80 % ). Nevertheless, the amount of plant available N present at sowing for subsequent wheat crops, and the occurrence of ' haying off ', suggests that WUE is not N - limited per se, as implied by some reports, but constrained by the capacity of a soil to balance the co - limiting factors of water and nitrogen. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2005.
63

Adoption of conservation tillage : an application of duration analysis

D'Emden, Francis Herbert January 2006 (has links)
The global adoption and diffusion of conservation tillage has made considerable progress over the last 20 years. No-till and zero-tillage could be seen as representing the current technological end-point of the conservation tillage movement. This thesis uses descriptive statistics and both logit and duration regressions to analyse the influence of cross-sectional and time-dependent factors on the probability of no-till adoption by growers in Australia’s southern grain growing regions. Cross-section and time-series data on individual adoption decisions was gathered through interviews and employed in conjunction with generic time series data from various government agencies in a duration analysis modelling framework. Descriptive statistics suggest that weed management and herbicide resistance are important considerations for growers in their tillage decisions, predominantly due to the substitution of herbicides for the physical weed control provided by cultivation. Logit and duration regressions identify a number of significant factors influencing growers’ adoption decisions. These include growers’ perceptions of herbicide efficacy and sowing timeliness in no-till systems; the declining price of glyphosate relative to diesel; average annual rainfall and growers’ proximity to other adopters and opportunities to observe the beneficial effects of no-till. The results suggest that research and development of integrated weed management practices that are compatible with no-till systems is highly important if no-till systems are to be sustained in Australia’s southern wheatbelt. Such research and development should acknowledge the high value which growers place on locally generated information and the channels used to acquire such information, namely local extension events and consulting services. This thesis shows how duration analysis, with its ability to take account of both cross sectional and time-varying factors, can provide a statistical modelling framework better suited to the study of adoption decisions than traditional cross sectional methods based on logit and tobit analyses.
64

Soil nitrogen fluxes in Swedish and Nigerian agricultural systems /

Röing, Kristina, January 2005 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
65

Root associated fungi of conifer seedlings and their role in afforestation of agricultural land /

Menkis, Audrius, January 2005 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.
66

Changes in soil physical properties under raised bed cropping /

Holland, Jonathan Eddison. January 2006 (has links)
Thesis (Ph.D.)--University of Melbourne, School of Resource Management, Faculty of Land and Food Resources, 2006. / Typescript. Includes bibliographical references (leaves 247-274).
67

Quercetin content in yellow onion (Allium cepa L.) : effects of cultivation methods, curing and storage /

Mogren, Lars, January 2006 (has links) (PDF)
Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.
68

Cover crop and soil amendment effects on carbon sequestration in a silage corn-soybean cropping system

Fronning, Bradley Eric. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Crop & Soil Sciences, 2008. / Title from PDF t.p. (viewed on Aug. 17, 2009) Includes bibliographical references. Also issued in print.
69

The foraging pig : resource utilisation, interaction, performance and behaviour of pigs in cropping systems /

Andresen, Niels. January 2000 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2000. / Thesis based on experience collected between 1994-2000 working with outdoor pigs and 4 papers, which are included in the volume. Includes bibliographical references.
70

Continuous measurement of soil surface carbon dioxide, nitrous oxide and methane fluxes to estimate global warming potentials in Great Plains maize-based agroecosystems

Shen, Hui. January 2008 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Jan. 15, 2009). PDF text: 147 p. : col. ill. ; 9 Mb. UMI publication number: AAT 3316416. Includes bibliographical references. Also available in microfilm and microfiche formats.

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