Peer Reviewed Publications

  • Making Contract Farming Arrangements Work in Africa’s Bioeconomy: Evidence from Cassava Outgrower Schemes in Ghana

    17.05.2018

    Poku, A.-G., Birner, R., and S. Gupta (2018): Making Contract Farming Arrangements Work in Africa’s Bioeconomy: Evidence from Cassava Outgrower Schemes in Ghana. Sustainability 2018, 10(5), 1604; https://doi.org/10.3390/su10051604

    http://www.mdpi.com/2071-1050/10/5/1604

    Abstract

    This paper uniquely focuses on rapidly-developing domestic value chains in Africa’s emerging bioeconomy. It uses a comparative case study approach of a public and private cassava outgrower scheme in Ghana to investigate which contract farming arrangements are sustainable for both farmers and agribusiness firms. A complementary combination of qualitative and quantitative methods is employed to assess the sustainability of these institutional arrangements. The results indicate that ad hoc or opportunistic investments that only address smallholders’ marketing challenges are not sufficient to ensure mutually beneficial and sustainable schemes. The results suggest that firms’ capacity and commitment to design contracts with embedded support services for outgrowers is essential to smallholder participation and the long-term viability of these arrangements. Public-private partnerships in outgrower schemes can present a viable option that harnesses the strengths of both sectors and overcomes their institutional weaknesses.

    Keywords: contract farming; contract design; cassava; bioeconomy; Ghana

  • Risk governance of dams and family farms in Southwest Ethiopia in Land Use Policy

    16.05.2018

    Feye, G.L., Van Assche, K., Stellmacher, T., Tekleworld, H., and G. Kelboro (2018): Risk governance of dams and family farms in Southwest Ethiopia in Land Use Policyand colleagues published a paper called Land for food or power? Land Use Policy, Vol. 75:  50-59.

    Download here: https://www.sciencedirect.com/science/article/pii/S0264837717307470

  • Increasing the loading rate of continuous stirred tank reactor for coffee husk and pulp: Effect of trace elements supplement

    16.04.2018

    Chala, B., Oechsner, H., Fritz, T., Latif, S., and J. Müller (2018). Increasing the loading rate of continuous stirred tank reactor for coffee husk and pulp: Effect of trace elements supplement. Engineering in Life Science, https://doi.org/10.1002/elsc.201700168

    Abstract

    In this study, the anaerobic performance and stability of coffee husk and pulp with and without trace element (TE) supplement was investigated, using 20 L mesophilic continuous stirred tank reactors for 140 days of experiment (DOE). The TE was cocktail of trace metals composed of Fe, Ni, Zn, Co, Mn, Mo, Se W and B. The organic loading rate (OLR) was increased stepwise from 2.5 (HRT = 40 d) to 6.0 kg VS m¯³ d¯¹(HRT = 16.7 d). The highest methane productivity from pulp with and without TE was 1.272 and 0.965 m³ m¯³ d¯¹ at an OLR of 6.0 and 5.0 kg VS m¯³ d¯¹; while the husks performed 0.895 and 0.795 m³ m¯³ d¯¹ respectively, both at an OLR of 6.0 kg VS m¯³ d¯¹. The specific methane yield (SMY) of pulp (at OLR = 5 kg VS m¯³ d¯¹) with and without TEs was 217.9 ± 4.7 and 193.1 ± 8.2 L kg¯¹ VS; while husk yielded 149.2 ± 6.0 and 132.5 ± 4.9 L kg¯¹ VS, respectively. The effect of TEs on SMY was statistically significant (p < 001) at higher OLRs (5.0 ‐ 6.0 kg VS m¯³ d¯¹). The TEs improved the anaerobic stability through an optimum alkalinity ratio (VFA/TIC < 0.3) and suppressed the accumulation of volatile fatty acids. Mono digestion of husks and pulp are prone to lack Mo, Zn, Ni and Fe in long‐term anaerobic fermentation. Further studies on co‐digestion of husk/pulp with animal manure and dry fermentation helps to efficiently use this biomass resource.

  • Nikinake: the mobilization of labour and skill development in rural Ethiopia

    13.03.2018

    Gerba Leta , Girma Kelboro, Till Stellmacher, Kristof Van Assche
    and, Anna-Katharina Hornidge (2018): Nikinake: the mobilization of labour and skill development in rural Ethiopia. Natural Resources Forum. doi:10.1111/1477-8947.12145

    Find article here: http://onlinelibrary.wiley.com/doi/10.1111/1477-8947.12145/full

    Abstract

    A public mobilization approach known as nikinake drives implementation and technology upscaling in Ethiopia’s agricultural extension. This study investigates and describes the processes and effectiveness of nikinake as an extension method used for natural resource management (NRM). The paper draws on empirical field research conducted in Oromia and the southern region of Ethiopia by looking at nikinake in the context of a watershed management campaign in 2015 and 2016. Nikinake is used as an approach to mobilize the public and to promote the skills of farmers and development actors. In principle, the implementation of NRM is voluntary; however, it is largely planned top-down and enforced through state actors and informal institutions. This study suggests effective integration of social mobilization with reliable extension and a paradigm shift in emphasis from spatial coverage to an effective outcome. Additionally, sustainability and scalability of NRM interventions could be ameliorated by improving experts’ technical skills, raising farmers’ awareness, improving an incentive system, building trust, and better integrating past watershed management and future planning activities. We reflect on the significance of the nikinake experience in Ethiopia for a broader theory of extension-as-mobilization for rural development. From the Ethiopian case, a more general recommendation emerges for extension-as-mobilization schemes. For long-term development, it is worthwhile to consider the fit between yearly campaigns as ad hoc project organizations and the existing pattern of actors and institutions responsible for rural development.

    Keywords

    Agricultural extension; collective action; governance; nikinake; participation

     

  • Organic and conventional agriculture in Kenya: A typology of smallholder farms in Kajiado and Murang’a counties.

    07.02.2018

    Juliet Wanjiku Kamau, Till Stellmacher, Lisa Biber-Freudenberger, Christian Borgemeister (2018): Organic and conventional agriculture in Kenya: A typology of smallholder farms in Kajiado and Murang’a counties. Journal for Rural Studies. Elsevier. Volume 57, 171-185. https://doi.org/10.1016/j.jrurstud.2017.12.014

    Find article here: https://ac.els-cdn.com/S0743016717301857/1-s2.0-S0743016717301857-main.pdf?_tid=b7cd5df6-0be5-11e8-85d1-00000aacb35d&acdnat=1517994369_21778aaf36fb59b6137639e6b2d1be9d

    Abstract

    Understanding the diversity of smallholder farms is key for the development of interventions, strategies and policies aimed at addressing the numerous challenges these farmers face as well as for those shaping the future of smallholder farming in Kenya, Africa and beyond. In this study, we developed a typology for smallholder farms in Kenya using survey data from 488 farm households in Kajiado and Murang’a counties. Multivariate statistical techniques (principal component and cluster analyses) were used to group farms into five types differentiated by household characteristics, resource endowment, cropping practices, social networks, access to information, dietary diversity and gender equity. Types 2, 3 and 5 were mostly market oriented, possessed high to medium levels of wealth and had strong social networks. Types 3 and 5, however, mainly practised organic agriculture while Type 2 farms included organic and non-organic cultivated areas. Types 1 and 4 were characterised by low to medium levels of wealth, maintained poor social networks and had low adherence to organic agriculture practices. Yet, while Type 4 farms mainly practised conventional market-oriented agriculture, farms of Type 1 could be defined as organic-by-default and were self-subsistent. The majority of the surveyed farms belonged to Type 2, the wealthiest group of farmers and mostly located in Kajiado county. Murang’a county was dominated by farms of Type 5 practising mainly certified organic agriculture. Overall, the practice of organic agriculture was associated with higher agricultural income, legal ownership of land, older household heads, larger household sizes, stronger social networks, higher access to information, more diverse diets and higher levels of gender equity. In contrast, poorer, younger and less well-connected farmers were less involved in organic agriculture. The results of this study may help to increase efficiency in the implementation of pro-poor and organic agricultural interventions, strategies and policies on the ground and to shape policy instruments accordingly.

    Keywords

    Diversity; Poverty; Food security; Organic agriculture; Multivariate analysis; Participatory guarantee systems

  • Rapid and easy carotenoid quantification in Ghanaian starchy staples using RP-HPLC-PDA

    15.01.2018

    Wald, Julian P., Nohr, Donatus, and Hans K. Biesalski 2018. Rapid and easy carotenoid quantification in Ghanaian starchy staples using RP-HPLC-PDA. Journal of Food Composition and Analysis, 67:119–127. https://doi.org/10.1016/j.jfca.2018.01.006

    https://www.sciencedirect.com/science/article/pii/S0889157518300061

    Abstract

    This study comprises the development of a robust, rapid and cost-effective reversed-phase high-performance liquid chromatographic method with low solvent consumption (micro-approach) to quantify carotenoids in starchy staples, exemplified for cassava, maize and plantain matrices. For extraction, a mixture of 1 M potassium hydroxide in methanol and hexane (1:1) was used, enabling the simultaneous extraction and saponification of the sample extracts. Carotenoids were separated within 12 min on a C30 column using mixtures of methanol, methyl tert-butyl ether and water as mobile phases. Due to the implemented saponification process, the technique showed the potential to be applied for carotenoid analysis in other sample matrices exemplarily demonstrated for green leafy vegetables. Because of the low application and equipment costs, the analytical procedure qualifies for its application in quality management with limited budget. Concentrations of five major dietary carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene and β-carotene) in cassava, cocoyam, yam, maize and plantain samples from the Ashanti region of Ghana were determined. Based on the restricted data on carotenoid contents of food available in West Africa, the results provide valuable additional information that can be used to expand local food composition tables and support the assessment of dietary carotenoid intake.

    Keywords

    Food analysis; Food composition; Starchy staples; Cassava; Maize; Plantain; Carotenoids; Provitamin A; β-Carotene; HPLC

  • Why do maize farmers in Ghana have a limited choice of improved seed varieties? An assessment of the governance challenges in seed supply

    15.01.2018

    Poku, Adu-Gyamfi, Birner, Regina, and Saurabh Gupta 2018. Why do maize farmers in Ghana have a limited choice of improved seed varieties? An assessment of the governance challenges in seed supply. Food Security. https://doi.org/10.1007/s12571-017-0749-0.

    https://link.springer.com/article/10.1007%2Fs12571-017-0749-0

    Abstarct

    The liberalisation of commercial seed systems has largely been seen as an essential means of improving agricultural productivity in Sub-Saharan Africa. Yet, access to improved seed varieties has remained a major constraint in many countries in spite of liberalisation and other reform efforts. This paper analyses the governance challenges involved in seed systems from a theoretical and an empirical perspective. The paper applies theoretical concepts of New Institutional Economics to identify potential governance challenges involved at the different stages of the seed supply system. The commercial maize seed sector in Ghana is used for an empirical case study. Ghana has passed a seed law that aims to increase the availability of improved seed varieties to farmers by providing more opportunities to the private sector. However, there is still a chronic lack of varietal diversity, indicating that governance challenges in the seed system remain despite the reform efforts. For data collection, a participatory mapping technique known as Process Net-Map was applied, together with expert interviews involving a diverse set of stakeholders. The empirical evidence reveals that, in line with the theoretical considerations, governance challenges indeed affect all stages of the seed supply system. These challenges include limited involvement of smallholders in setting breeding priorities, restricted private sector participation in source seed production, limited ability of an under-resourced public regulatory body to ensure high seed quality through mandatory seed certification and overdependence on a weak public extension system to promote improved varieties. The paper discusses the policy implications of the findings.

    Keywords

    Seed systems; Governance challenges; Varietal development; Seed production; Seed quality; Ghana

     

  • From commodity-based value chains to biomass-based value webs: The case of sugarcane in Brazil’s bioeconomy

    23.06.2017

    Scheiterle, L., Ulmer, A., Birner, R., and Andreas Pykab 2017. From commodity-based value chains to biomass-based value webs: The case of sugarcane in Brazil’s bioeconomy. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2017.05.150

    http://www.sciencedirect.com/science/article/pii/S0959652617310934

    Abstract
    The shift from a fossil-based to a bio-based economy (bioeconomy) requires more efficient utilization of the biomass generated from agricultural production. This can be achieved through the cascading use of biomass, which also offers the potential of creating additional value from biomass by developing novel products. Taking sugarcane as a case study example, this paper aims to analyze how well Brazil, the world’s leader in sugarcane production, is positioned to reach these goals. The paper combines two conceptual tools: one is the ‘biomass-based value web’, which was developed as an extension of the value chain concept with the aim to capture the links within and between value chains that arise from the cascading and joined use of biomass. The other concept is that of the ‘national innovation system’ (NIS), which serves to identify the different types of actors involved in the biomass value web and the linkages between them. For empirical data collection, the study combined three methods: a mapping of the physical biomass flows in the value web, in-depth interviews with the actors involved, and the application of the ‘Net-Map’ tool to identify the actors in the NIS and their linkages. The findings show that the development of Brazil’s international competitiveness in sugar and ethanol was based on political incentives that resulted in a strong network of institutions that focused on these two products. However, to become a front-runner in the future bioeconomy, the existing innovation network needs to be expanded. In particular, it is important to integrate national and international private sector organizations. The findings also suggest that industries need stronger incentives to collaborate with knowledge institutions. Long-term consistent policies and funding opportunities for risky investments are also required to further strengthen Brazil’s innovation network to meet future opportunities and challenges of the bioeconomy.

    Keywords
    Bioeconomy; Biomass value web; Innovation system; Brazil; Sugarcane

  • How does inter-annual variability of attainable yield affect the magnitude of yield gaps for wheat and maize? An analysis at ten sites.

    23.06.2017

    M.P. Hoffmann, M. Haakana, S. Asseng, J.G. Höhn, T. Palosuo, M. Ruiz-Ramos, S. Fronzek, F. Ewert, T. Gaiser, B.T. Kassie, K. Paff, E.E. Rezaei, A. Rodríguez, M. Semenov, A.K. Srivastava, P. Stratonovitch, F. Taob,i, Y. Chen,j, R.P. Rötter 2017. How does inter-annual variability of attainable yield affect the magnitude of yield gaps for wheat and maize? An analysis at ten sites. Agricultural Systems. https://doi.org/10.1016/j.agsy.2017.03.012

    http://www.sciencedirect.com/science/article/pii/S0308521X16305947

    Abstract
    Provision of food security in the face of increasing global food demand requires narrowing of the gap between actual farmer’s yield and maximum attainable yield. So far, assessments of yield gaps have focused on average yield over 5–10 years, but yield gaps can vary substantially between crop seasons. In this study we hypothesized that climate-induced inter-annual yield variability and associated risk is a major barrier for farmers to invest, i.e. increase inputs to narrow the yield gap.
    We evaluated the importance of inter-annual attainable yield variability for the magnitude of the yield gap by utilizing data for wheat and maize at ten sites representing some major food production systems and a large range of climate and soil conditions across the world. Yield gaps were derived from the difference of simulated attainable yields and regional recorded farmer yields for 1981 to 2010. The size of the yield gap did not correlate with the amplitude of attainable yield variability at a site, but was rather associated with the level of available resources such as labor, fertilizer and plant protection inputs. For the sites in Africa, recorded yield reached only 20% of the attainable yield, while for European, Asian and North American sites it was 56–84%. Most sites showed that the higher the attainable yield of a specific season the larger was the yield gap. This significant relationship indicated that farmers were not able to take advantage of favorable seasonal weather conditions. To reduce yield gaps in the different environments, reliable seasonal weather forecasts would be required to allow farmers to manage each seasonal potential, i.e. overcoming season-specific yield limitations.

    Keywords
    Inter-annual yield variability; Yield gap analysis; Wheat; Maize; Climate-induced risk

  • Climate change impact under alternate realizations of climate scenarios on maize yield and biomass in Ghana.

    23.06.2017

    Amit Kumar Srivastava, Cho Miltin Mboh, Gang Zhao, Thomas Gaiser, Frank Ewert 2017. Climate change impact under alternate realizations of climate scenarios on maize yield and biomass in Ghana. Agricultural Systems

    http://www.sciencedirect.com/science/article/pii/S0308521X16305194

    Abstract
    Climate change is unequivocal and these changes have increased over the past few years. The recent vulnerability and prospect of climate variability and change impact, thus, warrants measures now to reduce the adverse impacts. This study presents an estimate of the effects of climate variables on potential maize productivity and an assessment of the most limiting climatic drivers in the future climate scenarios for maize production in central Ghana, constituting major maize production areas. The time-slices 2000, 2030 and 2080 were chosen to represent the baseline, near future and end century climate, respectively. Furthermore, two Representative Concentration Pathways (RCPs) namely RCP 4.5 and RCP 8.5 from the GFDL-ESM2M, GISS-E2-H, and HadGEM2-ES, General Circulation Models (GCMs), were selected. Simulations based on the model LINTUL5 were used to estimate the crop responses.
    There is an average increase in the maize yield and aboveground biomass in the projected scenarios by 57% and 59% respectively under HadGEM2-ES (RCP 8.5) in the time horizon 2030. However, variability in the projected average maize yield and above ground biomass compared to the baseline values, is ranging from 183.6 kg ha− 1 under HadGEM2-ES (RCP 8.5) by time horizon 2080 to a maximum of 1326.8 kg ha− 1 under HadGEM2-ES (RCP 8.5) by 2030 and a minimum increase of 169.9 kg ha− 1 under GFDL-ESM2M (RCP 8.5) by time horizon 2080 to a maximum increase of 2386.1 kg ha− 1 under HadGEM2-ES (RCP 8.5) by time horizon 2030.
    The reasons for potential benefit in maize yields across the climate scenarios was attributed to the positive effect of CO2, reduced water stress reflected by lower atmospheric water demand during crop growth period. It also indicates that water is the limiting factor for maize production in the study region. However, temperature (through shortening of the maize growing cycle), and solar radiation may remain the limiting factors for maize production.

    Keywords
    Maize; Sub-Saharan Africa; Climate change; Autonomous adaptation

  • Screening of some cassava starches for their potential applications in custard and salad cream productions.

    23.06.2017

    Akinwale, T. E., Niniola, D. M., Abass, A., Shittu, T., Adebowale, A., Awoyale, W., Awonorin, S., Adewuyi, S. & Eromosele, C. O. (2017) Screening of some cassava starches for their potential applications in custard and salad cream productions. Journal of Food Measurement and Characterization, 11: 299-309.  doi:10.1007/s11694-016-9397-x

    Abstract
    Custard powder and salad cream are two food products commercially manufactured using different quantities of corn starch. This study aimed at determining the physicochemical properties of some starches extracted from some white and yellow root cassava varieties. The prospective applicability of the cassava starches in custard powder and salad cream production was also determined. The physical, chemical and functional properties of eight cassava starches were determined using standard analytical procedures. Sensory acceptability of the products was also determined using untrained consumer group. Products made from corn starch were used as the reference samples. The physical, chemical and functional properties of the cassava starches varied significantly (p < 0.05). The results of multivariate data analysis (principal component and cluster analyses) showed that it was difficult to completely discriminate starches from the yellow fleshed and white fleshed cassava roots. Texture was the most important sensory attribute determining the two products’ acceptability. Starch powder dispersibility was found to have significant influence (p < 0.05) on the sensory acceptability of the two products. However, starch from a yellow fleshed root (TMS 01/1368) was the most preferred for salad cream making while starch from a white fleshed root (TMS 30572) was the most preferred for making custard powder. The starches showed high potential to replace corn starch for the respective product manufacture.

    Keywords
    Salad cream Custard powder Cassava starch Sensory acceptability

    https://link.springer.com/article/10.1007/s11694-016-9397-x

  • Assessment of the potential industrial applications of commercial dried cassava products in Nigeria.

    23.06.2017

    Awoyale, W., Abass, A., Ndavi, M., Maziya-Dixon, B. & Sulyok, M. (2016) Assessment of the potential industrial applications of commercial dried cassava products in Nigeria. IN Journal of Food Measurement and Characterization, 1— 12. doi:10.1007/s11694-016-9428-7

    https://link.springer.com/article/10.1007/s11694-016-9428-7

    Abstract
    Variations in the functional and pasting properties of four groups of commercial dried cassava product in Nigeria were evaluated in this study, to explore their potential for use as industrial raw materials. In total, 692 products were analyzed using standard analytical methods. The functional and pasting properties of the samples were found to vary significantly (p < 0.05). Toasted cassava was found to have the highest water absorption capacity, at 467.42 %, and dried cassava the lowest, at 252.57 %. Conversely, dried cassava was found to have the highest peak and breakdown viscosities, and toasted cassava the lowest. A significant (p < 0.01) positive correlation was found to exist between dispersibility and the swelling power (r = −0.93) and solubility index (r = −0.84) of the cassava products. Meanwhile, the correlation between dispersibility and the peak (r = −0.75) and breakdown (r = −0.72) viscosities was positive and significant (p < 0.05). Therefore, the authors of this study conclude that user industries such as the food, paper, adhesives, textiles and plywood sectors might require information on the pre-processing of cassava-based feedstock, so as to predetermine the technical usability of such raw materials within their industrial processes.

    Keywords
    Cassava products Processing methods Functional properties Pasting properties Nigeria

  • Potentials of Bamboo-Based Agroforestry for Sustainable Development in Sub-Saharan Africa: A Review

    20.01.2017

    Partey, S.T. , Sarfo, D.A., Frith, O., Kwaku, M., and Naresh V. Thevathasan (2017): Potentials of Bamboo-Based Agroforestry for Sustainable Development in Sub-Saharan Africa: A Review. Agricultural Research, doi:10.1007/s40003-017-0244-z

    Abstract
    There is widespread assertion among scientists, government and development experts that bamboo agroforestry could contribute to sustainable rural development in Sub-Saharan Africa (SSA). However, there are limited available data to verify the suitability of the system in the region. In addition, the current state of knowledge and adoption of agroforestry in SSA offers very little guidance as to which type of agroforestry systems bamboo could be integrated. Here, we reviewed the potential socioeconomic and environmental benefits of bamboo agroforestry and accentuate implications on sustainable rural development in SSA. In addition, we analysed potential research areas that could be intensified, so that future developments and scaling-up of bamboo agroforestry can be rooted in robust scientific findings rather than the intuitions of governments and development actors.

    Keywords
    Agroforestry, Deforestation, Land-use systems, Ecosystem services, Bamboo, Sustainability, Africa

    View full article here

  • Impact of climatic variables on the spatial and temporal variability of crop yield and biomass gap in Sub-Saharan Africa – a case study in Central Ghana.

    PDF | 11.01.2017

    Srivastava, A.K., Mboh, C.M., Gaiser, T., and F. Ewert (2017): Impact of climatic variables on the spatial and temporal variability of crop yield and biomass gap in Sub-Saharan Africa – a case study in Central Ghana. Field Crops Research, 203, 33-46.

    http://www.sciencedirect.com/science/article/pii/S0378429016307183

  • Comparative life cycle analysis of producing charcoal from bamboo, teak, and acacia species in Ghana

    14.11.2016

    Partey, Samuel T. , Oliver B. Frith, Michael Y. Kwaku, and Daniel A. Sarfo (2016): Comparative life cycle analysis of producing charcoal from bamboo, teak, and acacia species in Ghana. International Journal of Life Cycle Assessment pp. 1-9.

    Abstract

    Background, aim, and scope The rise in wood fuel consumption, particularly of charcoal, has been associated with increased deforestation in Ghana. Plantation developments from teak (Tectona grandis), bamboo (Bambusa balcooa), and Acacia auriculiformis are now being promoted to produce sustainable biomass for charcoal production. While all species have comparable charcoal quality, there is limited available data to elucidate the environmental impacts associated with their plantation development and use as biomass sources for producing charcoal. Therefore, this study quantified and compared the cradle-to-gate environmental impacts of producing charcoal from T. grandis, A. auriculiformis, and B. balcooa.
    Methods The study was conducted in accordance with ISO 14040/14044, an international procedural framework for performing life cycle analysis (LCA). For this study, the functional unit of charcoal used was 1 MJ energy produced from three species: T. grandis, A. auriculiformis, and B. balcooa.
    Data on B. balcooa plantations was collected from a B. balcooa-based intercropping system set up by the International Network for Bamboo and Rattan in Sekyere Central District, Ghana. Input data for A. auriculiformis and T. grandis came from the Forestry Commission of Ghana plantations established within the forest agroecological zone of Ghana. All input data came from primary local sources.
    Pollutant emissions were also calculated in order to analyze the contribution of all the flow processes to the emissions. The analysis used Simapro version 8, as well as life cycle inventory (LCI) databases of Ecoinvent V3 and Idemat 2015 (a database developed by Delft University of Technology, the Netherlands). The emissions were expressed as eco-costs and used as indicators in an impact assessment.
    Results and discussion The results showed that relative to B. balcooa, the total eco-cost (comprising of human health, ecosystem, resource depletion, and global warming eco-costs) of a cradle-to-gate production of 1 MJ of charcoal will be 140% higher with T. grandis and 113% higher with A. auriculiformis. The increased environmental impacts associated with T. grandis and A. auriculiformis occurred at their biomass production stage. As these species use comparatively large quantities of pesticides, weedicides, and fertilizers with high acidification, ozone depletion, and global warming potentials, their biomass production stage accounted for
    approximately 85% of their total eco-cost.
    Conclusions The study results suggest that B. balcooa plantations are the most environmentally viable option. In cases where T. grandis or A. auriculiformis plantations are widespread, improvement options at the biomass production stage are required in order to reduce their environmental costs.

    Go to article: http://link.springer.com/article/10.1007/s11367-016-1220-8

  • Food security criteria for voluntary biomass sustainability standards and certifications

    31.08.2016

    Mohr, A., Beuchelt, T. Schneider, R., Virchow, D. 2016. Food security criteria for voluntary biomass sustainability standards and certifications. Biomass and Bioenergy 89, pp. 133–145.

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  • A critical review of the follow-the-innovation approach: Stakeholder collaboration and agricultural innovation development

    PDF | 22.08.2016

    Amankwah, K., Shtaltovna, A., Kelboro, G. and A.-K. Hornidge. 2016. A critical review of the follow-the-innovation approach: Stakeholder collaboration and agricultural innovation development. African Journal of Rural Development, 1: 35-49. (Open Access)

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  • Effect of self-purging pyrolysis on yield of biochar from maize cobs, husks and leaves

    12.07.2016

    Intani, K., Latif, S., Kabir, A.K.M.R., Müller, J., 2016. Effect of
    self-purging pyrolysis on yield of biochar from maize cobs, husks and
    leaves. Bioresource Technology, 218, 541–551.
    doi:http://dx.doi.org/10.1016/j.biortech.2016.06.114

    URL: http://www.sciencedirect.com/science/article/pii/S0960852416309385

    Download link (until August 27, 2016):
    http://authors.elsevier.com/a/1TLCn3QUFYzAY9

    Abstract: In this study, biochar was produced from maize residues (cobs, husks, leaves) in a lab-scale pyrolysis reactor without using a purging gas. The physicochemical properties of biomass and biochar were analysed. Box–Behnken design was used to optimise operational conditions for biochar yields. Multivariate correlations of biochar yields were established using reduced quadratic models with R2 = 0.9949, 0.9801 and 0.9876 for cobs, husks and leaves, respectively. Biochar yields were negatively correlated with the temperature, which was significantly influenced by the exothermic reactions during the pyrolysis of maize residues. The heating rate was found to have the least effect on biochar yields. Under optimal conditions, the maximum biochar yields from cobs, husks and leaves were 33.42, 30.69 and 37.91%, respectively. The highest biochar yield from maize leaves was obtained at a temperature of 300 °C, a heating rate of 15 °C/min and a holding time of 30 min.

  • Effect of sowing date distributions on simulation of maize yields at regional scale – A case study in Central Ghana, West Africa

    07.06.2016

    Srivastava, A. K., Mboh, C. M., Gaiser, T., Webber, H., & Ewert, F. (2016). Effect of sowing date distributions on simulation of maize yields at regional scale–A case study in Central Ghana, West Africa. Agricultural Systems, 147, 10-23.

    Download article : Srivastava_etal_2016

  • Modelling heat stress effect on two maize varieties in Northern Region of Ghana

    15.10.2015

    Trawally, D.M.A, Webber, H., Agyare, W.A., Fosu, M., Naab, J., Gaiser, T. 2015: Modelling heat stress effect on two maize varieties in Northern Region of Ghana. Global Advanced Research Journal of Agricultural Science 4: 145-155

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  • Protected areas as contested spaces: Nech Sar National Park, Ethiopia, between ‘local people’, the state, and NGO engagement

    05.06.2015

    Kelboro, Girma and Till Stellmacher.
    2015: Protected areas as contested spaces: Nech Sar National Park, Ethiopia, between ‘local people’, the state, and NGO engagement. Environmental Development. Elsevier, doi:10.1016/j.envdev.2015.06.005

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  • Potential of cassava leaves in human nutrition: a review

    04.05.2015

    Latif, Sajid and Joachim Müller 2015. Potential of cassava leaves in human nutrition: a review, Trends in Food Science & Technology 44 (2015), pp. 147-158, doi: 10.1016/j.tifs.2015.04.006

     

    http://www.sciencedirect.com/science/article/pii/S0924224415000990

  • Effect of sowing date and nitrogen fertilizer application on the growth, yield and biomass production of two maize varieties under irrigated and rainfed conditions in Northern Region of Ghana

    15.12.2014

    Trawally, D., Webber, H.A., Agyare, W.A., Fosu, M., Naab, J., Gaiser, T. 2014: Effect of sowing date and nitrogen fertilizer application on the growth, yield and biomass production of two maize varieties under irrigated and rainfed conditions in Northern Region of Ghana. International Journal of Biological and Chemical Sciences 9: 1571-1587.

     

  • Using the concepts of resilience, vulnerability and adaptability for the assessment and analysis of agricultural systems

    15.12.2014

    Callo-Concha, D., Ewert, F. 2014: Using the concepts of resilience, vulnerability and adaptability for the assessment and analysis of agricultural systems. Change and Adaptation in Socio-Ecological Systems 1(1): 1-11, DOI:10.2478/cass-2014-0001

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  • From food insufficiency towards trade-dependency: a historical analysis of global food availability

    15.12.2013

    Porkka, M., Kummu, M., Siebert, S., Varis, O. 2013: From food insufficiency towards trade-dependency: a historical analysis of global food availability. PLoS ONE 8, e82714, DOI:10.1371/journal.pone.0082714.

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