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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.

Thesis (doctoral)--Justus-Liebig-Universität Giessen, 2000. / Includes bibliographical references (p. 163-176).

Thesis (doctoral)--Universität, Hohenheim, 2007. / Includes bibliographical references (p. 231-238).

In this paper, I show the experience  obtained in Mexico  and Latin America from the application of the Methodological Framework for the Evaluation of Management Systems with Sustainability lndicators between 1999 and 2005. These are diverse efforts to increase and evaluare the sustainability of agro ecosystems under various conditions, with different constraints and results; in sorne cases, these include the comparison of contrasting systems and, in others, the changes obtained for the same system under alternative ways of management.All the cases are attempts to make operative the concept of sustainability applied to sustainable development, specifically supported over the experience of evaluating agro ecosystems under the conditions of the Latin American countries. / En este trabajo  se presenta  la experiencia  obtenida  en México  y Latinoamérica a partir de la aplicación, entre 1999 y 2005, del Marco Metodológico para la Evaluación de Sistemas de Manejo Incorporando Indicadores de Sustentabilidad. Estos constituyen esfuerzos diversos para incrementar y evaluar la sustentabilidad de sistemas agropecuarios bajo condiciones variadas, con limitaciones y resultados diferentes, e incluyen, en algunos casos, la comparación de sistemas contrastantes y, en otros, los cambios logrados en el mismo sistema bajo formas de manejo alternativas.Todos los casos presentados  suponen  intentos  de hacer operativo el concepto de sustentabilidad en la búsqueda de desarrollo, y se basan específicamente en la experiencia  de evaluación  de sistemas  agropecuarios  en las condiciones  de países latinoamericanos.

Information and communication technologies (ICTs) have been widely researched as a mechanism for improving the socio-economic status of disadvantaged, rural communities. In order to do this numerous technology-based initiatives have been introduced into disadvantaged, rural communities to assist them in various aspects of their lives. Unfortunately, even when the proposed benefit of a particular technology is clearly evident to its initiators, the adoption by the target users is often uncertain. This has also been the case with e-commerce in agriculture. Despite the numerous benefits of e-commerce for agricultural producers, the uptake has been low. Trust is a critical pre-condition for the adoption of e-marketplaces. E-marketplaces expose consumers to the risk of non-delivery or misrepresentation of goods ordered and the misuse of personal information by external parties. Additionally, the time investment needed to make a shift to e-marketplaces and the opinions of important reference groups affects the user’s willingness to trust and depend on an e-marketplace. This study was undertaken to assess the extent to which rural users with limited ICT experience would trust and, consequently, adopt an e-marketplace to support agricultural trade. A pragmatic philosophy was adopted in this study, indicating that the researcher’s view of reality is founded on the practical implications and outcomes that are observed. This study used a Canonical Action Research strategy to design, develop and deploy a voice based e-marketplace to assist the trading activities of a Western Cape based aloe community. The community was allowed to utilise thee-marketplace over a period of eight weeks. Thereafter, interviews were held with the participants to investigate their perceptions of the technology. As a result, a model proposing the factors that must be in place for trust to be achieved in a voice based e-marketplace was proposed. The study found that the trustworthiness of a technology results from the technology’s technical capability to satisfy the needs of its users reliably. Usability and security were found to be important determinants of the trustworthiness of a technology. Furthermore, the requirements elicitation process was found to be central to achieving trust as it defines the necessary criteria for developing secure, usable, functional, and reliable technologies that meet the needs of their users.

Este trabalho traz como eixo central o entendimento das diferentes formas de intervenção do Estado por meio de políticas públicas de reordenamento agrário e sua influência no processo de obtenção e utilização da renda agrícola. Desta forma, entendendo até quando as políticas públicas, especificamente aquelas destinadas ao reordenamento agrário, devem observar a ordem local, visto que esta ordem é construída de maneira a atender as necessidades destas sociedades, trazendo como hipótese de encaminhamento e solução a diferenciação das políticas atendendo as peculiaridades sociais. Tem como objetivo geral compreender como as diferentes políticas públicas destinadas ao desenvolvimento rural, especificamente as políticas de reordenamento agrário tem influenciado o processo de geração de renda (agrícola e de autoconsumo) em contextos culturais e de organização produtiva diversificada em três comunidades rurais do município de Presidente Juscelino/MA, sendo elas: Boa Vista dos Pinhos, Juçaral dos Pretos e Folhal. A metodologia utilizada para a realização deste trabalho foi inicialmente o levantamento histórico dos sistemas agrários, visando a compreensão da estrutura agrária e social em questão, posteriormente em outro momento do trabalho foram aplicados questionários semiestruturados com o objetivo de obter dados quanti qualitativos sobre o processo de geração da renda monetária, auto consumo, sendo encontrado nesse momento uma nova forma de ganhos conseguidos por meio da organização e da manutenção da estrutura social. Levando-se em conta referenciais antropológicos efetuou-se uma leitura do processo por meio da produção de farinha como eixo norteador e gerador das condições necessárias para produzir desenvolvimento. / This work has as central axis to understanding the different forms of State intervention, through public policies of agrarian reordering and its influence in the process of obtaining and using agricultural income. In this way, understanding even when public policies, specifically those aimed at agrarian reordering, must obey the local order. Since this order is constructed in such way as to meet the needs of these societies, bringing as a hypothesis of routing and solution the differentiation of the Policies taking into account social peculiarities. With the general objective of understanding how the different public policies aimed at rural development, specifically agrarian reordering policies, have influenced the process of income generation (agricultural and self-consumption) in cultural contexts and of diverse productive organization in three rural communities of the municipality of Presidente Juscelino/MA, being Boa Vista dos Pinhos, Juçaral dos Pretos and Folhal. The methodology used to carry out this work was initially the historical survey of the agrarian systems, with a view to understanding the agrarian and social structure in question, Later in another moment of the work, semistructured questionnaires were applied with the objective to obtaining qualitative and quantitative data on the process of generating monetary income. Self consumption, being found in this moment a new form of gains obtained through the organization and maintenance of the formal structure. Taking into account anthropological references was made reading of the process through the production of flour as a guiding axis and generator of the necessary conditions to generate development.

Este trabalho traz como eixo central o entendimento das diferentes formas de intervenção do Estado por meio de políticas públicas de reordenamento agrário e sua influência no processo de obtenção e utilização da renda agrícola. Desta forma, entendendo até quando as políticas públicas, especificamente aquelas destinadas ao reordenamento agrário, devem observar a ordem local, visto que esta ordem é construída de maneira a atender as necessidades destas sociedades, trazendo como hipótese de encaminhamento e solução a diferenciação das políticas atendendo as peculiaridades sociais. Tem como objetivo geral compreender como as diferentes políticas públicas destinadas ao desenvolvimento rural, especificamente as políticas de reordenamento agrário tem influenciado o processo de geração de renda (agrícola e de autoconsumo) em contextos culturais e de organização produtiva diversificada em três comunidades rurais do município de Presidente Juscelino/MA, sendo elas: Boa Vista dos Pinhos, Juçaral dos Pretos e Folhal. A metodologia utilizada para a realização deste trabalho foi inicialmente o levantamento histórico dos sistemas agrários, visando a compreensão da estrutura agrária e social em questão, posteriormente em outro momento do trabalho foram aplicados questionários semiestruturados com o objetivo de obter dados quanti qualitativos sobre o processo de geração da renda monetária, auto consumo, sendo encontrado nesse momento uma nova forma de ganhos conseguidos por meio da organização e da manutenção da estrutura social. Levando-se em conta referenciais antropológicos efetuou-se uma leitura do processo por meio da produção de farinha como eixo norteador e gerador das condições necessárias para produzir desenvolvimento. / This work has as central axis to understanding the different forms of State intervention, through public policies of agrarian reordering and its influence in the process of obtaining and using agricultural income. In this way, understanding even when public policies, specifically those aimed at agrarian reordering, must obey the local order. Since this order is constructed in such way as to meet the needs of these societies, bringing as a hypothesis of routing and solution the differentiation of the Policies taking into account social peculiarities. With the general objective of understanding how the different public policies aimed at rural development, specifically agrarian reordering policies, have influenced the process of income generation (agricultural and self-consumption) in cultural contexts and of diverse productive organization in three rural communities of the municipality of Presidente Juscelino/MA, being Boa Vista dos Pinhos, Juçaral dos Pretos and Folhal. The methodology used to carry out this work was initially the historical survey of the agrarian systems, with a view to understanding the agrarian and social structure in question, Later in another moment of the work, semistructured questionnaires were applied with the objective to obtaining qualitative and quantitative data on the process of generating monetary income. Self consumption, being found in this moment a new form of gains obtained through the organization and maintenance of the formal structure. Taking into account anthropological references was made reading of the process through the production of flour as a guiding axis and generator of the necessary conditions to generate development.

Chosen agriculture farm: Dubné corporation is in South Bohemia region. Analysis of inner structure of agricultural system was calculated for ten-year period 1997 {--} 2006. Data used for analysis: acreage and yield of individual crops, consumption of mineral fertilizers, cattle stock. On the basis of this analysis, using carbon balance principle, variants of agricultural inner structure project have been worked out, aimed at bioenergy production: cereals for production of bioethanol, raps for production of oil, biogas.