The promoter system of agriculture extension has been widely studied and accepted as a tool for agriculture development where local resources are scarce. Much development work has been done in Panama using the promoter model. In order to ascertain the local success of this model, promoters trained by World Vision were visited. The adoption of sustainable agriculture practices were measured in five communities where 7 promoters were trained and placed in Veraguas, Panama. Despite the long-term presence of World Vision and trained promoters, only six farmers have adopted at least one sustainable agriculture technique as a result of these extension efforts. Low adoption rates do not necessarily indicate project failure, but does indicate several barriers. These barriers are explored as well as reasons farmers gave for land use. Reasons for S/A use are also explored. Finally, recommendations for improving extension methods and future research are made.

GlobalGAP (previously EurepGAP) is a voluntary business-to-business standard for food audit that has recently achieved the greatest acceptance worldwide (Campbell, Lawrence & Smith 2006) boasting implementation numbers of over 80,000 farms in 80 countries. Compliance with the standard is verified by means of the third party certification (TPC) audit, and is designed to (GlobalGAP 2008) assure European retailers that exporting producers have met their criteria for safe and sustainable agriculture (GlobalGAP 2007b). In 2004, cherry growers in the Southern Interior of British Columbia became the first GlobalGAP certified producers in Canada. This novelty afforded a unique opportunity to observe the introduction of the standard in an industrialized country with well-established regulations and where the capacity of producers to undertake the process was relatively high. A qualitative methodology was used in case studies of two communities to inductively study the implementation of ‘safe and sustainable agriculture’ certification and generate relevant research questions for deeper examination. Sensitizing concepts emerging from observations of the TPC audits (n = 20) evolved into two primary research objectives; 1) to understand the practical application and diffusion of a TPC standard and 2) to explore the efficacy of the TPC standard as a mechanism to promote sustainable agriculture within certain pre-existing contexts. Forty-four follow up interviews were conducted with growers that chose to certify (n = 24), those that did not (n = 14), and other key actors (n = 3). This thesis examines the research objectives over three chapters. The introduction provides the local and global context along with a review of GlobalGAP, agri-food governance and the role of private certification and retailer power. Chapter two presents the technological and sociological factors that influenced the stages of the diffusion of GlobalGAP TPC and compares these factors and outcomes to the technological and sociological components of sustainable agriculture. In the conclusion, policy strategies are offered to maximize the potential for this tool to promote sustainable agriculture along with suggestions for future research on the topic.

In recent years, growing interest towards foods produced from alternative agricultural practices have been seen among consumers. This thesis is an investigation of consumer understanding and attitudes towards information regarding sustainable, organic and local foods and agricultural practices and how such information could affect consumer food product expectation and sensory acceptability. Using internet questionnaires constructed based on common definitions and popular beliefs, 172 primary grocery shoppers were surveyed regarding their perception concerning information related to these alternative agricultural practices and foods. Results obtained from statistical analyses revealed the existence of various dimensions concerning the understanding and attitudes towards these concepts. Segmentations based on their understanding and attitudes towards these concepts were also found within the sampled population. Furthermore, by utilizing the theory of assimilation and contrast, a three-part sensory study was conducted, with 49 consumers from the Niagara Peninsula, to examine the impact of information regarding production methods (organic vs. conventional) and product origins (local vs. imported) on consumer expectation and acceptability of yellow peaches. Despite of some peach samples being under-ripe, a significant positive labeling effect has been observed in hedonic rating and perceived intensity of sensory characteristics when the joint organic and local label was presented. A similar labeling effect, however, was not observed in monetary valuation of willingness to pay. / New Directions Research Program / Ontario Ministry of Agriculture, Food, and Rural Affairs

Arbuscular mycorrhizal fungi (AMF) represent an ancient and critical symbiotic partner with the majority of land plants, understood to promote ecosystem productivity and biodiversity and are also important to ecologically sound land management practices. The fungus is thought to be over 400 million years old, and due to a lack of an observable sexual cycle, has been placed into a select group of eukaryotes called 'ancient asexuals', which seemingly defy evolutionary theory by persisting for an extended period of time in the absence of sexual reproduction. Recently however, molecular evidence has accumulated which may suggest AMF harbour a cryptic sexual cycle. In the first chapter of this thesis, entitled "Searching for clues of sexual reproduction in the genomes of arbuscular mycorrhizal fungi", I review evidence supporting this notion of a cryptic sexual cycle in AMF which includes: the presence of recombinational events, meiosis-specific genes as well as mating-specific transcription factors called SexM and SexP of the MATA_HMG protein family which are otherwise found only in the genomes of sexual fungi. In the second chapter, I present the main research of my MSc work where I used bioinformatic, population genetic, molecular and experimental approaches to build on this existing evidence of sexuality in AMF. These findings include the presence of a dramatically expanded family of MAT-HMG genes which are present in several isolates of the Rhizophagus irregularis and also harbour significant allele variation amongst these isolates, some of which resembles variation expected at MAT-genes in other fungi. Q-RT-PCR procedures revealed that at least some of these genes tend to increase in expression during crosses of R. irregularis isolates. We also uncovered the presence of a unique genomic region where at least three of these genes are located in tandem. Finally, several tests of recombination support the presence of intraisolate as well as interisolate recombination events occurring between these MAT-HMG genes.

The effect of management practices used by smallholder farmers to improve soil quality and increase maize yield was examined in an 80 ha. micro-watershed of central Malawi. Because of the complexity inherent in smallholder farming systems, this research proposed the combination of participatory methods with analytical techniques developed in field ecology, such as multivariate and spatial analysis. During a Participatory Rural Appraisal (PRA), farmers identified factors potentially influencing soil quality and maize yield. One hundred and seventy-six (176) plots were located in twenty-nine (29) fields and characterized for management practices and biophysical characteristics. Soil samples were collected at each plot and analysed for a suite of properties. The maize yield was measured for both 1996--97 and 1997--98 seasons. A formal survey was used to gather information on household characteristics. Results showed that management practices that were promoted by a previous extension project, such as alley cropping and the planting of grass on contour ridges, were strongly correlated and found mainly in fields located closer to house compounds. Farmers with a higher proportion of their land under wetland gardens tended to use less agroforestry. Food security was associated with households that were able to purchase inorganic fertilizers, had larger landholding size, and owned livestock and woodlots. The effect of management practices on maize yield and soil quality was partially confounded with characteristics of the plot, such as slope, degradation level, number of years under cultivation or pest damage. Higher maize yield was observed in plots that were better managed, as expressed by the combination of different management practices, lower pest incidence, fewer erosion signs and higher soil fertility. Some positive effects of alley cropping on soil quality were observed in plots that were cultivated for a longer period and located on flatter land. This study demo

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.

Doctor of Philosophy / Precision Agriculture (PA) strives towards holistic production and environmental management. A fundamental research challenge is the continuous expansion of ideas about how PA can contribute to sustainable agriculture. Some associated pragmatic research challenges include quantification of spatio-temporal variation of crop yield; crop growth simulation modelling within a PA context and; evaluating long-term financial and environmental outcomes from site-specific crop management (SSCM). In Chapter 1 literature about managing whole farms with a mind towards sustainability was reviewed. Alternative agricultural systems and concepts including systems thinking, agro-ecology, mosaic farming and PA were investigated. With respect to environmental outcomes it was found that PA research is relatively immature. There is scope to thoroughly evaluate PA from a long-term, whole-farm environmental and financial perspective. Comparatively, the emphasis of PA research on managing spatial variability offers promising and innovative ways forward, particularly in terms of designing new farming systems. It was found that using crop growth simulation modelling in a PA context is potentially very useful. Modelling high-resolution spatial and temporal variability with current simulation models poses a number of immediate research issues. This research focused on three whole farms located in Australia that grow predominantly grains without irrigation. These study sites represent three important grain growing regions within Australia. These are northern NSW, north-east Victoria and South Australia. Note-worthy environmental and climatic differences between these regions such as rainfall timing, soil type and topographic features were outlined in Chapter 2. When considering adoption of SSCM, it is essential to understand the impact of temporal variation on the potential value of managing spatial variation. Quantifying spatiotemporal variation of crop yield serves this purpose; however, this is a conceptually and practically challenging undertaking. A small number of previous studies have found that the magnitude of temporal variation far exceeds that of spatial variation. Chapter 3 of this thesis dealt with existing and new approaches quantifying the relationship between spatial and temporal variability in crop yield. It was found that using pseudo cross variography to obtain spatial and temporal variation ‘equivalents’ is a promising approach to quantitatively comparing spatial and temporal variation. The results from this research indicate that more data in the temporal dimension is required to enable thorough analysis using this approach. This is particularly relevant when questioning the suitability of SSCM. Crop growth simulation modelling offers PA a number of benefits such as the ability to simulate a considerable volume of data in the temporal dimension. A dominant challenge recognised within the PA/modelling literature is the mismatch between the spatial resolution of point-based model output (and therefore input) and the spatial resolution of information demanded by PA. This culminates into questions about the conceptual model underpinning the simulation model and the practicality of using point-based models to simulate spatial variability. iii The ability of point-based models to simulate appropriate spatial and temporal variability of crop yield and the importance of soil available water capacity (AWC) for these simulations were investigated in Chapter 4. The results indicated that simulated spatial variation is low compared to some previously reported spatial variability of real yield data for some climate years. It was found that the structure of spatial yield variation was directly related to the structure of the AWC and interactions between AWC and climate. It is apparent that varying AWC spatially is a reasonable starting point for modelling spatial variation of crop yield. A trade-off between capturing adequate spatio-temporal variation of crop yield and the inclusion of realistically obtainable model inputs is identified. A number of practical solutions to model parameterisation for PA purposes are identified in the literature. A popular approach is to minimise the number of simulations required. Another approach that enables modelling at every desired point across a study area involves taking advantage of high-resolution yield information from a number of years to estimate site-specific soil properties with the inverse use of a crop growth simulation model. Inverse meta-modelling was undertaken in Chapter 5 to estimate AWC on 10- metre grids across each of the study farms. This proved to be an efficient approach to obtaining high-resolution AWC information at the spatial extent of whole farms. The AWC estimates proved useful for yield prediction using simple linear regression as opposed to application within a complex crop growth simulation model. The ability of point-based models to simulate spatial variation was re-visited in Chapter 6 with respect to the exclusion of lateral water movement. The addition of a topographic component into the simple point-based yield prediction models substantially improved yield predictions. The value of these additions was interpreted using coefficients of determination and comparing variograms for each of the yield prediction components. A result consistent with the preceding chapter is the importance of further validating the yield prediction models with further yield data when it becomes available. Finally, some whole-farm management scenarios using SSCM were synthesised in Chapter 7. A framework that enables evaluation of the long-term (50 years) farm outcomes soil carbon sequestration, nitrogen leaching and crop yield was established. The suitability of SSCM across whole-farms over the long term was investigated and it was found that the suitability of SSCM is confined to certain fields. This analysis also enabled identification of parts of the farms that are the least financially and environmentally viable. SSCM in conjunction with other PA management strategies is identified as a promising approach to long-term and whole-farm integrated management.

Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1994? / Includes bibliographical references (leaves 74-84).

Thesis (M.Sc.)(Hons.) -- University of Western Sydney, [2002]. / "A thesis presented to the School of Environment and Agriculture, University of Western Sydney in fulfilment of the requirements for the degree of Master of Science (Honours) " Bibliography: leaves 133-140.

Thesis (MSc. (Honours)) -- University of Western Sydney, Hawkesbury, 1998. / "A thesis submitted in fulfilment of the requirements for a degree of Master of Science (Honours), Faculty of Environmental Management and Agriculture, University of Western Sydney - Hawkesbury." "January 1998" Bibliography: leaves 207 - 227.