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Tesi sul tema "Agricultural systems"
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1
Kramar, Laura L. "Assessing the Sustainability of Agricultural Systems". Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/KramarLL2007.pdf.
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2
Window, Marc. "Security in Precision Agriculture : Vulnerabilities and risks of agricultural systems". Thesis, Luleå tekniska universitet, Datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74309.
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3
Malagnino, Remo Alessio <1986>. "Energy Systems Optimization on Agricultural Sector". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7464/.
Testo completoAbstract (sommario):
Come molti altri settori produttivi, anche l'agricoltura deve affrontare una crescente dipendenza energetica da elettricità, petrolio e gas naturale. Tuttavia, l'agricoltura può rispondere direttamente a tali richieste ricorrendo alle fonti di energia rinnovabili (FER), come il solare fotovoltaico (PV) e gli impianti biogas/biometano (BP).
Questi sistemi sono stati fortemente incentivati in passato. Gli attuali sistemi d’incentivazione prevedono invece sussidi commisurati alle caratteristiche aziendali come stalle, fienili, disponibilità di biomasse, ecc. Per questi motivi, per quanto riguarda il settore FV, è necessario utilizzare modelli analitici affidabili per valutare l’orientamento e la tecnologia migliore, in particolare per generatori integrati architettonicamente. Per la produzione di biometano, gli impianti di piccole dimensioni risultano quelli maggiormente incentivati previa alimentazione con sottoprodotti agro-industriali. Tuttavia, le loro performance dipendono fortemente dalla tecnologia d’upgrading.
Pertanto, le prospettive economiche offerte da questi sistemi RES sono legate alla scelta della tecnologia da impiegare e non più esclusivamente al semplice dimensionamento. Su questa base, l'obiettivo principale di questo lavoro è stato lo sviluppo di strumenti di supporto decisionali (DSSS) per l'ottimizzazione energetica d’impianti FV e BP.
Un primo studio si è focalizzato sull’analisi prestazionale per singolo componente e globale d’impianti FV installati in un’azienda agricola. Inoltre, una procedura analitica di ottimizzazione dei parametri d’impianto è stata definita per massimizzare il rendimento elettrico di un generatore integrato architettonicamente rispetto ad un’installazione a terra. Attraverso una serie d’informazioni tecnico-economiche di tecnologie di upgrading, un secondo studio è stato condotto con l'obiettivo di sviluppare un DSS per valutare la marginalità sul reddito aziendale data dall’installazione on-farm di un impianto BP collegato alla rete del gas naturale.
I risultati dei due studi hanno dimostrato come questi DSS possono essere utili strumenti per valutare preventivamente le diverse potenzialità offerte da impianti FV e BP in base alle caratteristiche di un’azienda agricola.Like many other productive sectors, even agriculture must tackle an increasing energy dependency on electricity, petroleum and natural gas. Nevertheless, agriculture can directly respond to such request thanks to renewable energy systems (RES) like solar photovoltaic (PV) and biogas/biomethane (BP) plants. These systems have been strongly incentivized in the past. On the contrary, current incentive schemes provide feed-in-tariffs proportionate to farming characteristics as stables, barns, biomass availability, etc. For this reason, as regards the PV sector, it is required to use reliable analytical models for assessing the best orientation and technology, in particular for architecturally integrated generators. For the biomethane production, small-medium plants have stronger incentives in particular using agro-food by-products as feed. However, their performances are strongly dependent on biomethane upgrading technology. Thus, the economic prospective offered by these RES systems are substantially tied to technology choice optimization and no longer solely in simple sizing. On this basis, the main goal of this work is to develop Decision Support Tools (DSSs) for energy optimization both for PV and BP plants. A first study was focused on the analysis of PV plants installed in the same farm. The aim is to examine the impact each plant component has on the PV generator global efficiency and define an analytical procedure for technical parameters optimization in order to maximize the electric yield of an architectonically integrated plant compared to a ground-mounted one. Based on the economic and efficiency features of a biomethane upgrading technology set, a second study was carried out with the aim to design a DSS to assess enterprise-wide profit margins resulting from the on-farm BP plant installation linked to the natural gas grid. The results of the two studies have shown how these DSSs can be useful tools for choosing PV and BP technologies based on farm characteristics.
4
Allison, Helen Elizabeth. "Linked social-ecological systems: A case study of the resilience of the Western Australian agricultural region". Thesis, Allison, Helen Elizabeth (2003) Linked social-ecological systems: A case study of the resilience of the Western Australian agricultural region. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/60/.
Testo completoAbstract (sommario):
In the Western Australian agricultural region, an area of approximately 14 million hectares (70,000 square miles), widespread areas of native vegetation have been cleared and replaced with annual cropping systems, predominantly wheat. Only 1.3 million hectares (10%) of small and scattered native vegetation remnants remain. By 2000 16% of land in the region was at risk from soil salinity and was largely unproductive for commercial agriculture. A new hydrological equilibrium affecting 33% of the Western Australian agricultural region is predicted to be reached between 2050 and 2300. The starting premise of this dissertation is that normal disciplinary science was adopted as the dominant intellectual influence on natural resource management policy and thus natural resource degradation was treated as a problem for science, extracted from its social, economic and historical contexts. The second premise of this dissertation is that natural resource problems are not isolated scientific or technical problems, and are exacerbated by human failure to predict the complex inter-relationships among the social, ecological and economic systems.
This dissertation initially provides an analytical narrative on the Western Australian agricultural region between 1889 and 2003 (114 years) with the main finding being that in the years pre-1970 a development-driven Western Australian Government was responsible for extensive land clearing for agriculture, often contrary to scientific advice. In the 1980s and 1990s the severity and extent of soil salinity and the prognosis of future negative trends in other natural resource indicators caused a rapid proliferation and evolution of Federal and State policies designed to 'solve the problem'. Nonetheless many natural resource problems remain intractable. The second part of the dissertation investigates the epistemology of the normal science paradigm as it was applied to natural resource management problems in the 20th century as a potentially contributing cause. The evolution of an alternative epistemology, post-normal science paradigm, is then examined for explicating our current understanding of 'reality'. A research framework was constructed which defines the post-normal science paradigm; the systemic approach; the bodies of theory-organisational, ecology, resilience and system dynamics theory; the social-ecological system perspective; and the methods-resilience analysis and system dynamics. This framework provides a novel way in which to gain a greater understanding of the fundamental or root causes of natural resource management problems. Using the case study of the Western Australian agricultural region a dynamic model was constructed based on descriptive information. An examination of the historical events and processes of the Western Australian agricultural region reveals that over a 114-year history it has evolved through two interactions of the adaptive cycle. Further investigation reveals these two cycles were synchronous with the second and third economic long-wave cycles or Kondratiev Cycles, that show the behaviour over time of the evolution of modern industrial societies. The model suggests that the reasons for the dynamic behaviour of the Western Australian agricultural region lie in the interaction of the three production growth drivers of the international commodity system, which have resulted in a pathological system, the 'Lock-in Trap'. Increased total commodity production, reinvestment and declining prices in real terms have tended to produce the unintended negative impacts of resource decline, environmental pollution and rural population decline. I suggest that the expansion of thresholds through the reinvestment in technology is a principle reason why there has not yet been a profound collapse of exploited renewable resources in the Western Australian agricultural region. Regional natural resource management strategies will need to take account of not only spatial cross-scale issues, in particular the linkages between the individual farmer and the international commodity system, but also the temporal variables, in particular the slowly emerging changes in ecological/physical variables, such as the hydrological cycle.
This research can help to provide the information and heuristic metaphors to encourage natural resource policy makers to take long-term and whole system perspectives. It includes a powerful set of tools for communicating dynamic processes in an integrated method to inform policy and management decisions. The ideas in this interdisciplinary research are essential for making science relevant within a social and ecological context.
5
Allison, Helen Elizabeth. "Linked social-ecological systems : a case study of the resilience of the Western Australian agricultural region /". Access via Murdoch University Digital Theses Project, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040730.144640.
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6
Alhamidi, Sameer K. "New directions towards sustainability of agricultural systems /". Alnarp : Dept. of Crop Science, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a425-ab.html.
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7
Campana, Pietro Elia. "PV water pumping systems for agricultural applications". Doctoral thesis, Mälardalens högskola, Framtidens energi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-27641.
Testo completoAbstract (sommario):
Grassland and farmland degradation is considered as one of the worst environmental and economic threats for China. The degradation process negatively affects food and water security, economy, society and climate changes. Photovoltaic water pumping (PVWP) technology for irrigation is an innovative and sustainable solution to curb the grassland degradation. At the same time it can promote the conservation of farmland, especially in remote areas of China. The combination of PVWP technology with water saving irrigation techniques and sustainable management of the groundwater resources can lead to several benefits. These include enhancing grassland productivity, halting wind and rainfall erosion, providing higher incomes and better living conditions for farmers. This doctoral thesis aims to bridge the current knowledge gaps, optimize system implementation and prevent system failures. This work represents thus a step forward to solve the current and future nexus between energy, water and food security in China, using PVWP technology for irrigation. Models for the dynamic simulations of PVWP systems, irrigation water requirements (IWR) and crop response to water have been presented and integrated. Field measurements at a pilot PVWP system in Inner Mongolia have been conducted to analyse the reliability of the models adopted. A revision of the traditional design approaches and a new optimization procedure based on a genetic algorithm (GA) have been proposed to guarantee the match between IWR and water supply, to minimize the system failures and to maximize crop productivity and thus the PVWP system profitability and effectiveness. Several economic analyses have been conducted to establish the most cost effective solution for irrigation and to evaluate the project profitability. The possible benefits generated by the PVWP system implementation have been highlighted, as well as the effects of the most sensitive parameters, such as forage price and incentives. The results show that PVWP system represents the best technical and economic solution to provide water for irrigation in the remote areas compared to other traditional water pumping technologies. The environmental benefits have been also addressed, evaluating the CO2 emissions saving achievable from the PVWP system operation. The assessment of the feasible and optimal areas for implementing PVWP systems in China has been conducted using spatial analysis and an optimization tool for the entire supply chain of forage production. The results show that the potentials of PVWP systems in China are large. Nevertheless, the feasible and optimal locations are extremely sensitive to several environmental and economic parameters such as forage IWR, groundwater depth, and CO2 credits that need to be carefully taken into account in the planning process. Although this doctoral thesis has used China as case study, PVWP technology can be applied for irrigation purposes all over the world both for off- and on-grid applications leading to several economic and environmental benefits.
8
Sutti, Flavio. "Importance Of Agricultural Systems As Multifunctional Landscapes". ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/485.
Testo completoAbstract (sommario):
Agricultural landscapes provide our society with many benefits. While food production is the primary role of these landscapes, sociocultural and ecological benefits are also provided. However, the full scope of benefits that we obtain from agricultural landscapes are not always taken into account, and with the intensification of agricultural activities, more complex multifunctional landscapes are converted into simpler and less-functional landscapes. I used a heterogeneous agricultural landscape, the Champlain Valley of Vermont, as a case study to examine the interactions between landscape structure and the provision of landscape functions and services.
I analyzed sociocultural and production functions indices obtained via standardized landowner surveys, and ecological function indices collected in the field for 51 plots. Plots were clustered into landscape composition categories (forest, mixed and agriculture), and configuration categories (simple and complex).
I identified a tradeoff between the production and ecological function in agricultural landscapes. When a rural landscape was managed for intensive agricultural production, ecological benefits decreased. Landscapes with diversified land use/land cover and heterogeneously distributed elements returned the greatest number of benefits. Agricultural areas that comprise between 30 and 45% of the landscape can prevent the loss of ecological benefits while retaining high production.
I evaluated the importance of treed habitats in agricultural landscapes in maintaining biodiversity. I related landscape metrics to ecological function indices obtained from fine-grained land use/land cover maps. Metrics obtained from fine-grained maps more accurately predicted the abundance of edge tolerant birds than those obtained from coarse grained maps.
I also explored the importance of small treed landscape elements for common breeding birds and evaluated the convenience of monitoring nests comparing temperature loggers to direct observations. More heterogeneous landscapes, rich in small treed elements, supported a greater density of nests. Nests located on small treed elements in agricultural landscapes were as successful as nests located in large landscape elements.
These analyses deepen our knowledge about the relationship between landscape structure and function, facilitating the evaluation of the functionality of heterogeneous agricultural landscapes.
9
Penfold, Christopher Morant. "The relative sustainability of organic, biodynamic, integrated and conventional broadacre farming systems in Southern Australia /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09AS/09asp3984.pdf.
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10
DuBose, Jennifer Robin. "Sustainability as an inherently contextual concept : some lessons from agricultural development". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/29567.
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11
Söderström, Douglas. "Comparing pre-trained CNN models on agricultural machines". Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185333.
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12
Lawal, Najib. "Modelling and multivariate data analysis of agricultural systems". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/modelling-and-multivariate-data-analysis-of-agricultural-systems(f6b86e69-5cff-4ffb-a696-418662ecd694).html.
Testo completoAbstract (sommario):
The broader research area investigated during this programme was conceived from a goal to contribute towards solving the challenge of food security in the 21st century through the reduction of crop loss and minimisation of fungicide use. This is aimed to be achieved through the introduction of an empirical approach to agricultural disease monitoring. In line with this, the SYIELD project, initiated by a consortium involving University of Manchester and Syngenta, among others, proposed a novel biosensor design that can electrochemically detect viable airborne pathogens by exploiting the biology of plant-pathogen interaction. This approach offers improvement on the inefficient and largely experimental methods currently used. Within this context, this PhD focused on the adoption of multidisciplinary methods to address three key objectives that are central to the success of the SYIELD project: local spore ingress near canopies, the evaluation of a suitable model that can describe spore transport, and multivariate analysis of the potential monitoring network built from these biosensors. The local transport of spores was first investigated by carrying out a field trial experiment at Rothamsted Research UK in order to investigate spore ingress in OSR canopies, generate reliable data for testing the prototype biosensor, and evaluate a trajectory model. During the experiment, spores were air-sampled and quantified using established manual detection methods. Results showed that the manual methods, such as colourimetric detection are more sensitive than the proposed biosensor, suggesting the proxy measurement mechanism used by the biosensor may not be reliable in live deployments where spores are likely to be contaminated by impurities and other inhibitors of oxalic acid production. Spores quantified using the more reliable quantitative Polymerase Chain Reaction proved informative and provided novel of data of high experimental value. The dispersal of this data was found to fit a power decay law, a finding that is consistent with experiments in other crops. In the second area investigated, a 3D backward Lagrangian Stochastic model was parameterised and evaluated with the field trial data. The bLS model, parameterised with Monin-Obukhov Similarity Theory (MOST) variables showed good agreement with experimental data and compared favourably in terms of performance statistics with a recent application of an LS model in a maize canopy. Results obtained from the model were found to be more accurate above the canopy than below it. This was attributed to a higher error during initialisation of release velocities below the canopy. Overall, the bLS model performed well and demonstrated suitability for adoption in estimating above-canopy spore concentration profiles which can further be used for designing efficient deployment strategies. The final area of focus was the monitoring of a potential biosensor network. A novel framework based on Multivariate Statistical Process Control concepts was proposed and applied to data from a pollution-monitoring network. The main limitation of traditional MSPC in spatial data applications was identified as a lack of spatial awareness by the PCA model when considering correlation breakdowns caused by an incoming erroneous observation. This resulted in misclassification of healthy measurements as erroneous. The proposed Kriging-augmented MSPC approach was able to incorporate this capability and significantly reduce the number of false alarms.
13
Tungate, Kimberly Denise. "Environmental factors influencing weed interference in agricultural systems". NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-07072004-001526/.
Testo completoAbstract (sommario):
In all agricultural systems using few or no herbicides, cultural and mechanical techniques are crucial to economic viability. Further advances in non-chemical weed control will require in-depth knowledge of weed biology. The objective of new strategies likely will be to alter competitive interactions between crop and weed species. An important part of weed biology, and often the basis for competitiveness, is species response to the environment. Environmental conditions differ greatly in different parts of the world. In agricultural systems, the low nitrogen status of some soils requires most crops to be amended. Weed populations can experience a wide range of fertilization regimes from year to year due to different crop rotations. Fertilization patterns in a rotation can lead to differential growth and reproductive performance of weeds and competitiveness with crops. In research described in the first two chapters, we attempt to determine the extent that lowering parental nutrition would impact weed growth, reproduction, and offspring vigor. The purpose was to begin evaluating benefits of controlling nitrogen fertility in agronomic systems on low fertility soils. Another environmental factor that could influence weed competitiveness is temperature. The significance of temperature responses will become increasingly important in the future. Global climate change models are predicting increases in the earth?s average surface temperature between 1.4- 5.8 ºC during the 21st century. As temperatures increase it is conceivable that warmer temperatures will alter competitive balance between crop and weed species, intensifying weed pressures. The expression of temperature response also will be a function of other interacting factors such as the ability to acquire water and nutrients. Resource acquisition is controlled to a large extent by root growth and interactions with soil microorganisms. The third chapter of this thesis is focused on temperature responses of selected plant species from an agroecological system. The purpose was to begin assessment of possible climate change effects on weed competitiveness. All of our experiments made extensive use of the weed Senna obtusifolia due to its importance in crops in the Southeastern U.S.
14
Bastien, Charlotte. "Pesticide levels in agricultural drainage systems in Quebec". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60528.
Testo completoAbstract (sommario):
A study was conducted to measure pesticide concentrations from two tile-drained potato fields in Saint-Leonard d'Aston, Quebec. Soil and water samples were analysed for the pesticides metribuzin, fenvalerate and aldicarb in 1989, and for metribuzin and phorate in 1990.Metribuzin concentrations up to 3.47 $ mu$g/l were detected in the tile drain water. Surface runoff samples had metribuzin concentrations up to 47.086 $ mu$g/l. Aldicarb was not detected in any of the water samples. Fenvalerate was detected in surface runoff at a level of 0.05 $ mu$g/l during the 1989 growing season. Phorate was not detected in subsurface drain water in the 1990 growing season.
Pesticide levels were higher in the surface soil layer (0-5 cm), than at 25 cm depth. Fenvalerate was detected at a level of 0.013 $ mu$g/g in the surface (0-5 cm) soil samples. Phorate concentrations of up to 0.020 $ mu$g/g were detected in soil samples. Aldicarb was not detected in the soil samples. Metribuzin was found mostly in the soil surface layer with concentrations of up to 0.23 $ mu$g/g during the 1990 growing season.
15
Loader, Rupert John. "Investigating and assessing agricultural and food marketing systems". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259511.
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16
Lottes, Philipp [Verfasser]. "Plant Classification Systems for Agricultural Robots / Philipp Lottes". Bonn : Universitäts- und Landesbibliothek Bonn, 2021. http://d-nb.info/1230878637/34.
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17
Hartmann, Marco. "Integrated farming systems for agricultural development the case of integrated agriculture aquaculture on Palawan, Philippines". Aachen Shaker, 2008. http://d-nb.info/992686547/04.
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18
Cromwell, Jeff B. "Chaotic price dynamics of agricultural commodities". Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3625.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains vi, 166 p. : ill. Includes abstract. Includes bibliographical references (p. 142-160).
19
Rocka, Timothy Dee. "Future agricultural systems competencies of beginning Texas agricultural science teachers as determined by agricultural education professionals and administrators of agricultural education programs a Delphi study /". Diss., Texas A&M University, 2003. http://hdl.handle.net/1969/174.
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20
Buckley, Mark C. Buckley Mark C. "The problem of restoring natural systems among social systems : strategic considerations and the Sacramento River /". Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.
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21
Abdulhussain, Mohamed Fidahussain 1964. "Gravity bubbler irrigation systems on steep slopes converted to bench terraces". Thesis, The University of Arizona, 1994. http://hdl.handle.net/10150/278410.
Testo completoAbstract (sommario):
Gravity bubbler irrigation is a new mode of irrigation activated by the existing pressure in conventional irrigation supply channels. In gravity flow systems on steep slopes, pressure increases in the downstream sections of the pipe and must be dissipated for uniform application. A design procedure for gravity bubbler irrigation systems on inclined steep slopes or converted to bench terrace systems is described in detail. The design is based on the use of orifices as energy dissipating devices. Laboratory tests were conducted to determine graphical relationships and coefficients for estimating the head loss for an orifice made from PVC. The head loss coefficient is a function of the orifice to pipe diameter ratio and can be expressed by an equation of the form Ko = abetab where a and b are constants determined from test data and beta is the ratio of diameters. A prototype gravity bubbler irrigation system was designed and installed.
22
Mallory, Ellen B. "Crop/Livestock Integration Effects on Soil Quality, Crop Production, and Soil Nitrogen Dynamics". Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/MalloryEB2007.pdf.
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23
Smith, Derik Lafayette, e Satya Prakash Dhavala. "Using big data for decisions in agricultural supply chain". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81106.
Testo completoAbstract (sommario):
Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 53-54).
Agriculture is an industry where historical and current data abound. This paper investigates the numerous data sources available in the agricultural field and analyzes them for usage in supply chain improvement. We identified certain applicable data and investigated methods of using this data to make better supply chain decisions within the agricultural chemical distribution chain. We identified a specific product, AgChem, for this study. AgChem, like many agricultural chemicals, is forecasted and produced months in advance of a very short sales window. With improved demand forecasting based on abundantly-available data, Dow AgroSciences, the manufacturer of AgChem, can make better production and distribution decisions. We analyzed various data to identify factors that influence AgChem sales. Many of these factors relate to corn production since AgChem is generally used with corn crops. Using regression models, we identified leading indicators that assist to forecast future demand of the product. We developed three regressions models to forecast demand on various horizons. The first model identified that the price of corn and price of fertilizer affect the annual, nation-wide demand for the product. The second model explains expected geographic distribution of this annual demand. It shows that the number of retailers in an area is correlated to the total annual demand in that area. The model also quantifies the relationship between the sales in the first few weeks of the season, and the total sales for the season. And the third model serves as a short-term, demand-sensing tool to predict the timing of the demand within certain geographies. We found that weather conditions and the timing of harvest affect when AgChem sales occur. With these models, Dow AgroSciences has a better understanding of how external factors influence the sale of AgChem. With this new understanding, they can make better decisions about the distribution of the product and position inventory in a timely manner at the source of demand.
by Derik Lafayette Smith and Satya Prakash Dhavala.
M.Eng.in Logistics
24
Sherif, Souad Mohammed. "The economic feasibility of introducing aquaculture into traditional farming systems in Arizona". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288781.
Testo completoAbstract (sommario):
The primary objective of this study was to evaluate the economic feasibility of introducing fish culture into irrigated cotton production on farms in central Arizona. The representative farm adopted in this study is a cotton farm described in Arizona Field Crop Budgets, 1994-95. The only adjustment necessary for the farmer to make is to keep water in the ditches at all times. Water as a production variable for fish production was thus calculated only for the additional quantity required. Analysis of these production systems was accomplished by budgeting procedures as well as statistical analysis. The economic-engineering (synthetic firm technique) was employed to develop the input-output coefficients necessary for analysis. Five fish densities and eight ditch capacities were tested. The production function was estimated using input and yield data. Three functional forms (linear, quadratic and Cobb-Douglas) were examined to determine how well they estimated the production system. Using budget analysis, a fish stocking density of six fish per cubic meter and a ditch capacity of 2,925 m3 appear to provide the optimal production scenario, if the percentage of fish reaching harvestable size is improved from 66 percent to at least 80 percent. This density has been proven to require minimum production costs and to provide the most efficient use of resources. However, production functions estimated in this study indicate that profits can be increased through additional use of feed. At any ditch capacity, a density of six fish per cubic meter, provides the optimal economic results, MVP = PX2 Finally, the implication of the findings of this study are that raising tilapia in irrigation ditch systems on cotton farms in central Arizona is feasible at a stocking density of six fish per cubic meter. Studies to improve the percentage of fish reaching marketable size at this density is very critical. Increasing the initial size of the fingerlings could be a consideration in improving the percentage of fish reaching marketable size and eventually increasing optimum economic returns.
25
Thompson, Iris Lee. "Agricultural Systems in Babati : Zea mays and its alternatives". Thesis, Södertörn University College, School of Life Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-2660.
Testo completoAbstract (sommario):
This paper aims to give an understanding on the aspects that influences the choice of cropsand agricultural methods in Babati, Tanzania. Drought is a reoccurring problem in this part ofTanzania, which affects a majority of the towns’ farmers. This fact is likely to affect thechoice of crop as well as the limitations when it comes to the choices in cultivation. But thechoice itself has implications on its surrounding and can be affected by the surrounding. Tounderstand the circumstances, a wider picture will be depicted and an evaluation of thegeography of Babati and on its climate conditions. The results from this study suggest thatlack of crop rotation pose as a problem that should be studied. Furthermore, green manurefrom legumes and plants like Tithonia could be a less expensive alternative but can stillfunction as an effective fertilizer. Concerning the drought issue the study can not concludethat drought resistant crops would have any big improving effects. Nevertheless there is someevidence advocating that it could be apart of the solution in terms of avoiding some of thenegative effects brought on by drought.
26
Erdil, Erkan. "Demand Systems For Agricultural Products In The Oecd Countries". Phd thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12604825/index.pdf.
Testo completoAbstract (sommario):
The estimation of demand equations provides the earliest example of the use
of statistical and econometric techniques on economic data. It is possible to identify
two distinct approaches to the estimation of demand equations. The first and
original approach concentrated on the demand for particular goods by paying
attention to any special characteristics of the single market involved. The second
approach involved simultaneous estimation of complete systems containing the
demand equations for every commodity group purchased by consumers. The
estimation of a complete system of demand equations in principle enables us to
obtain better estimates of each equation in the system than the first approach
because of interaction in the demand behavior of different commodities. This study
is directed towards the estimation of demand systems for agricultural products in
the OECD countries. Three representatives demand systems with their extensions,
namely the Rotterdam Model, An Almost Ideal Demand System (AIDS), and CBS
model are used. These models are estimated by Seemingly Unrelated Regression
(SUR) method. The procedures to estimate demand systems suggest significant
empirical regularities for agricultural products in the OECD countries. The main
contribution of this study is its procedure for model selection. This procedure
implies the superiority of AIDS and CBS models over the Rotterdam model.
27
Röing, Kristina. "Soil nitrogen fluxes in Swedish and Nigerian agricultural systems /". Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200557.pdf.
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Nicholson, Fiona Annabel. "Anthropogenic influences on cadmium in agricultural soil-plant systems". Thesis, Lancaster University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309024.
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Velasco, Joel. "Nitrogen dynamics in integrated agricultural systems in central Mexico". Thesis, University of Plymouth, 2009. http://hdl.handle.net/10026.1/2458.
Testo completoAbstract (sommario):
Smallholdings (<5 ha) represent 73% of the total agricultural production systems in Mexico. Many are of low productivity, and little quantitative data has been published on the impact of traditional nitrogen (N) management practices on environmental performance at farm scale. Nitrogen is the most important nutrient for increasing crop yields. While the benefits from the use of N fertilizer are self evident, it has resulted in low efficiency of N utilization and environmental problems. This project aimed to assess N dynamics in Integrated Agricultural Systems (lASs) in central Mexico. Nitrogen inputs, outputs and internal transfers were assessed and the impact of selected management practices on nitrogen flow, productivity and environmental performance were analyzed using nitrogen use efficiency (NUE) indices. A predictive framework tool was developed following whole farm methodologies to quantify N flow, and to assess selected (NUE) indices such as 0/1 ratio, N loss, accumulated N, and the change of N in the soil pool at farm scale. Data used for the development of the predictive framework was derived from experimental evaluations of ammonia emissions during vermicomposting, and integrated with data from the literature, together with data from an integrated agricultural systems prototype in Montecillo Mexico. The main N inputs into integrated agricultural systems in the Texcoco region were estimated to be in the following order of significance: biological N fixation (11 - 532), manure (15 - 225), fertilizer (0 - 140) and rainfall water (30 - 35 kg haˉ¹ aˉ¹). The main N outputs were: N losses (70 - 528 kg haˉ¹ aˉ¹) and exported N in marketable products (72 - 338 kg haˉ¹ aˉ¹). Experimentally derived estimates of ammonia emissions during vermicomposting of sheep manure ranged from 10 - 15 kg Mgˉ¹ DM which corresponded to 42 - 47% of the initial N content in the manure substrate. The impact of current management practices showed 0/1 ratios ranging from 0.30 - 0. 76, N losses ranged from 76 to 210 kg haˉ¹ aˉ¹ and N depletion/ accumulation ranged from -25 - 143 kg haˉ¹ aˉ¹. The effect of selected management practices on 0/1 ratio was as follows: crop sequence > stocking density > livestock type > manure management. Whereas for N loss it was stocking density > livestock type > manure management > crop sequence. Higher productivity together with a more benign environmental impact could be attained in smallholder by implementing simple recommended manure management practices at farm scale.
30
Gibson, Simon. "Landscape archaeology and ancient agricultural field systems in Palestine". Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440425.
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31
Sheler, Rebecca Joy. "The impact of agricultural drainage systems on hydrologic responses". Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/2630.
Testo completoAbstract (sommario):
Over the past century of settlement, the landscapes of the Midwestern United States have experienced extensive anthropogenic modifications in order to convert prior wetlands-lowlands to subsequent fruitful croplands. The hydrologic responses of these landscapes have been significantly altered by the installation of artificial drainage (surface ditches and subsurface tile drains) and the change in natural preferential flow paths (increased cracks or root holes due to land use practices). Changes to peak stream flow behaviors is a result of many different inter-related variables; however, intensified agricultural drainage remains one of the largest suspects. Though the effects of subsurface drainage (primarily in the form of tile drains) on landscape, hydrology, ecology, and economy have been questioned, theories of hydrologic controls continue to be vague at best. Soil-Water-Atmosphere-Plant, known as SWAP, was developed to simulate the interaction of vegetation development with the transport of water, solutes, and heat in the unsaturated zone. It is a one-dimensional, vertically directed model with a domain reaching from a plane just above the canopy to a plane in the shallow saturated zone. In the horizontal direction, the model's main focus is the field scale since most transport processes can be described in a deterministic way. The SWAP model was calibrated and validated for simulating flow regimes of drained and undrained landscapes in Iowa. A new term `flashiness' is used to characterize flow data. The Richards-Baker Flashiness Index quantifies the frequency and intensity of short term changes in streamflow. From the simulated results, the effect of anthropomorphic modifications to a landscape is determined to be strongly influenced by soil structural properties and hydraulic properties, along with rainfall regimes. Adding subsurface drains to soils with lower hydraulic conductivities, such as clay, tends to reduce peak flows during precipitation events. Conversely, adding drainage to soils with higher hydraulic conductivities, such as sand, increases peak flows. During years with heavy precipitation, soils with lower permeability show a `saddle shape' relationship between the flashiness index and the distance between tile drains produces. The lowest point of the `saddle' determines the ideal drain spacing for mitigating flashiness. When the shrinking and cracking of clay soils is considered, macropores dominate water flow pathways into the soil matrix and tile drains have a minimal effect on the flow regime. The volume of macropores at the surface of the soil profile is indirectly proportional to flashiness index. Independent of rainfall regimes, cropping season, and soil type, subsurface flows of drained landscapes always exceed that of undrained landscapes. Continuance of comprehensive studies of artificial subsurface drainage can produce positive impacts on engineering, economic, and ecological environments.
32
Salvato, M. "Performance of wetland systems in reducing agricultural nitrogen pollution". Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426572.
Testo completoAbstract (sommario):
The thesis is about the performance of wetland systems in reducing agricultural nitrogen pollution. It takes into account two experiments at different scale: a 3200 m2 pilot surface wetland and a mesocosm trial.
In the first case the aim was to evaluate the performance of the wetland, located at the experimental farm of the University of Padova (Italy), in abating nitrogen coming from 5 ha of surrounding fields. Overall, for the entire period (2.5 years), the basin performed well in abating both nitrate and total nitrogen with a removal efficiency of about 90%.
The major quantity of removed nitrogen was stored in vegetation and soil and only 6% was estimated as being lost with denitrification.
In the mesocosm experiment the aim was to compare five different species in abating nitrogen coming from a reconstructed wastewater. The experimental setup consisted of plastic tanks, filled with gravel and vegetated with Carex elata All., Juncus effusus L., Typhoides arundinacea (L.) Moench var. picta, Phragmites australis (Cav.) Trin. and Typha latifolia L.. There was also a control without vegetation. A solution of increasing concentrations of NH4-N and NO3-N was applied to the tanks, over 31 cycles of differing lengths. At the end of each cycle exiting water was analysed to determine the two nitrogen forms. All water volumes entering and exiting the tanks were measured in order to evaluate evapotranspiration. At the end of the trials T. latifolia had removed 82% of the entering nitrogen, followed by T. arundinacea (76%), C. elata (75%), Ph. australis (72%) and J. effusus (64%). The control removed 45% of the entering nitrogen. The fate of the two forms of nitrogen differed as NH4-N disappeared almost completely and in short time in all the treatments while NO3-N showed different removal efficiency depending on season and considered species.
The major quantity of entering nitrogen was stored in plant tissues with different percentages depending on species. The calculated denitrification varied from 18% for J. effusus to 37% for T. arundinacea.Il lavoro è consistito nello studio dell’efficienza delle zone umide costruite nel ridurre l’azoto proveniente dall’inquinamento di origine agricola. La tesi prende in considerazione due prove sperimentali a diversa scala nel triennio 2007-2009: una zona umida a flusso superficiale di 3200 m2 e una prova a scala di mesocosmo. Nel primo caso l’obiettivo era di valutare l’efficienza della zona umida sita presso l’azienda agraria sperimentale dell’Università degli Studi di Padova, nell’abbattere azoto proveniente da 5 ha di circostante terreno coltivato. Alla fine del periodo considerato (2.5 anni) il bacino ha dimostrato di abbattere molto bene sia l’azoto nitrico che totale con efficienze di rimozione introno al 90%. La maggior parte dell’azoto in entrata è stata immagazzinata nel comprato suolo/vegetazione mentre la denitrificazione è stata stimata pari al 6%. Nella prova a scala di mesocosmo l’obiettivo era di comparare l’efficienza di rimozione dell’azoto di cinque diverse specie. L’impianto sperimentale era costituito da vasche in plastica riempite di ghiaia e vegetate con Carex elata All., Juncus effusus L., Typhoides arundinacea (L.) Moench var. picta, Phragmites australis (Cav.) Trin., and Typha latifolia L.. Era presente anche un controllo non vegetato. Una soluzione con concentrazioni crescenti di NH4-N and NO3-N è stata applicata alle vasche effettuando 31 cicli di diversa durata. Alla fine di ogni ciclo l’acqua in uscita dalle vasche è stata analizzata per azoto nitrico e ammoniacale. I volumi di acqua in entrata e uscita sono stati misurati al fine di calcolare l’evapotraspirazione. Considerando tutti e tre gli anni di prova, Typha latifolia L. ha rimosso l’82% dell’azoto in entrata seguita da Typhoides arundinacea (L.) Moench (76%), var. picta, Carex elata All. (75%), Phragmites australis (Cav.) Trin., (72%) e Juncus effusus L. (64%). Il controllo non vegetato ha rimosso invece il 45%. Azoto ammoniacale e nitrico hanno presentato diverse dinamiche di scomparsa. Il primo è stato abbattuto quasi completamente e in breve tempo in tutti i trattamenti, il secondo invece è stato rimosso in maniera diversa a seconda della stagione e della specie considerata. La maggior quantità di azoto in entrata è stata immagazzinata nei tessuti con percentuali diverse secondo le specie. La denitrificazione calcolata varia dal 18% in Juncus effusus L. al 37% in Typhoides arundinacea (L.) Moench var.picta.
33
Makhwaje, Ernest N. "Strategic planning of agricultural land information systems in South Africa". Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1113.
Testo completoAbstract (sommario):
Thesis (PhD(Agric) (Agricultural Economics))--Stellenbosch University, 2008.The planning processes involved in the design and development of strategic land information systems in a semantic context require a logical approach. An array of efficacy problems associated with the relevance of the information required and the data to be provided must be dealt with in terms of this logical approach so that wise decisions can be made about future land resource use options. This study applies the aforementioned statement to strategic decision-making regarding information management in the provision of accurate and relevant information about the characteristics of the land resource for use by both the public and private sectors in South Africa. With ever evolving human needs that increase pressure on the limited land resource, the need for accurate and relevant information for strategic purposes is increasing. However, even at the present time, land information systems design and development is characterised by a technical design orientation and a narrow cost-efficiency focus, with a lack of strategic envisioning. Strategic decisions require effective choices regarding what data should be collected and how this should be stored and processed to support landresource- use decisions in the future. Information systems can, however, not cater for too many variables due to cost implications. Hence, strategic choices in generating only the required information and data for storage and processing become necessary.
34
Cowley, Robyn Anne. "The effect of changing water distribution from linear to point source on vegetation and soil following piping of an artesian bore in a semi-arid mulga paddock /". [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16636.pdf.
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35
Colaizzi, Paul Dominic 1968. "Overwatering controller for landscape irrigation systems". Thesis, The University of Arizona, 1997. http://hdl.handle.net/10150/278585.
Testo completoAbstract (sommario):
Water conservation in metropolitan areas of Arizona is critical if limited water resources are to meet current and future demands. Timer controlled landscape irrigation systems contribute to a large portion of municipal water use, and there is currently a great potential for water savings when deficit irrigation is practiced. Such systems tend to forfeit deficit irrigation by overwatering vegetation; however, deficit irrigation may be improved if the number of irrigation cycles are reduced based on sensing soil water in the plant root zone. A patent pending electronic circuit, called the overwatering controller, has been developed and tested for this purpose. Test results show the overwatering controller has great potential as a water conservation and deficit irrigation management tool.
36
Zhu, Minkang. "A multiple objective approach to evaluate economic and environmental impacts of agricultural management systems from a sustainable development perspective". Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/38786.
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37
Gebre-Selassie, Samuel. "The development of integrated management information systems for agricultural extension institutions of developing countries : the case of Oromia Agricultural Development Bureau of Ethiopia /". Aachen : Shaker, 2001. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=009323076&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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38
Yanti, Nuri Dewi. "Sustainability analysis of farming systems in tidal swamplands : a case study in South Kalimantan, Indonesia". University of Western Australia. School of Agricultural and Resource Economics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0218.
Testo completoAbstract (sommario):
[Truncated abstract] The initial success of the Green Revolution notwithstanding, the ability of our planet to produce sufficient food to support its growing population is causing growing concern. Indonesia, like many other countries, cannot produce sufficient rice to feed its people. This creates an imperative to import rice that Indonesia wishes to overcome. In addition, agricultural intensification has created ecological contamination from overuse and the mismanagement of chemical inputs. These problems threaten the sustainability of agricultural lands and Indonesia's ability to support national food selfsufficiency. The extension of agricultural lands is one alternative that has been implemented by the Indonesian government for more than two decades. Families from the crowded islands of Java and Bali have been translocated to the outer islands of Kalimantan, Sulawesi, and Papua. In South Kalimantan, the tidal swampland areas are one of the resettlement destinations; which are usually reclaimed for the purpose of increasing rice production. However, the difference between the natural characteristics, socialeconomics, language, and culture in South Kalimantan, compared with the homelands of the transmigrant farmers, has the potential to adversely affect the farming activities of both the transmigrant and the local indigenous farmers. This in turn might affect the sustainability of the tidal wetlands for agricultural production. It may also damage the ecological integrity of the coastal environment ... The research findings indicate that farming practices by the groups differed significantly. Similarly, there was a significant difference between the cultivation of traditional rice varieties and the HYV. Farming practices performed by the indigenous local farmers, who have lived in the swamplands for centuries, were more ecologically sustainable than those of their transmigrant counterparts in both of the tidal swamplands being assessed. Likewise, traditional (indigenous) rice variety cultivation appears to be more sustainable than the HYVs. Among the socio-economic and agronomic influences of the farming practices selected for statistical analysis, only the non-formal education variable had a significant impact on the sustainability index. Tidal swampland Type B has lower yields than Type A, but in both swampland types, indigenous farmers produce higher yields than the transmigrant farmers, while the HYV has a higher yield over the traditional one. Indigenous farmers received higher financial returns per ha compared to the transmigrant returns in tidal swampland Type A and Type B. The higher yields produced by the HYVs are not accompanied by a higher financial return per ha compared to the traditional variety. The conclusions of this research are that not only are indigenous farming practices more sustainable but that indigenous farmers achieve a higher overall output and higher returns per ha from their farming activities. Future research should be formulated to further investigate the implications for both increasing rice production and sustainability by extending the use of indigenous farming systems. The sustainability index developed in this research should be investigated for adaptation in other areas of Indonesia and possibly by other farming areas internationally.
39
Dan-Azumi, J. J. "Agricultural sustainability of smallholder floodplain agricultural systems : a case study of Fadama areas in North-Central Nigeria". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1318073/.
Testo completoAbstract (sommario):
In the aftermath of the global food crisis, great debates have arisen on the future of African agriculture. The crisis has once again raised the question of food security on the continent. Previous approaches aimed at increasing the agricultural productivity of farmers have failed. This has necessitated a call for a change of approach in which smallholders, who are the bulk of Africa’s food producers, will play a pivotal role. The main challenge facing the continent is how to balance the quest for food self-sufficiency and the demands of sustainability. This thesis is a concrete contribution in the quest for productive yet sustainable food systems in Africa. It surveys and analyses the sustainability of fadama (floodplains) farming systems of Northern Nigeria. Strong emphasis is placed on the socio-economic, institutional and demographic drivers affecting productivity and sustainability of fadama agriculture. Findings reveal a delicate interaction and negotiation across the formal and informal boundaries where traditional agricultural practices, based on an understanding of the particular physical reality and exploitation of natural synergies, are combined with inputs typical of conventional agriculture. African agriculture thus stands poised at crossroads; whether to abandon tradition in favour of entirely ‘modern’ methods and export markets as often advocated for in certain circles or depend on time tested indigenous knowledge systems and grassroots-defined development vision which combines popular livelihoods with respect for nature’s systems. Drawing on Bruno Latour, the metaphor of ‘hybridisation’ is used to justify a negotiated compromise between official discourses, which promote the use of chemicals and grassroots reality which relies on nature’s systems. Agroecology is offered as a model to overcome this agricultural dualism (inputs vs. tradition) through combining compatible elements of the two systems for greater productivity and sustainability. However, the key question of how agricultural hybridization should take place remains unresolved in this thesis for whereas it appears feasible in certain areas such as knowledge and institution sharing, in others such as the use of external inputs, the two systems appear irreconcilable.
40
Hartmann, Marco [Verfasser]. "Integrated Farming Systems for Agricultural Development : The Case of Integrated Agriculture Aquaculture on Palawan, Philippines / Marco Hartmann". Aachen : Shaker, 2009. http://d-nb.info/1161311246/34.
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41
Siebert, Stefan. "Analysis of arid agricultural systems using quantitative image analysis, modeling and geographical information systems". Kassel : Kassel Univ. Press, 2006. http://nbn-resolving.de/urn:nbn:de:0002-1929.
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42
Siebert, Stefan. "Analysis of arid agricultural systems using quantitative image analysis, modeling and geographical information systems". Kassel Kassel Univ. Press, 2005. http://deposit.d-nb.de/cgi-bin/dokserv?idn=982924984.
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43
Krusekopf, Charles C. "Land-tenure institutions and agricultural productivity in post-reform China /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/7460.
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44
Meng, Chao. "Simulation-Based Decision Support For Agricultural Supply Chain Performance Improvement". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/581318.
Testo completoAbstract (sommario):
Grafted vegetable seedlings have been proven to possess higher seed/non-seed diseases resistance and yields compared with non-grafted ones. Owing to the seasonality of vegetable planting and labor intensiveness of grafted seedling production (e.g., grafting operation), U.S. vegetable seedling supply chains suffer from high grafted seedling cost. To make grafted seedlings affordable for vegetable growers, low-cost production systems and cost-efficient grafting capacity must be achieved via optimal design of a grafting operation system and supply chain collaboration, respectively. Toward this end, a two-level simulation-based framework is proposed in this work for improving the overall performance of the grafted seedling supply chain by supporting both the grafted seedling production system design and supply chain collaboration decisions. The considered supply chain consists of a single grafted seedling producer that produces grafted seedlings and multiple vegetable growers that seasonally purchase grafted seedlings and produce vegetables to meet price-sensitive demand from the downstream market. More specifically, the low level of the proposed framework focuses on the grafted seedling production system design by integrating discrete event simulation (DES) together with a fuzzy analytic hierarchy process (AHP) for multiple criteria (i.e. production cost, capital investment, production throughput time, resource utilization, and product quality). A Unified Modeling Language (UML)-based simulation modeling and generation approach is developed to automatically generate simulation models of various production system design alternatives. UML information models are developed to provide the system structural information for simulation model generation, production information for simulation execution, and output requirement information for defining simulation outputs. The performance of the production system design alternatives for the aforementioned criteria is evaluated via the generated simulation models, and the corresponding simulation results together with decision makers' judgments on the criteria are used to select the best system design via AHP. A best alternative search (BAS) procedure is proposed for the adopted AHP approach to search for the best system design against ranking impreciseness caused by simulation randomness. At the high level, the proposed framework focuses on the optimal supply chain decisions for early order commitment (EOC) to reduce the amortized production capacity cost. EOC is a supply chain collaboration mechanism, where the grafted seedling producer encourages the vegetable growers to commit their orders earlier than their regular ordering times by providing certain benefits (e.g., price discount). Based on the optimal design of a grafted seedling production system and the corresponding production cost obtained at the low level, we first derive analytical solutions for the grafted seedling producer's optimal capacity, vegetable grower's optimal order quantity, and ordering time under a basic supply chain structure (i.e., single-seedling producer and single-vegetable grower). We then introduce capacity competition by extending the basic structure to a multi-vegetable grower structure. The existence of the N-person game equilibrium and the corresponding relationships between the grafted seedling producer's profit and the vegetable growers' early order decisions are provided. In addition, a capacity reservation mechanism is proposed for the seedling producer to motivate the vegetable growers to release order information in advance. To identify the convergence of the vegetable growers' ordering times, a Cellular Automata simulation model is developed, where each vegetable grower is modeled as a Pavlovian or greedy agent making an ordering time decision so as to receive the higher profit over iterations. The proposed framework is demonstrated for grafted seedling supply chains in North America. The experiment results reveal the benefits of the proposed framework in reducing the grafted seedling cost, as well as in increasing the entire supply chain's profit.
45
Frey, Beat W. "Arbuscular mycorrhizas and N-cycling in agricultural plant-soil systems /". [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10235.
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46
Macmillan, Susan. "An appraisal of wind energy conversion systems for agricultural enterprises". Thesis, Robert Gordon University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330282.
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47
Kinkaid, Eden. "The architecture of ecology: Systems design for sustainable agricultural landscapes". Ohio University Honors Tutorial College / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1366983104.
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48
Marques, Guilherme Fernandes. "Economic representation of agricultural activities in water resources systems engineering /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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49
Stump, Daryl Andrew. "Towards an applied archaeology of East African intensive agricultural systems". Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445862/.
Testo completoAbstract (sommario):
This study questions whether archaeological techniques and perspectives can be applied to aid in the assessment of rural development practices in Africa, and is a response to a gradual paradigm shift that rejects large-scale, top-down modernisation programmes in favour of small-scale projects that are managed locally and employ 'indigenous' systems of knowledge. In Africa, as in other parts of the developing world, the projects that have adopted this alternative approach have tended to focus on rural economies and have drawn upon recent research that has emphasised the unique contexts of individual communities' approaches to resource exploitation, and which have demonstrated the ability of many societies to maintain modes of economy that various western derived models would expect to be unsustainable. Although these studies have originated from a variety of disciplinary standpoints and have, in general, stressed the need for a multidisciplinary approach, archaeological data is rarely employed. Superficially, however, the case for an archaeological contribution seems self-evident, since any appraisal of sustainability clearly requires an assessment of how long a particular agronomy has been in operation, and whether or not the practices that have sustained it have changed through time. The current study explores the implications of increased archaeological involvement in this area of research by questioning whether an 'applied archaeology' of African agriculture would be theoretically desirable and pragmatically feasible. The question of desirability includes a discussion of the inevitable political implications of contributing to contemporary developmental debates, but focuses primarily on the more overtly theoretical issue of inter-epistemological translation: arguing for a return to the level of relativism espoused by early post-processualism, and adopting a shift in emphasis that incorporates the construction of plausible pasts alongside a functional approach that may offer insights of value to contemporary communities. In order to assess the feasibility of an archaeological contribution, this paper presents the findings of recent fieldwork at the late precolonial site of Engaruka, in north-eastern Tanzania. These results show that the system of terraces and irrigation features formerly employed at the site were completely integrated to produce a unique and sophisticated response to the problems of farming in this area, and demonstrate that relatively simple, and readily taught, archaeological techniques have the potential to model precisely the development and expansion of agricultural systems, and can do so over a longer period than the methods available to other disciplines. The thesis concludes, therefore, that there is a real need for a truly interdisciplinary approach to this area of study, and that such an approach should include an archaeological component.
50
Najar, Santos. "High-Speed Mobile Networks for Modern Farming and Agricultural Systems". DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1184.
Testo completoAbstract (sommario):
ABSTRACT
High-Speed Mobile Networks for Modern Farming and Agricultural Systems
J.Santos Najar-Ramirez
High-speed mobile networks are necessary for agriculture to inventory individual plant health, maximize yield and minimize the resources applied. More specifically, real-time information on individual plant status is critical to decisions regarding the management of resources reserved and expended. This necessity can be met by the availability of environmental sensors (such as humidity, temperature, and pH) whose data is kept on storage servers connected to static and mobile local area networks. These static and mobile local area networks are connected to cellular, core and satellite networks. For instance, agricultural experts remotely working on vast acreage farms from business offices or while traveling can easily connect their notebook computers and other portable devices to these networks in order to check farm status, send email, read industry news or arrange a visit to neighbor farms or suppliers. Today, several mobile phone companies offer broadband service with 2Mbps downlink in rural and dense urban areas, however, they do not typically exist in farm areas. Although these networks (such as 802.11ac/n, 3G, 4G, etc) are significant achievements, they do not meet the projected needs of the agricultural industry. The present use model of high-speed networks for email and multimedia content, together with agriculture’s expected intensive use of real-time plant and environmental condition monitoring, with statistics/plots and real-time high resolution video, necessitates a highly integrated and highly available networked system. For agricultural experts, attentive to market needs, seamless high-speed wireless communication ‘anywhere, anytime at any speed’ is critical to enhancing their productivity and crop yields.