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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Economics of nitrogen fertilization: Site-specific application, risk implications, and greenhouse gas emissions

Karatay, Yusuf Nadi 18 February 2020 (has links)
In Anbetracht des Kompromisses zwischen der Erzielung des höchsten Gewinns und der geringsten Umweltbelastung ist ein tiefes Verständnis der ökonomischen Folgen der Stickstoff (N) Düngung erforderlich. Die vorliegende Doktorarbeit liefert umfassende Einblicke in (i) die Auswirkungen des standortspezifischen N-Managements (SSNM) auf die Rentabilität und Risikominderung, (ii) die Auswirkungen von Unsicherheiten und Risikoeinflüssen auf optimale N-Düngergaben und (iii) das Potenzial und die Kosten der Vermeidung von Treibhausgas (THG) Emissionen durch N-Düngereduktion. Ein Modellierungsansatz wurde entwickelt, um die Wirkung von Ertrag und Proteingehalt, Wirtschafts- und Risikoauswirkungen sowie THG-Emissionen auf die N-Düngung zu simulieren. Die Ergebnisse der Arbeit zeigen, dass SSNM die Wirtschaftlichkeit verbessert, indem es eine höhere Weizenqualität und damit Preisprämien erzielt. SSNM reduziert das Risiko, die Backqualität nicht zu erreichen, und es gibt keine wesentlichen Nachteile beim Verlustrisikomanagement im Vergleich zum einheitlichen Management. Preisprämien für eine höhere Weizenqualität bieten Anreize für höhere N-Düngergaben. Prämien verflachen die Gewinnfunktion weiter, was unzureichende Argumente für eine Absenkung des N-Inputs aus der Wirtschaftlichkeitssicht liefert, selbst bei einer hohen Risikoaversion der Landwirte. Eine moderate Reduzierung der mineralischen N-Düngung kann die THG-Emissionen bei moderaten Opportunitätskosten mindern. Die THG-Vermeidung durch N-Düngereduktion in einer bestimmten Region kann unter Berücksichtigung kultur- und ertragszonenspezifischer Ertragswirkungen optimiert werden. Insgesamt liefert diese Arbeit wichtige Erkenntnisse über die Chancen und Nachteile der Anpassung der N-Düngergaben. Darüber hinaus leistet sie einen direkten Beitrag zur Identifizierung von kosten- und risikoeffizienten N-Managementoptionen und bildet die Grundlage für effektive politische Ansätze zur THG-Vermeidung durch selektive N-Düngereduktion. / Considering the tradeoff between achieving the highest profit and causing the lowest environmental impact, there is a need for a profound understanding of the economic consequences of nitrogen (N) fertilizer application. The present doctoral research provides comprehensive insights into (i) effects of site-specific N management (SSNM) on profitability and risk mitigation; (ii) impacts of uncertainties and risk implications on optimal N fertilizer rates; and (iii) potential and costs of mitigating greenhouse gas (GHG) emissions by N fertilizer reduction. A modelling approach was developed to simulate the response of yield, protein, economic and risk implications, and GHG emissions to N fertilizer application. Findings of the thesis show that SSNM improves profitability by achieving higher grain quality, thus, price premiums. SSNM reduces the risk of not reaching the baking grain quality and poses no considerable disadvantage on downside risk management compared to uniform management. Price premiums for higher wheat quality provide incentives for higher N input rates. Premiums further flatten the profit function, giving insufficient arguments for lowering N input from a farm profitability perspective, even in presence of high risk aversion of farmers. Moderate reduction of mineral N fertilizer can mitigate GHG emissions at moderate opportunity costs. GHG mitigation by N fertilizer reduction in a given region can be optimized considering crop and yield-zone-specific yield responses. Overall, this thesis provides important insights on chances and drawbacks of adjusting N fertilizer rates. Moreover, it makes a direct contribution in identifying cost- and risk-efficient N management options and provides a basis for effective policy approaches to reduce GHG emissions by selective N fertilizer reduction.
72

An analysis of precision agriculture in the South African summer grain producing areas / Hendriks J.

Hendriks, Joseph January 2011 (has links)
Both globally and locally, agriculture faces ever increasing challenges such as high input costs, strict environmental laws, decrease in land for cultivation and an increase in demand due to the growing global population. Profitability and sustainability requires more effective production systems. Precision agriculture is identified as such a system and is built upon a system approach that aims to restructure the total system of agriculture towards low input, high efficiency and sustainable agriculture. The aim of this study was to analyse the state of precision agriculture in the summer grain producing areas of South Africa, specifically the North West and Free State provinces. In order to achieve this, a literature study was conducted. During the literature study the term ‘precision agriculture’ was defined and discussed. The precision agriculture cycle and its components were explained and benefits of precision agriculture were identified. The literature study was concluded with identifying and discussing the most widely used and most beneficial technologies as well as reasons for slow adoption. Findings from the literature study were used to investigate the state of precision agriculture locally. In order to achieve this, a quantitative approach was used and information was collected by means of an empirical study using a questionnaire. Questionnaires were distributed to farmers using selling agents of an agricultural company that is well represented in the targeted areas. The data was then statistically analysed. The survey showed that only 52% of summer grain producing farmers in the North West and Free State provinces of South Africa practises precision agriculture as defined in the v literature study. The study also revealed that the majority of precision agriculture farmers are over the age of 40, have more than 16 years of farming experience, are well educated, cultivate more than 1,000 hectares and uses none or little irrigation. The most commonly used precision agriculture technologies were grid soil sampling and yield monitors. The perception among most of the farmers was that precision technologies are not very affordable, not easily available and that it lacks proper testing with regards to efficiency. The group of summer grain–producing farmers that have correctly implemented precision agriculture as per definition stated that the benefits they derived from precision technologies include reduction in input costs, increased outputs and improved management skills. Too high implementation costs and technologies not providing enough benefits were among the main reasons farmers do not implement precision agriculture. It was concluded that a significant effort and amount of work is needed to increase the use of precision agriculture among summer grain–producing farmers in the targeted areas. A consolidated effort from government, agricultural institutions and agricultural companies will be needed to achieve this goal. Implementing precision agriculture as a system will require education (from primary to tertiary institutions) and improved marketing strategies. Only then will precision technologies be able to help meet the future demands placed on the agriculture sector. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.
73

An analysis of precision agriculture in the South African summer grain producing areas / Hendriks J.

Hendriks, Joseph January 2011 (has links)
Both globally and locally, agriculture faces ever increasing challenges such as high input costs, strict environmental laws, decrease in land for cultivation and an increase in demand due to the growing global population. Profitability and sustainability requires more effective production systems. Precision agriculture is identified as such a system and is built upon a system approach that aims to restructure the total system of agriculture towards low input, high efficiency and sustainable agriculture. The aim of this study was to analyse the state of precision agriculture in the summer grain producing areas of South Africa, specifically the North West and Free State provinces. In order to achieve this, a literature study was conducted. During the literature study the term ‘precision agriculture’ was defined and discussed. The precision agriculture cycle and its components were explained and benefits of precision agriculture were identified. The literature study was concluded with identifying and discussing the most widely used and most beneficial technologies as well as reasons for slow adoption. Findings from the literature study were used to investigate the state of precision agriculture locally. In order to achieve this, a quantitative approach was used and information was collected by means of an empirical study using a questionnaire. Questionnaires were distributed to farmers using selling agents of an agricultural company that is well represented in the targeted areas. The data was then statistically analysed. The survey showed that only 52% of summer grain producing farmers in the North West and Free State provinces of South Africa practises precision agriculture as defined in the v literature study. The study also revealed that the majority of precision agriculture farmers are over the age of 40, have more than 16 years of farming experience, are well educated, cultivate more than 1,000 hectares and uses none or little irrigation. The most commonly used precision agriculture technologies were grid soil sampling and yield monitors. The perception among most of the farmers was that precision technologies are not very affordable, not easily available and that it lacks proper testing with regards to efficiency. The group of summer grain–producing farmers that have correctly implemented precision agriculture as per definition stated that the benefits they derived from precision technologies include reduction in input costs, increased outputs and improved management skills. Too high implementation costs and technologies not providing enough benefits were among the main reasons farmers do not implement precision agriculture. It was concluded that a significant effort and amount of work is needed to increase the use of precision agriculture among summer grain–producing farmers in the targeted areas. A consolidated effort from government, agricultural institutions and agricultural companies will be needed to achieve this goal. Implementing precision agriculture as a system will require education (from primary to tertiary institutions) and improved marketing strategies. Only then will precision technologies be able to help meet the future demands placed on the agriculture sector. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.

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