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Author: Karatay, Yusuf Nadi ×

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Now showing 1 - 4 of 4
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    Greenhouse Gas Mitigation Costs of Reduced Nitrogen Fertilizer
    (Basel : MDPI AG, 2022) Meyer-Aurich, Andreas; Karatay, Yusuf Nadi
    The reduction of nitrogen (N) fertilizer use is a possible greenhouse gas (GHG) mitigation option, whereas cost estimation highly depends on assumptions of the yield response function. This paper analyzes the potential and range of GHG mitigation costs with reduced N fertilizer application based on empirical yield response data for winter rye (Secale cereale L.) and rapeseed (Brassica napus L.) from field experiments from 2013 to 2020 in Brandenburg, Germany. The field experiments included four to five N rates as mineral fertilizer treatments. Three different functional forms (linear-plateau, quadratic, and quadratic-plateau) were estimated to model yield response as a function of N supply. Economic calculations were based on relevant price–cost ratios. The results indicate that the opportunity costs of applying less fertilizer and the resulting GHG mitigation thereof vary in a great range across the years and crops estimated by different yield response functions. The linear-plateau function predominantly results in lower GHG mitigation costs than the quadratic and the quadratic-plateau function. On average, over eight years, a moderate reduction of N fertilizer (up to 20 kg/ha) offers a cost-efficient option for mitigating GHG emissions below EUR 50 per ton of CO2eq, even resulting in net profit gain in some cases.
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    A model approach for yield-zone-specific cost estimation of greenhouse gas mitigation by nitrogen fertilizer reduction
    (Basel : MDPI, 2018) Karatay, Yusuf Nadi; Meyer-Aurich, Andreas
    Nitrogen use in agriculture has been intensified to feed the growing world population, which led to concerns on environmental harms, including greenhouse gas emissions. A reduction in nitrogen fertilization can abate greenhouse gas emissions, however, it may result in crop yield penalties and, accordingly, income loss. Assessment tools are necessary to understand the dynamics of nitrogen management issues both in environmental and economic aspects and both at low and high aggregation levels. Our study presents a model approach, estimating yield-zone-specific costs of greenhouse gas mitigation by moderate reduction of mineral nitrogen fertilizer application. Comparative advantages of mitigating greenhouse gas emissions by nitrogen fertilizer reduction were simulated for five yield-zones with different soil fertility in the state of Brandenburg, Germany. The results suggest that differences in yield response to nitrogen fertilizer lead to considerable differences in greenhouse gas mitigation costs. Overall cost-efficiency of a regional greenhouse gas mitigation by nitrogen fertilizer reduction can be substantially improved, if crop and yield-zone-specific yield responses are taken into account. The output of this study shall help to design cost-efficient agro-environmental policies targeting with specific crop yield response functions at different sites.
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    CUDe — Carbon utilization degree as an indicator for sustainable biomass use
    (Basel : MDPI, 2016) Anja Hansen, Anja Hansen; Budde, Jörn; Karatay, Yusuf Nadi; Prochnow, Annette
    Carbon (C) is a central element in organic compounds and is an indispensable resource for life. It is also an essential production factor in bio-based economies, where biomass serves many purposes, including energy generation and material production. Biomass conversion is a common case of transformation between different carbon-containing compounds. At each transformation step, C might be lost. To optimize the C use, the C flows from raw materials to end products must be understood. The estimation of how much of the initial C in the feedstock remains in consumable products and delivers services provides an indication of the C use efficiency. We define this concept as Carbon Utilization Degree (CUDe) and apply it to two biomass uses: biogas production and hemp insulation. CUDe increases when conversion processes are optimized, i.e., residues are harnessed and/or losses are minimized. We propose CUDe as a complementary approach for policy design to assess C as an asset for bio-based production. This may lead to a paradigm shift to see C as a resource that requires sustainable exploitation. It could complement the existing methods that focus solely on the climate impact of carbon.
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    Profitability of management systems on German fenlands
    (Basel : MDPI, 2016) Rebhann, Marco; Karatay, Yusuf Nadi; Filler, Günther; Prochnow, Annette
    Fens are organic sites that require drainage for agricultural use. Lowering the groundwater level leads to trade-offs between economic benefits and environmental impacts (i.e., CO2 and nutrient emissions). To identify management options that are both environmentally and economically sustainable, a propaedeutic systematic analysis of the costs, income and profit of different land use and management systems on fenlands is necessary. This study provides an overview of the profitability, labor demand and comparative advantages of feasible management systems on German fenlands. Twenty management practices in four land use systems are analyzed. The results indicate that most management systems are profitable only with subsidies and payments for ecosystem services. In addition to sales revenue, these payments are indispensable to promote peat-saving agricultural practices on fenlands. Regarding the labor aspect, intensive management systems caused an increase in working hours per hectare, which may positively affect employment in rural areas. The calculations obtained in this study can be used as a basis for estimations of greenhouse gas (GHG) mitigation costs when management systems are associated with GHG emission values.