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1
Ahmad, Muhammad Nauman. "Air pollution impacts to agricultural crops." Thesis, University of York, 2010. http://etheses.whiterose.ac.uk/1165/.
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Although air pollution levels are increasing, there is no knowledge of air pollution effects on agricultural crops in the Peshawar region of Pakistan. The aim of this study was to assess the impact of ozone (O3) and hydrogen fluoride (HF) on agricultural crops in Peshawar through a combination of field work and experiments. The mean monthly O3 concentration in Peshawar, measured using passive samplers, was between 25-30ppb in February and March, but increased to 35-55ppb in April and May; it fell to 15-20ppb in November/December. O3 injury was found on potato (black flecking), onion (leaf tipburn) and cotton (white stipples) in a survey in April/May, but was absent from many other crops. No O3 injury was found on any crops during a winter survey. O3 fumigation experiments on spinach (Beta vulgaris) and onion (Allium cepa) in open-top chambers in UK showed that high O3 concentrations can affect both species in terms of visible injury and growth. However, onion is at greater risk in the field as it is a summer crop and is likely to be exposed to high O3 concentrations, unlike spinach, which is grown in the winter season. An EDU experiment on spinach under field conditions in Peshawar showed no effect on growth during winter season. However, elemental contents of spinach were significantly reduced in EDU treated plants. The HF concentrations in Peshawar, measured using passive samplers were higher in summer than in winter in areas close to brick kiln fields. The mean summer concentration was 0.2μg HF m-3, with maximum of 0.3μg HF m-3 in May. HF was below detection limits of <0.1μg HF m-3 in November-December. Severe HF injuries to mango, apricot and plum leaves, in form of necrotic leaf margins and tipburn, were found near the brick kiln fields. Tomato, maize, wheat and sugarcane were found to be less sensitive, but also showed some HF injury. The fluoride content of fruit leaves, wheat grains and spinach was significantly higher in the brick kiln area than at control sites. There was no significant difference between the soil fluoride content of wheat fields in the brick kiln area and at control sites. Wheat grown at different NaF levels in alkaline soils similar to those in Peshawar, in a greenhouse experiment in the UK showed no effect of fluoride on growth. The degree of powdery mildew infestation increased with increased fluoride concentrations in the soil and ear emergence was also delayed in all treatments except the control. It was concluded that O3 and HF are significant pollutants in Peshawar, especially for summer crops. More detailed studies should be conducted to determine the magnitude of damage caused by these pollutants in the Peshawar region.
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Chen, Changping 1958. "Production variability for major Arizona field crops." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/291617.
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Previous variability studies in both U.S. and worldwide agriculture have indicated that crop production has been accompanied by increasing variation. In this research, four different variability indexes were estimated in order to evaluate the production variability associated with the major Arizona field crops. Results show that major Arizona field crops, which are all irrigated, did not have a uniform production variability over the last 24 years and the variability of these crops did not generally increase between the periods of 1967-1978 and 1979-1990. Although biological factors (e.g. pests, weather) influenced variability, the variation of crop production measures over time also was related to market factors (e.g. prices), government farm programs, producers' crop management experience, and the geographical area selected for the analysis. Crops covered by government farm programs usually varied more in harvested acreage and fluctuated less in yield per acre than vegetable crops.
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Weber, Norbert, and Matthias Meyer. "Land availability for sustainable agricultural tree crops." Adjacent Digital Politics Ltd, 2021. https://tud.qucosa.de/id/qucosa%3A73975.
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Prof Dr Norbert Weber from TU Dresden argues that land availability for sustainable agricultural tree crops and a positive perception of this by the official administration both remain challenging hurdles.
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Cummins, Ewen. "Risk and the agricultural household." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297755.
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Åström, Petter. "Cash crops vs food crops : A case study of household's crop choices in Babati District." Thesis, Södertörn University College, School of Life Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-2605.
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According to earlier research farmer's crop orientation in developing countries mainly depends on farm size, large-scale farmers prefer cash crop while small-scale farmers prefer subsistence crops. The first aim of this study is to see if this hypothesis can be applied on six households in Babati District in rural Tanzania. The second aim is to investigate if other factors than farm size affect crop portfolio choice and the final aim is to see if those crop portfolio models can be improved. A case-study research design and qualitative interviews are used. The primary data is based on a fieldwork that took place from the 18th of February until the 7th of March 2009 in the study area.
From a theoretical perspective the underlying assumptions of the Marcel Fafchamp's model Crop portfolio choice under multivariate risks is discussed in connection to the result of the study.
Interviews were made with six households of different farm size. The result of the study indicates that both small-scale and large-scale farmers are using cash crops. The fact that all crops can be used for selling, gives also small-scale farmers in season with higher prices, an opportunity to sell a large share of their crops. It's thereby not possible to state that large-scale farmers devote a larger share of their land for cash crop than small-scale farmers do.
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Guinan, Patrick E. "Seasonally adjusted index for projecting agricultural drought /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3164510.
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Petousi, Ioanna. "Reuse of treated domestic wastewater on Mediterranean agricultural crops." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/10167/.
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Wastewater is considered as a new and unconventional source of water for agricultural production in many arid and semi-arid countries worldwide. As a result, careful monitoring of soil and plants for a range of parameters including salts, nutrients, micro-elements, heavy metals, toxic pollutants and pathogens is required. During this study, the application of three different qualities of treated domestic wastewater on four agricultural crops was examined in Crete, Greece: a typical Mediterranean semi-arid area. Primary treated (low quality), secondary treated (medium quality) and tertiary treated (high quality) wastewater were applied to a) olive trees, b) grapevines, c) radishes and d) carnations. Tap water and fertilized tap water (controls) were also applied in all the above agricultural crops for comparison with treated wastewaters. In general, increased concentrations of sodium, phosphorus, potassium and nitrogen in soils could be observed after wastewater irrigation. High salinity and boron concentrations in treated wastewater had no adverse effect on the examined cultivations. Low quality treated wastewater should not be used for irrigation mainly due to high levels of pathogens. In addition, they were found to a) to inhibit grapevine growth b) to degrade grape quality characteristics, and c) to accumulate polycyclic aromatic hydrocarbons (PAHs) in soil and radish roots. On the other hand, high quality treated wastewater had no negative effect on soil, plant growth, health safety and fruit quality of all the examined agricultural crops. Furthermore, the application of tertiary treated wastewater a) improved leaf chlorophyll concentration and yield of grapevines, b) improved yield and fruit quality characteristics of radishes and c) improved plant growth of carnations. Finally, olive trees were found to be less sensitive to irrigation water quality suggesting that even medium-quality wastewater could be safely applied.
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Castellazzi, M. S. "Spatio-temporal modelling of crop co-existence in European agricultural landscapes." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/3747.
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The environmental risk of growing genetically modified (GM) crops and particularly the spreading of GM genes to related non-GM crops is currently a concern in European agriculture. Because the risks of contamination are linked to the spatial and temporal arrangements of crops within the landscape, scenarios of crop arrangement are required to investigate the risks and potential coexistence measures. However, until recently, only manual methods were available to create scenarios. This thesis aims to provide a flexible referenced tool to create such scenarios. The model, called LandSFACTS, is a scientific research tool which allocates crops into fields, to meet user-defined crop spatio-temporal arrangements, using an empirical and statistical approach. The control of the crop arrangements is divided into two main sections: (i) the temporal arrangement of crops: encompassing crop rotations as transition matrices (specifically-developed methodology), temporal constraints (return period of crops, forbidden crop sequences), initial crops in fields regulated by temporal patterns (specifically-developed statistical analyses) and yearly crop proportions; and (ii) the spatial arrangements of crops: encompassing possible crops in fields, crop rotation in fields regulated by spatial patterns (specifically-developed statistical analyses), and spatial constraints (separation distances between crops). The limitations imposed by the model include the size of the smallest spatial and temporal unit: only one crop is allocated per field and per year. The model has been designed to be used by researchers with agronomic knowledge of the landscape. An assessment of the model did not lead to the detection of any significant flaws and therefore the model is considered valid for the stated specifications. Following this evaluation, the model is being used to fill incomplete datasets, build up and compare scenarios of crop allocations. Within the GM coexistence context, the model could provide useful support to investigate the impact of crop arrangement and potential coexistence measures on the risk of GM contamination of crops. More informed advice could therefore be provided to decision makers on the feasibility and efficiency of coexistence measures for GM cultivation.
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Nadolnyak, Denis Alexandrovic Jr. "Three essays on the economics of agricultural biotechnology." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1058818716.
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Al-Amoud, Ahmed Ibrahim. "A water management model for trickle irrigated row crops." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292233.
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Sjöström, Åsa Elisabeth. "Uptake of nonylphenols by crops following agricultural use of sewage sludge." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414491.
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Vieira, Carlos Antonio Oliveira. "Accuracy of remotely sensing classification of agricultural crops : a comparative study." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367818.
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Jimmerson, Jason William. "Marketing minor crops the determinants of contracting decisions /." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/jimmerson/JimmersonJ0506.pdf.
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Valchovska, Stela. "Entrepreneurship among post-socialist agricultural producers : the case of Bulgaria." Thesis, University of Gloucestershire, 2010. http://eprints.glos.ac.uk/2792/.
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This research is concerned with exploring differences in the meaning of entrepreneurial behaviour among owner-managers of agricultural enterprises in Bulgaria. It aims to gain a better understanding of the origin and development of small businesses in a postsocialist context. Entrepreneurial behaviour is understood as the start-up and development of a new business and is examined through the views and experiences of agricultural producers. An exploratory conceptual framework, encompassing the individual owner-manger, the enterprise and the family, is developed to guide the investigation. It facilitated an analysis of the entrepreneurial process and the relationship between agricultural producers and their enterprises, while also taking into account the possible influences of involved family members. Data were drawn from qualitative face-to-face interviews with a diverse sample of 83 agricultural producers in four rural settlements. The respondents represented different demographic characteristics and agricultural sub-sectors. The findings from this exploratory research provide useful insights into the entrepreneurial behaviour of Bulgarian agricultural producers. Different patterns of engagement with the agricultural enterprises emerge. These are explained through startup motivations and growth aspirations and achievement, which in turn are related to differences in the scale of enterprises. Furthermore, patterns of engagement are related to differences in orientation towards self-employment and adoption of the role of owner-manager. Start-up motivations are associated with a complex interaction of different factors. They are also strongly related to the post-socialist context as represented by macro-level changes. The interviewees recognised and reacted differently to these changes. Presence of involved family members could have either a positive or negative influence on the start-up of new additional activities or the enlargement of existing ones. Contextual issues like the post-socialist background, culture and family contributed to a better understanding of the businesses and entrepreneurial behaviour. The results suggest that the entrepreneurial behaviour of post-socialist agricultural producers requires further research in order to gain an indepth understanding of why they undertake their own business.
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Fioreze, Romeu. "The intermittent drying of agricultural crops with particular reference to energy requirements." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.331946.
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Wang, Xuhui. "Impacts of climate change and agricultural managements on major global cereal crops." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066625/document.
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Les terres cultivées représentent un cinquième de la surface émergée de la Terre. Elles fournissent des nutriments à l'homme, modifient le cycle biogéochimique et l'équilibre énergétique de la terre. L’évolution des terres cultivées dans le contexte du changement climatique et avec une intensification des actions anthropiques constitue un enjeu important pour la sécurité alimentaire et les exigences environnementales du développement durable. Le manuscrit de thèse s’inscrit dans cette thématique en exploitant les données de différentes sources et la modélisation numérique. Les données utilisées sont : les statistiques de rendements, les observations agro-météorologiques à long terme, les résultats des sites d’expérimentation avec du réchauffement, les jeux de données globales issus des processus de fusion ou d’assimilation, les données climatiques historiques et de projection future. La modélisation fait appel aux modèles statistiques et aux modèles de processus. Le manuscrit est composé d’une série de travaux de détection et d'attribution. Ils explorent la phénologie, le rendement et leurs réponses aux changements climatiques et aux pratiques de gestion. Ils sont soit sur l'échelle régionale soit sur l’échelle globale, en fonction de la disponibilité des données et de leur pertinence. Le chapitre 2 décrit la construction et l’utilisation d'un modèle statistique avec des données provinciales de rendement au Nord-est de Chine et des données climatiques historiques. Les résultats montrent un effet asymétrique de la température diurne sur le rendement du maïs. Le rendement du maïs augmente de 10.0±7.7% en réponse à une augmentation moyenne de 1oC pendant la saison de croissance quand il s’agit de la température minimale de nuit (Tmin), mais le rendement diminue de 13,4±7,1% quand il s’agit de la température maximale de jour (Tmax). Il y a une grande disparité spatiale pour la réponse à Tmax, ce qui peut s'expliquer partiellement par le fort gradient spatial de la température pendant la saison de croissance (R = -0,67, P <0,01). La réponse du rendement aux précipitations dépend aussi des conditions d'humidité. Malgré la détection d'impacts significatifs du changement climatique sur le rendement, une part importante de ses variations n’est pas expliquée par les variables climatiques, ce qui souligne le besoin urgent de pouvoir attribuer proprement les variations de rendement au changement climatique et aux pratiques de gestion. Le chapitre 3 présente le développement d’un algorithme d'optimisation basé sur la théorie de Bayes pour optimiser les paramètres importants contrôlant la phénologie dans le modèle ORCHIDEE-crop. L’utilisation du modèle optimisé permet de distinguer les effets de la gestion de ceux du changement climatique sur la période de croissance du riz (LGP). Les résultats du modèle optimisé ORCHIDEE-crop suggèrent que le changement climatique affecte la LGP différemment en fonction des types du riz. Le facteur climatique a fait raccourcir la LGP du riz précoce (-2,0±5,0 jour / décennie), allonger la LGP du riz tardif (1,1±5,4 jour / décennie). Il a peu d'effet sur la LGP du riz unique (-0,4±5,4 jour / décennie). Les résultats du modèle ORCHIDEE-crop montrent aussi que les changements intervenus dans la date de transplantation ont provoqué un changement généralisé de la LGP, mais seulement pour les sites de riz précoce. Ceci compense à la hauteur de 65% le raccourcissement de la LGP provoquée par le changement climatique. Le facteur dominant du changement LGP varie suivant les trois types de riz. La gestion est le principal facteur pour les riz précoce et unique. Ce chapitre démontre aussi qu'un modèle optimisé peut avoir une excellente capacité à représenter des variations régionales complexes de LGPCroplands accounts for one-fifth of global land surface, providing calories for human beings and altering the global biogeochemical cycle and land surface energy balance. The response of croplands to climate change and intensifying human managements is of critical importance to food security and sustainability of the environment. The present manuscript of thesis utilizes various types of data sources (yield statistics, long-term agrometeorological observations, field warming experiments, data-driven global datasets, gridded historical climate dataset and projected climate change) and also modelling approaches (statistical model vs. process model). It presents a series of detection and attribution studies exploring how crop phenology and crop yield respond to climate change and some management practices at regional and global scales, according to data availability. In Chapter 2, a statistical model is constructed with prefecture-level yield statistics and historical climate observations over Northeast China. There are asymmetrical impacts of daytime and nighttime temperatures on maize yield. Maize yield increased by 10.0±7.7% in response to a 1 oC increase of daily minimum temperature (Tmin) averaged in the growing season, but decreased by 13.4±7.1% in response to a 1 oC warming of daily maximum temperature (Tmax). There is a large spatial variation in the yield response to Tmax, which can be partly explained by the spatial gradient of growing season mean temperature (R=-0.67, P<0.01). The response of yield to precipitation is also dependent on moisture conditions. In spite of detection of significant impacts of climate change on yield variations, a large portion of the variations is not explained by climatic variables, highlighting the urgent research need to clearly attribute crop yield variations to change in climate and management practices. Chapter 3 presents the development of a Bayes-based optimization algorithm that is used to optimize key parameters controlling phenological development in ORCHIDEE-crop model for discriminating effects of managements from those of climate change on rice growth duration (LGP). The results from the optimized ORCHIDEE-crop model suggest that climate change has an effect on LGP trends, but with dependency on rice types. Climate trends have shortened LGP of early rice (-2.0±5.0 day/decade), lengthened LGP of late rice (1.1±5.4 day/decade) and have little impacts on LGP of single rice (-0.4±5.4 day/decade). ORCHIDEE-crop simulations further show that change in transplanting date caused widespread LGP change only for early rice sites, offsetting 65% of climate-change-induced LGP shortening. The primary drivers of LGP change are thus different among the three types of rice. Management is predominant driver of LGP change for early and single rice. This chapter demonstrated the capability of the optimized crop model to represent complex regional variations of LGP. Future studies should better document observational errors and management practices in order to reduce large uncertainties that exist in attribution of LGP change and to facilitate further data-model integration. In Chapter 4, a harmonized data set of field warming experiments at 48 sites across the globe for the four most-widely-grown crops (wheat, maize, rice and soybean) is combined with an ensemble of gridded global crop models to produce emergent constrained estimates of the responses of crop yield to changes in temperature (ST). The new constraining framework integrates evidences from field warming experiments and global crop modeling shows with >95% probability that warmer temperatures would reduce yields for maize (-7.1±2.8% K-1), rice (-5.6±2.0% K-1) and soybean (-10.6±5.8% K-1). For wheat, ST was less negative and only 89% likely to be negative (-2.9±2.3% K-1). The field-observation based constraints from the results of the warming experiments reduced uncertainties associated with modeled ST by 12-54% for the four crops
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Neagley, John P. O'Brien Robert T. "Market allocation of agricultural water resources in the Salinas River Valley." Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA245767.
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Thesis (M.S. in Management)--Naval Postgraduate School, December 1990.Thesis Advisor(s): Moore, Thomas P. Second Reader: Gates, William R. "December 1990." Description based on title screen as viewed on April 2, 2010. DTIC Identifier(s): Water Supplies, Irrigation Systems, Salinas River Valley (California), Theses, Free Market, Water Conservation, Public Policy, Salt Water, Policies, Farm Crops, Marketing. Author(s) subject terms: Groundwater Allocation, Groundwater Markets, Agricultural Groundwater, Salinas River Valley. Includes bibliographical references (p. 90-94). Also available in print.
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Craft, Kortney E. "Economic Impacts of Drought on Kentucky Corn, Hay, and Soybeans." TopSCHOLAR®, 2011. http://digitalcommons.wku.edu/theses/1066.
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Understanding climatic impacts is important if we are to comprehend the relationship between climate and society. Weather phenomena can have environmental, economical, and social impacts. Drought is the natural hazard that affects people the most. It is also the most complex and least understood. There is no one universally accepted definition for drought which makes its examination difficult. Droughts’ duration is also difficult to determine because it has no clearly defined onset and end. Also, drought varies both geographically and temporally making uniform drought monitoring difficult. Since drought is difficult to monitor and access, drought impacts are often poorly documented. The purpose of this research was to quantify (in dollars) the impacts of drought on Kentucky’s agriculture. Drought has been recorded historically in Kentucky since the late 1800s. According to the Kentucky Climate Center, the most significant drought years occurred in 1930-31, 1940-42, and 1952-55. Analyses of these years are included as well as the most recent significant drought years in 1987-88, 1999- 2000 and 2007. Four of Kentucky’s important commodities, including corn, soybeans, hay, and beef cattle, were examined during the significant drought years. The total state revenue for these commodities was analyzed during severe drought years vs. non-severe drought years. The result of this research identified how much of a deficit severe drought causes on Kentucky revenue for each of these commodities. This research is important to the general public as well as planners and policy makers. Proper documentation of drought impacts will help identify drought vulnerabilities and result in better risk management and mitigation. Key Words: Drought, Agriculture, Impact Assessment
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Keifer, Jarrett Alexander. "Agricultural Classification of Multi-Temporal MODIS Imagery in Northwest Argentina Using Kansas Crop Phenologies." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2102.
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Subtropical deforestation in Latin America is thought to be driven by demand for agricultural land, particularly to grow soybeans. However, existing remote sensing methods that can differentiate crop types to verify this hypothesis require high spatial or spectral resolution data, or extensive ground truth information to develop training sites, none of which are freely available for much of the world. I developed a new method of crop classification based on the phenological signatures of crops extracted from multi-temporal MODIS vegetation indices. I tested and refined this method using the USDA Cropland Data Layer from Kansas, USA as a reference. I then applied the method to classify crop types for a study site in Pellegrini, Santiago Del Estero, Argentina. The results show that this method is unable to effectively separate summer crops in Pellegrini, but can differentiate summer crops and non-summer crops. Unmet assumptions about agricultural practices are primarily responsible for the ineffective summer crop classification, underlining the need for researchers to have a complete understanding of ground conditions when designing a remote sensing analysis.
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Gutierrez, Pionce Elizabeth Gabriela. "Agricultural performance in northern Ghana: a gender decomposition." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32637.
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Master of ScienceDepartment of Agricultural Economics
Vincent R. Amanor-Boadu
Women represent approximately 50 percent of the active labor force in Sub-Saharan Africa. Even though women are involved in a variety of agricultural activities, they have limited access to resources and have restricted decision-making power compared to their male counterparts (FAO, 2011). These limitations and restrictions are likely to have a significant effect on women’s performance levels compared to men. The present research measures the gender-based performance differences, identifies factors that influence the financial performance levels, and factors contributing to generate disparities between male and female smallholders performance in northern Ghana. Data used in this study are from the Agriculture Production Survey (APS) focusing on the 2013-2014 cropping season. The study uses the Oaxaca-Blinder decomposition method to measure and decompose the gender performance gap in two parts: endowment effect and structural effect. Gross margin is used to measure farmer’s financial performance. The endowment effect is attributed to differences in the explanatory variables, and the structural effect is associated with differences in returns of the explanatory variables. Results from the study indicate there is a gender gap between male and female smallholder farmers with male farmers outperforming females by 46 percent. Land area had the largest significant impact on the explained part of the gender gap, followed by tractor service. The endowment effect portion of the decomposition models is accounted for 35 percent of the gender gap, and the remaining 65 percent is associated with the structural effect. The larger structural effect part suggests that developing programs to establish equality among male and female smallholder producers in terms of access to resources will not close the gender gap. Additionally, factors contributing positively overall to gross margin of smallholder farmers were land area, and tractor services and crops produced. Based on the results of this research, policymakers and agribusiness stakeholders may look to reduce the gender gap existing between smallholder farmers in northern Ghana by empowering women by providing them access to land area and tractor services. Further research into factors affecting the gender gap in financial performance in agricultural activities is warranted.
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Bradley, Bo Dylan. "The impacts of farm finances of substituting mechanical for chemical weed control in arable crops." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263299.
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Ng, Wai-yip, and 吳偉業. "Impact of climatic change during little ice age on agricultural development in north China, 1600-1650." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43209397.
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Smith, Joshua Dwayne. "Impacts of Cover Crops on Carbon Dioxide and Nitrous Oxide Flux from a Row Crop Agricultural Field in Central Illinois." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1391.
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In the United States, there is renewed interest in incorporating cover crops into agricultural systems to provide a variety of potential benefits related to soil quality, water quality, and greenhouse gas emissions. This study focused on assessing whether cover crops influence N2O and CO2 emissions in a central Illinois agricultural research field over two years (2011-2013) of cover crop growing seasons. Three winter cover crop systems, annual ryegrass (Lolium multiflorum), cereal rye (Secale cereale), and a cereal rye (2011)/ hairy vetch (Vicia villosa) (2012) rotation were planted after fall 2011 and 2012 harvests. The field included a total of eight main plots, two of each treatment, and two no cover crop control plots. Soil carbon dioxide (CO2) and nitrous oxide (N2O) fluxes were measured from the plots in a single corn (Zea mays) - soybean (Glycine max) system for two cover crop growing seasons. Fluxes of CO2 and CO2 were measured in March 2012, August 2012, and February 2013. The CO2 flux measurements were performed by using an infrared gas analyzer. The N2O fluxes were analyzed from samples collected at 0, 10, 20, 30 min intervals from the same closed dynamic chamber system. Both CO2 and N2O fluxes were computed from respective gas concentrations over time. Data were analyzed with a repeated measures mixed model procedure. N2O fluxes from the cereal rye/hairy vetch plots were greater than the no cover control and annual ryegrass plots, suggesting that cover crops may not decrease N2O fluxes immediately after being incorporated into a cropping system. In contrast, CO2 fluxes did not significantly differ among the treatments, but the cereal rye/hairy vetch plot sequestered ~100 kg C ha-1 of soil organic carbon (SOC). Overall, it was observed that some cover crop plots can have higher N2O fluxes than plots without cover crops, but cover crops have the long-term potential to sequester C in croplands demonstrating that their use should still be considered a sustainable agriculture practice.
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Alam, Shamsul. "The effects of price and non-price factors on the production of major crops in Bangladesh." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315583.
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Sheldon, Bonita Joy. "Heavy metal uptake and accumulation in agricultural crops in urban areas of the Western Cape." Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/2006.
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Thesis (MTech (Physical Sciences))--Cape Peninsula University of Technology, 2005.A research study into heavy metals in the Cape Town area, found significant amounts of potentially toxic metals such as lead, cadmium, chromium and iron leaching into the underground aquifer. A further additional study conducted on a community garden in Khayelitsha, showed that vegetable crops have the tendency to accumulate certain heavy metals if they are present in soil and water resources. This study was centered around the Philippi Horticultural Area, which is a large significant farming area within the Cape Metropolitan Region. The significance of the study lies in the fact that at least 50% of the local farmers' produce is sold directly to street traders, residents, local supermarket-chains and restaurants. The remainder of the produce is sold at the Epping Market. The purpose of this study was to investigate heavy metal accumulation in various vegetable crop species taken from some of the local farms in the Phillipi Farming area with the objective to: • investigate heavy metal accumulation in various vegetable crop species taken from some local farms in the Phillipi Farming area. • determine the concentrations of heavy metals present in water and soil resource since these will be the primary source of heavy metals to the vegetables. • determine the soil pH and soil organic matter as these two factors would determine the bie-availability ofthe heavy metals. • identify those crops that pose a definite health risk by means of comparing the determined results to the allowed limits.
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Wong, Wai Yoke V. "The role of scientific research in the development of exported cash crops with particular reference to Malaysia." Thesis, Manchester Metropolitan University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354359.
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Crane, Andrew John. "The spectral detection of salt stress in cotton." Thesis, University of Portsmouth, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292358.
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Kyllmar, Katarina. "Nitrogen leaching in small agricultural catchments : modelling and monitoring for assessing state, trends and effects of counter-measures /." Uppsala : Dept. of Soil Sciences, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a485.pdf.
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Wickson, Fern. "From risk to uncertainy Australia's environmental regulation of genetically modified crops /." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060727.135007/index.html.
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Jones, Kevin Edison. "The politics of new agricultural technologies : contesting risk, science and governance." Thesis, Brunel University, 2004. http://bura.brunel.ac.uk/handle/2438/7890.
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This thesis provides a sociological exploration of the politics of new agricultural technologies in the United Kingdom. It addresses some of the key issues involved in these politics, as well as how they are discussed and fought over. Conceptually it addresses these questions by focussing on issues of risk, science and governance. In doing so, this thesis situates the politics of GM crops and foods in relation to wider normative concerns about the cultural values, relationships and institutions shaping agriculture, and British society more generally. Empirically, this thesis applies a qualitative methodology, primarily relying on data generated from a series of in-depth interviews. Through these interviews active participants in the debate were able to express a variety of opinions about the risks and benefits of agricultural biotechnology. The interview data is further supplemented by some documentary evidence, particularly as relates to several government led initiatives addressing agricultural debates in terms of contestations over risk and knowledge. Key chapters in this thesis look at the way in which the debate over GM crops and foods has been shaped by perceptions of the role and values of the life-industry, science and the Government in developing and regulating biotechnology. Finally, this thesis also addresses how society, and practices of governance in particular, are able to accommodate these political issues in managing risk and regulating technological change.
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Burgoa, Chopitea Marco Antonio Domingo. "Analysis and organization of the family based agricultural production system in the Poroma community of Oropeza province." BYU ScholarsArchive, 2000. https://scholarsarchive.byu.edu/etd/5335.
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This research analyzed the management strategies and organization of crop production in a family agricultural system. This study took place in the Poroma community, Oropeza province, Chuquisaca Department, in Bolivia, at the so called “red zone”, so named for its extreme poverty. The agricultural system used in this study is unique to the pre-puna area of Bolivia and is located in a meso-thermal valley with wet summers. This agricultural system uses a diverse number of native and cultivated plants and animals and incorporates interrelated production strategies in agriculture, animal husbandry, forestry, and crafts. Two important production sectors have been identified in the community: sunny and shady. The four main crops in these sectors are potato, corn, wheat, and barley, with an additional 35 complementary crops. Additionally, 78 crops were identified with specific agronomic and nutritious characteristics. These crops included two used for candy; 56 for human health, and 36 for firewood, wood, dye, and tanning procedures. Limitations with this agricultural system are weak community structural organization, the presence of pests and diseases in crops, and the lack of traditional cultivation practices.
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Hayman, Peter Theodore, of Western Sydney Hawkesbury University, of Science Technology and Environment College, and School of Environment and Agriculture. "Dancing in the rain : farmers and agricultural scientists in a variable climate." THESIS_CSTE_EAG_Hayman_P.xml, 2001. http://handle.uws.edu.au:8081/1959.7/138.
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This study describes how farmers manage climate variability in dryland crop production, and aims to contribute to the theory and practice of decision support for managing climate variability. The intent was to study farmer decision making to see how DSS could be used to deliver information and procedures on climate risk to farmers more effectively. The study investigated whether there are significant differences between farmers' subjective distributions of seasonal rainfall and its derivatives (such as crop yield and fallow recharge) and a probability distribution derived from long-term records and simulation models, and whether these differences in risk assessment lead to changes in the optimum decision. Subjective probability distributions of rainfall and its derivatives were collected from farmers and advisers and it was found the overall match between these and long term records and simulation models was close. This study found little evidence to support the role of DSS for routine decision making, but this does not lessen the value of distributions derived from simulation models. Rather, it provides an opportunity for both farmers and scientists to learn.Doctor of Philosophy (PhD)
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Msuya, Kassim Jumanne. "Applicability of drip irrigation for smallholder farmers: A case study of the horticultural industry in Tanzania." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469152691.
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Kiger, Sarah E. "Environmental and Energy Benefits from Conservation Reserve Program Lands versus Returns from Row Crops." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244043054.
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Doerr, Zacharie. "Evaluating the ability to detect foreign objects in crops using laser range scanners mounted on agricultural vehicles." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28521.
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The general objective of this work was to evaluate the effectiveness of a Laser Measurement Systems (LMS) mounted on an agricultural vehicle at detecting foreign objects in standing crops such as Hay, Wheat, Soy, and Oats. More specifically, to evaluate the effectiveness of various algorithms and evaluating the affect of various test parameters. A SICK LMS 291-S14 scanner was placed on an agricultural tractor to scan different standing crops in which standard test objects were placed.
A high rate of detection was found for objects that were significantly taller than crops. Crop density or foliage cover had a negative impact on the detection rate for shorter test objects. Increasing vehicle speed was also found to reduce detection rates due to lower field scan resolution. The average height and density methods had greater success rates of 72.4% and 49.4%. The discontinuity and connectivity methods had a success rate of 20.6% and 18% respectively.
This system, with the conjunction of other safety systems, may be useful for ensuring safe field operation of autonomous agricultural vehicles.
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Gerhards, Max [Verfasser], and Thomas [Akademischer Betreuer] Udelhoven. "Advanced Thermal Remote Sensing for Water Stress Detection of Agricultural Crops / Max Gerhards ; Betreuer: Thomas Udelhoven." Trier : Universität Trier, 2018. http://d-nb.info/1197807756/34.
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Čepulienė, Rita. "Dynamics of accumulation of allelochemical compounds in oilseed rape and effect on agricultural crops and weeds." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20141230_175312-56329.
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Research objective. The study was aimed to identify the dynamics of accumulation of phenolic compounds and glucosinolates in oilseed rape and the effect of different morphological parts of oilseed rape on agricultural plants and weeds. The goals of the studies. The following goals were set in order to reach the aim of the studies: 1. To identify the dynamics of accumulation of phenolic compounds in oilseed rapeduring vegetation. 2. To analyse composition of allelochemical compounds of different morphological parts of rape residues after harvesting and ascertain quantitative and qualitative changes of these compounds in rape residues that decomposed in the soil for a different period. 3. To ascertain the effect of different morphological parts of oilseed rape that remain immediately after harvesting on the germination, shoot height and root length of agricultural plants and weeds. 4. To ascertain the effect of different morphological parts of oilseed rape that decomposed in the soil for a different period on the germination, growth of shoots and roots of agricultural plants and weeds.Tyrimų tikslas. Nustatyti fenolinių junginių ir gliukozinolatų kaupimosi rapsuose dinamiką bei rapsų skirtingų morfologinių dalių liekanų poveikį žemės ūkio augalams ir piktžolėms. Tyrimų uždaviniai: 1. Nustatyti fenolinių junginių kaupimosi dinamiką rapsuose vegetacijos metu. 2. Ištirti alelocheminių junginių sudėtį rapsų skirtingų morfologinių dalių liekanose po derliaus nuėmimo ir nustatyti jų kiekybinius ir kokybinius pokyčius skirtingą laiką dirvoje irusiose rapsų liekanose. 3. Nustatyti rapsų atskirų morfologinių dalių, liekančių iškart po derliaus nuėmimo, poveikį žemes ūkio augalų ir piktžolių sėklų dygimui, daigų aukščiui ir šaknų ilgiui. 4. Nustatyti skirtingą laiką dirvoje irusių rapsų morfologinių dalių poveikį žemės ūkio augalų ir piktžolių sėklų dygimui, daigų bei šaknų augimui.
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Van, Velden Julia. "Cranes and crops: investigating the viability of blue cranes in agricultural lands of the Western Cape." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20780.
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The Western Cape population of Blue Cranes (Anthropoides paradiseus) is of great importance as the largest and most stable population throughout its range. This species is strongly associated with agricultural lands in the Western Cape, and therefore may come into conflict with farmers who perceive them as damaging to crops. Blue Cranes are suspected to be locally nomadic, but little information has been collated to support this and they are also relatively understudied in terms of demographic parameters. This project investigates the viability of the Blue Crane population in three ways: exploring farmer attitudes towards cranes in two regions of the Western Cape (Swartland and Overberg) using 40 semi-structured interviews, generating estimates of survival using Mark-Recapture methods and exploring movement patterns using a long-term data set of resightings of marked individuals. These three components all add important aspects to the overarch ing goal of achieving a better understanding of threats to Blue Cranes in the Western Cape, and thus the population's long-term viability. Perceptions of cranes differed widely between regions: farmers in the Swartland perceived cranes to be particularly damaging to the feed crop sweet lupin (65% of farmers reported some level of damage by cranes), and 40% of these farmers perceived cranes as more problematic than other common bird pests. Farmers in the Overberg did not perceive cranes as highly damaging, although there was concern about cranes eating feed at sheep troughs. Survival was age-structured: individuals in their first year had a survival of 0.6, those in their second and third years that of 0.87 and adult individuals (4+) that of 0.72. The adult survival estimate is suspected to be underestimated due to ring loss. Resightings of colour-ringed cranes suggest that movements in the Western Cape were localized, with an average displacement of 24.6 km from their natal point. Only 3.8% of marked individuals were resighted in both the Overberg and the Swartland regions, indicating that movement between these regions was low and regional fidelity was high. There was significant movement within the Overberg however, and 90% of movements of >10 km were made within this region. This species therefore appears to be resident to locally nomadic in nature. Evidence for natal philopatry was also found: 57% of adults returned at least once to the area where they were ringed as juveniles. These results highlight the need for location-specific management solutions to crop-damage by cranes, and contribute to the understanding of basic demographics for this vulnerable species.
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Bell, Lindsay William. "Prospects of Dorycnium species to increase water use in agricultural systems of southern Australia /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0033.
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Hunt, Gillian A. "Environmental modification of the responses of vicia faba to sulphur dioxide." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/12479.
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Ren, Xiaomeng, and University of Lethbridge Faculty of Arts and Science. "Agricultural vulnerability to drought in southern Alberta : a quantitative assessment." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2007, 2007. http://hdl.handle.net/10133/398.
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Agricultural vulnerability is generally referred to as the degree to which agricultural systems are likely to experience harm due to a stress. In this study, an existing analytical method to quantify vulnerability was adopted to assess the magnitude as well as the spatial pattern of agricultural vulnerability to varying drought conditions in Southern Alberta. Based on the farm reported data and remote sensing imagery, two empirical approaches were developed to implement vulnerability assessment in Southern Alberta at the quarter-section and 30 meter by 30 meter pixel levels. Cereal crop yield and the Standardized Precipitation Index (SPI) were specified as the agricultural wellbeing and stress pair in the study. Remote sensing data were used to generate cereal crop yield estimations, which were then implemented in vulnerability quantification. The utility of the remote sensing data source for vulnerability assessment were proved. The spatial pattern of agricultural vulnerability to different severity and duration of drought were mapped.xii, 127 leaves : ill. ; 29 cm.
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Sabundjian, Michelle Traete. "Efeito residual do consórcio de milho e Urochloa ruziziensis com inoculação de Azospirillum brasilense e adubação nitrogenada em cobertura no cultivo do feijão e trigo irrigado em sistema plantio direto /." Ilha Solteira, 2013. http://hdl.handle.net/11449/98737.
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Orientador: Orivaldo ArfBanca: Ricardo Antonio Ferreira Rodrigues
Banca: Neli Cristina Belmiro dos Santos
Resumo: A expansão do sistema plantio direto pelo país está cada vez mais diversificando as formas como os sistemas de produção são implantados e manejados. Diante deste novo cenário agrícola, o presente trabalho avaliou a influência de culturas antecessoras como milho, Urochloa ruziziensis e o consórcio entre elas na presença e ausência da inoculação de sementes com Azospirillum brasilense e o fornecimento de nitrogênio em cobertura no desenvolvimento, componentes de produção e produtividade de grãos do feijoeiro e do trigo. O trabalho foi desenvolvido no município de Selvíria, Mato Grosso do Sul, Brasil, na safra 2011/12. O delineamento experimental para o milho e Urochloa foi o de blocos ao acaso com 4 repetições e 8 tipos de combinações assim constituídas: (milho; milho - Azospirillum brasilense; Urochloa ruziziensis cv. Comum; Urochloa ruziziensis cv. Comum - Azospirillum brasilense; milho + U. ruziziensis cv. Comum; milho - A. brasilense + U. ruziziensis cv. Comum; milho + U. ruziziensis cv. Comum - A. brasilense; milho - A. brasilense + U. ruziziensis cv. Comum - A. brasilense ). O delineamento experimental para o feijão e trigo foi o de blocos ao acaso em esquema fatorial 8x4 com os tratamentos constituídos pelas 8 coberturas vegetais e combinação de 4 doses de nitrogênio em cobertura (0, 30, 60 e 90 kg ha- 1 de N), com 4 repetições. Durante a condução do experimento foram realizadas as seguintes avaliações: cobertura vegetal (quantidade) do milho e Urochloa, além de características agronômicas, componentes de produção e produtividade das culturas do feijão e trigo. Pelos resultados obtidos concluiu-se que o feijoeiro e o trigo apresentam boa produtividade quando cultivados em sucessão ao milho consorciado com Urochloa ruziziensis ambos inoculados, considerando a produtividade das culturas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The expansion of the no-tillage system is increasingly diversified the way the production systems are deployed and managed in Brazil. Given this new agricultural scenario, the objective of this work was to evaluate the effect of sidedressing nitrogen on bean and wheat grown under no-tillage, in succession to mayze, Urochloa ruziziensis or mayze intercropped with Urochloa ruziziensis, in the presence and absence of inoculation of seeds with Azospirillum brasilense, in the development of production and productivity components of the bean grains and wheat irrigated in no-tillage system. This work was developed in the city of Selvíria, Mato Grosso do Sul, Brazil, in harvest 2011/12. The experiment design for mayze and Urochloa was a randomized block with 4 replications and 8 treatments like this: (mayze; mayze - Azospirillum brasilense; Urochloa ruziziensis cv. Comum; Urochloa ruziziensis - Azospirillum brasilense; mayze + U. ruziziensis; mayze - A. brasilense + U. ruziziensis; mayze + U. ruziziensis- A. brasilense; mayze - A. brasilense + U. ruziziensis - A. brasilense). The experiment design for bean and wheat was a randomized block in a factorial scheme 8x4 with 32 treatments, use of cover crops and 4 levels of nitrogen fertilization at sidedressing (0, 30, 60, 90 kg ha-1) and 4 replications. During the experiment the following evaluations were performed: Vegetation cover (amount) of mayze and Urochloa, and agronomic characteristics, yield components and crop yields of wheat and beans. The grain yield was higher in treatments where, in previous crop, when grown after mayze inoculated + Urochloa ruziziensis inoculated, considering bean and wheat productivity, the ability to produce mayze and at the same time increasing the production of straw benefiting no-tillage system, the application of nitrogen sidedressing did not affect the yield... (Complete abstract click electronic access below)
Mestre
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Ismayilova, Rubaba Mammad. "An analysis of producing ethanol and electric power from woody residues and agricultural crops in East Texas." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5773.
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The increasing U.S. dependence on imported oil; the contribution of fossil fuels to the
greenhouse gas emissions and the climate change issue; the current level of energy
prices and other environmental concerns have increased world interest in renewable
energy sources. Biomass is a large, diverse, readily exploitable resource. This
dissertation examines the biomass potential in Eastern Texas by examining a 44 county
region. This examination considers the potential establishment of a 100-megawatt (MW)
power plant and a 20 million gallon per year (MMGY) ethanol plant using
lignocellulosic biomass. The biomass sources considered are switchgrass, sugarcane
bagasse, and logging residues. In the case of electricity generation, co-firing scenarios
are also investigated. The research analyzes the key indicators involved with economic
costs and benefits, environmental and social impacts. The bioenergy production
possibilities considered here were biofeedstock supported electric power and cellulosic
ethanol production. The results were integrated into a comprehensive set of information
that addresses the effects of biomass energy development in the region. The analysis indicates that none of the counties in East Texas have sufficient
biomass to individually sustain either a 100% biomass fired power plant or the cellulosic
ethanol plant. Such plants would only be feasible at the regional level. Co-firing
biomass with coal, however, does provide a most attractive alternative for the study
region. The results indicate further that basing the decision solely on economics of
feedstock availability and costs would suggest that bioenergy, as a renewable energy, is
not a viable energy alternative. Accounting for some environmental and social benefits
accruing to the region from bioenergy production together with the feedstock economics,
however, suggests that government subsidies, up to the amount of accruing benefits,
could make the bioenergies an attractive business opportunity for local farmers and
investors.
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Wu, Aisheng. "Testing and development of the Canadian Land Surface Scheme (CLASS) for forests, agricultural crops and bare soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0018/NQ46452.pdf.
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Crosier, Joshua D. "Agricultural Utilization of Brewers’ Spent Grains & Sawdust: Effects on Fertility of Soils and Productivity of Crops." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1417788956.
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Ng, Wai-yip. "Impact of climatic change during little ice age on agricultural development in north China, 1600-1650 Xiao bing qi qi hou bian qian yu Hua bei nong ye fa zhan : 1600-1650 nian jian de guan cha /." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43209397.
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Shelton, Rebecca Erin. "CONSERVATION AGRICULTURE IN KENTUCKY: INVESTIGATING NITROGEN LOSS AND DYNAMICS IN CORN SYSTEMS FOLLOWING WHEAT AND HAIRY VETCH COVER CROPS." UKnowledge, 2015. http://uknowledge.uky.edu/pss_etds/59.
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Unintentional nitrogen (N) loss from agroecosystems produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, adoption of conservation agricultural management practices, such as no-till and cover cropping, has increased. This study assessed N loss via leaching, NH3 volatilization, N2O emissions, and N retention in plant and soil pools of corn conservation agroecosystems across a year. Three systems were evaluated: 1) an unfertilized organic system with cover crops Vicia villosa, Triticum aestivum, or a mix of the two; 2) an organic system with a Vicia cover crop employing three fertilization schemes (0 N, organic N, or a cover crop N-credit approach); 3) a conventional system with a Triticum cover crop and three fertilization techniques (0 N, urea N, or organic N). During cover crop growth, species affected N leaching but gaseous emissions were low across all treatments. During corn growth, cover crop and fertilizer approach affected N loss. Fertilized treatments had greater N loss than unfertilized treatments, and fertilizer type affected gaseous fluxes temporally and in magnitude. Overall, increased N availability did not always indicate greater N loss or yield, suggesting that N conserving management techniques can be employed in conservation agriculture systems without sacrificing yield.
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Wu, Ziping. "An economic analysis of supply response for the main grain crops in China, with particular emphasis on the impact of reforms since 1979." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387924.
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El-Kholei, Ahmed Mohammed Salah. "Evaluating the impact of economic agricultural policies during the reform era for major crops and crop rotations in Egypt : a policy analysis matrix approach." Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/13346/.
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In 1986, Egypt implemented a succession of comprehensive economic reforms both in the agriculture sector and more generally such as the Economic Reform and Structural Adjustment Program (ERSAP) of 1991. Since then, the agricultural sector has been gradually transformed from one characterised by central planning and governmental controls to one that is more free market oriented. This study employs the Policy Analysis Matrix technique to evaluate the impacts of reform policies on eleven major crops (wheat, maize, sugar cane, soy bean, broad bean, cotton, rice, tomatoes, potatoes, long and short berseem) and their associated crop rotations (crop mix) during the period 1986-2000. The PAM offers six tools of economic indicators. The first (private Cost Ratio) is used to identify the competitiveness of crops domestically. The second (Domestic Resource Cost) is employed in an attempt to identify those commodities in which Egypt has a comparative advantage/disadvantage. The third (Nominal Protection Coefficient for inputs and outputs) is used to measure the divergences between the domestic and international prices for inputs and output. The fourth (Effective Protection Coefficient) reflects the complete pattern of incentives to farmers in the tradable commodities markets, combining the separate influences of polices represented by the NPCO and NPCI measures. The fifth and sixth (profitability Coefficient and Subsidy Ratio to Producers) estimates the net protection effects afforded to each of the major sectors by the whole range of policy intervention. The most important findings are that: (1) The Egyptian pricing policy in the reform era is still encouraging domestic production of importable products (by setting their prices above world prices) while export products are taxed relative to their equivalent world prices. (2) Cotton, the main historical export commodity, is shown to be grown with a comparative disadvantage since it receives the highest levels of subsidy. (3) On the other hand, wheat showed a remarkably positive example for the high response from farmers to the reformed pricing policies with an increase in its area and its productivity by 83% and 60% respectively. (4) There is a high response of change in planted area to water charges. The conclusion of these analyses is that the impact of policy changes has indeed been positive, especially in relation to areas of crop production. But many remains to be done, for example, growers' still face problems in marketing, accessing to inputs, processing and trade.
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Cerqueira, Francisco Diogo de Almeida. "Influence of agricultural practices on the microbiome and the antibiotic resistance gene complement in soils, plants, and crops." Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/669200.
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Antibiotic (AB) Resistance is an increasing global problem for public health, with multi-resistant bacteria persisting and spreading not only in clinical settings but also in the environment. One of the possible vectors of this spread is the use and re-use of waste water (WW) and of manure and sludge from WW treatment plants (WWTPs) in different agriculture practices (irrigation, soil amendment). These practices are becoming widespread in regions with scarcity of water. WWTPs are known as AB resistance hotspots, whereas soil amendment by organic fertilization is known to increase AB resistance in the soil microbiomes. Hence, there is a growing concern about the possible transmission of AB resistance from agricultural soils to crops and, ultimately, to the microbiomes of consumers' guts. In this Thesis, this issue was assessed in commercial fields producing vegetable crops. This strategy allowed us to analyze AB resistance elements in foodstuffs actually reaching the consumers, and to understand the risk their consumption poses. Moreover, this Thesis tackles the alterations in soil, plant and crops bacterial communities due to these agricultural practices. To achieve this, five agricultural fields located in the area of Barcelona (NE Spain) were selected, under different irrigation regimes and soil amendment. The selected crops were lettuce, tomatoes, and broad beans as they represent vegetables with different edible parts, commonly eaten either raw or beans, as cooked. The Thesis is divided into five chapters. Chapter I describes the state of the art of the studies of ABR in food and agricultural fields and presents the objectives of the PhD project. Chapter II and III assess the distribution of ARGs and microbiomes along the soil-plant continuum in Lycopersicum esculentum and, grown in peri-urban and rural agricultural fields under different irrigation regimes and soil amendment. Our data show that field practices influenced the distribution of ARGs and intI1 along the soil-plant continuum in both cases, although the impact on soil and plant microbiomes differed between the two crops. In tomatoes, few abundant bacterial families discriminated the different agricultural fields, including Pseudomonadaceae and Enterobacteriaceae. The predominance of Pseudomonadacea correlated positively with the levels of intI1, blaTEM, blaOXA-58 and sul1 detected in the fruits. In contrast, microbiomes from broad bean plant parts (beans, leaves, roots) were dominated by Rhizobiales, whose predominance inversely correlated with intl1 and ARGs abundances. We concluded that Rhizobiales limits the translocation of ARGs into the crops, as well as the colonization of roots and plant parts by other bacteria. Chapter IV integrates the data from the distribution and abundance of the ARGs in different model crops. The results obtained from the different soils and crops showed that ARGs were detected in all plant compartments, with highest loads in roots and lowest in fruits or beans. ARGs profiles within the crops reflect the soil ARG composition. The analyses also showed positive correlations between certain soil taxa and ARG profiles. The crop type revealed to be determinant for both ARG distribution and microbiome composition. Irrigation water appeared to have a limited influence, suggesting that the soil amendment practices were determinants on ARG distribution and on their abundance in edible crop parts. Chapter V presents a general discussion of the results showed previously, followed in Chapter VI including the main conclusions of the Thesis.La resistencia a los antibióticos (AB) es un problema mundial cada vez mayor para la salud pública, con bacterias multirresistentes que persisten y se propagan no solo en entornos clínicos sino también en el medio ambiente. Uno de los posibles vectores de esta propagación es el uso y la reutilización de aguas residuales (WW) y de estiércol y lodos de plantas de tratamiento de WW (WWTP) en diferentes prácticas agrícolas (riego, enmienda del suelo). Estas prácticas se están generalizando en regiones con escasez de agua. Las WWTP se conocen como puntos calientes de resistencia AB, mientras que la enmienda del suelo por fertilización orgánica aumenta la resistencia AB en los microbiomas del suelo. Existe una creciente preocupación por la posible transmisión de la resistencia AB de los suelos agrícolas a los cultivos y, en última instancia, a los microbiomas de los intestinos de los consumidores. En esta Tesis, este tema se evaluó en campos comerciales que producen cultivos de hortalizas. Esta estrategia nos permitió analizar los elementos de resistencia AB en los alimentos que realmente llegan a los consumidores, y comprender el riesgo que representa su consumo. Además, esta Tesis aborda las alteraciones en las comunidades bacterianas del suelo, plantas y cultivos debido a estas prácticas agrícolas. Para lograr esto, se seleccionaron cinco campos agrícolas ubicados en el área de Barcelona (NE España), bajo diferentes regímenes de riego y enmienda del suelo. Los cultivos seleccionados fueron lechuga, tomate y habas, ya que representan vegetales con diferentes partes comestibles, que comúnmente se comen crudos o frijoles, como cocidos. La tesis se divide en cinco capítulos. El Capítulo I describe el estado del arte de los estudios de ABR en campos agrícolas y alimentarios y presenta los objetivos del proyecto de doctorado. Los capítulos II y III evalúan la distribución de ARG y microbiomas a lo largo del continuo suelo-planta en Lycopersicum esculentum y, cultivados en campos agrícolas periurbanos y rurales bajo diferentes regímenes de riego y enmienda del suelo. Nuestros datos muestran que las prácticas de campo influyeron en la distribución de ARG e intI1 a lo largo del continuo suelo-planta en ambos casos, aunque el impacto en el suelo y los microbiomas de las plantas difirió entre los dos cultivos. En los tomates, pocas familias bacterianas abundantes discriminaron los diferentes campos agrícolas, incluidas Pseudomonadaceae y Enterobacteriaceae. El predominio de Pseudomonadacea se correlacionó positivamente con los niveles de intI1, blaTEM, blaOXA-58 y sul1 detectados en las frutas. En contraste, los microbiomas de las partes de la planta de frijol ancho (frijoles, hojas, raíces) estuvieron dominados por Rhizobiales, cuyo predominio se correlacionó inversamente con las abundancias intl1 y ARG. Llegamos a la conclusión de que Rhizobiales limita la translocación de ARG en los cultivos, así como la colonización de raíces y partes de plantas por otras bacterias. El Capítulo IV integra los datos de la distribución y abundancia de los ARG en diferentes cultivos modelo. Los resultados obtenidos de los diferentes suelos y cultivos mostraron que se detectaron ARG en todos los compartimentos de las plantas, con cargas más altas en las raíces y más bajas en frutas o frijoles. Los perfiles de ARG dentro de los cultivos reflejan la composición de ARG del suelo. Las análisis también mostraron correlaciones positivas entre ciertos taxones del suelo y perfiles ARG. El tipo de cultivo reveló ser determinante tanto para la distribución de ARG como para la composición del microbioma. El agua de riego parecía tener una influencia limitada, lo que sugiere que las prácticas de enmienda del suelo fueron determinantes en la distribución de ARG y en su abundancia en las partes comestible. El Capítulo V presenta una discusión general de los resultados mostrados anteriormente, y el Capítulo V