Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    N2Africa Annual Report 2019
    Dontsop-Nguezet, Paul M. ; Ampadu-Boakye, Theresa ; Ronner, E. ; Baars, Edward ; Kanampiu, Fred ; Giller, K.E. ; Vanlauwe, B. ; Adjei-nsiah, Samuel ; Wolde-Meskel, E. ; Ebanyat, Peter ; Baijukya, Frederick ; Dianda, M. ; Sanginga, Jean-Marie ; Woomer, P.L. ; Chikowo, Regis ; Phiphira, Lloyd ; Kantengwa, Speciose ; Leonardo, W. ; Kamai, Nkeki ; Thuijsman, E.C. ; Schilt-van Ettekoven, C. - \ 2019
    Wageningen : N2Africa (N2Africa project report 120) - 78 p.
    Annual report, Key milestones, objectives, progress, biological nitrogen fixation, grain legumes, Nigeria, Borno State, Ghana, Tanzania, Ethiopia, Uganda, DR Congo, Rwanda, Kenya, Malawi, Zimbabwe, Mozambique
    Responses to inoculation of Phaseolus beans on N2Africa trials in Ethiopia, Tanzania, Rwanda and Zimbabwe
    Thuijsman, E.C. ; Ronner, E. ; Wolde-Meskel, E. ; Kantengwa, Speciose ; Rurangwa, E. ; Chikowo, Regis ; Chekanai, Vongai ; Baijukya, Frederick ; Giller, K.E. - \ 2019
    Wageningen : N2Africa (N2Africa project report 118) - 12 p.
    Annual report - Key milestones - objectives - progress - biological nitrogen fixation - grain legumes - Nigeria - Borno State - Ghana - Tanzania - Ethiopia - Uganda - DR Congo - Rwanda - Kenya - Malawi - Zimbabwe - Mozambique
    Studies on responses to inoculation in bush bean(Phaseolus vulgaris) were carried out as part of the N2Africa project (www.n2africa.org) in Ethiopia, Tanzania, Rwanda and Zimbabwe.Inoculant treatments without fertilizer inputs significantly improved yields by 0.27 t ha-1compared to the unamended control in Ethiopia. The combined effect of inoculation and P fertilization was much larger and significant in all four countries. Trials in Tanzania and in Zimbabwe also included the application of N fertilizer, and manure was included on the trials in Rwanda. Largest yields were achieved when inoculant and fertilizer inputs were combined. Inoculation tended to boost responses to fertilizer inputs in Ethiopia, Rwanda and Tanzania. Detailed results per country are given below.
    N2Africa Annual Report 2018
    Ampadu-Boakye, Theresa ; Ronner, E. ; Kanampiu, Fred ; Giller, K.E. ; Baars, Edward ; Vanlauwe, B. ; Adjei-nsiah, Samuel ; Wolde-Meskel, E. ; Ebanyat, Peter ; Baijukya, Frederick ; Sanginga, Jean-Marie ; Woomer, P.L. ; Chikowo, Regis ; Phiphira, Lloyd ; Kantengwa, Speciose ; Leonardo, W. ; Kamai, Nkeki ; Thuijsman, E.C. ; Schilt-van Ettekoven, C. - \ 2019
    Wageningen : N2Africa (N2Africa project report 111) - 77 p.
    Annual report, Key milestones, objectives, progress, biological nitrogen fixation, grain legumes, Nigeria, Borno State, Ghana, Tanzania, Ethiopia, Uganda, DR Congo, Rwanda, Kenya, Malawi, Zimbabwe, Mozambique
    From best fit technologies to best fit scaling: incorporating and evaluating factors affecting the adoption of grain legumes in Sub-Saharan Africa
    Farrow, Andrew ; Ronner, Esther ; Brand, Greta J. van den; Boahen, Stephen K. ; Leonardo, Wilson ; Wolde-Meskel, Endalkachew ; Adjei-Nsiah, Samuel ; Chikowo, Regis ; Baijukya, Fredrick ; Ebanyat, Peter ; Sangodele, Emmanuel A. ; Sanginga, Jean-Marie ; Kantengwa, Speciose ; Phiphira, Lloyd ; Woomer, Paul ; Ampadu-Boakye, Theresa ; Baars, Edward ; Kanampiu, Fred ; Vanlauwe, Bernard ; Giller, Kenneth E. - \ 2019
    Experimental Agriculture 55 (2019)S1. - ISSN 0014-4797 - p. 226 - 251.
    The success of scaling out depends on a clear understanding of the factors that affect adoption of grain legumes and account for the dynamism of those factors across heterogeneous contexts of sub-Saharan Africa. We reviewed literature on adoption of grain legumes and other technologies in sub-Saharan Africa and other developing countries. Our review enabled us to define broad factors affecting different components of the scaling out programme of N2Africa and the scales at which those factors were important. We identified three strategies for managing those factors in the N2Africa scaling out programme: (i) testing different technologies and practices; (ii) evaluating the performance of different technologies in different contexts; and (iii) monitoring factors that are difficult to predict. We incorporated the review lessons in a design to appropriately target and evaluate technologies in multiple contexts across scales from that of the farm to whole countries. Our implementation of this design has only been partially successful because of competing reasons for selecting activity sites. Nevertheless, we observe that grain legume species have been successfully targeted for multiple biophysical environments across sub-Saharan Africa, and to social and economic contexts within countries. Rhizobium inoculant and legume specific fertiliser blends have also been targeted to specific contexts, although not in all countries. Relatively fewer input and output marketing models have been tested due to public–private partnerships, which are a key mechanism for dissemination in the N2Africa project.
    Review of policies relating to legume intensification in N2Africa countries
    Stadler, Minke ; Giller, K.E. ; Kanampiu, Fred ; Sangodele, Emmanuel A. ; Ebanyat, Peter ; Wolde-Meskel, Endalkachew ; Baijukya, Frederick ; Adjei-Nsiah, S. ; Sanginga, Jean-Marie ; Kantengwa, Speciose ; Woomer, P.L. ; Chikowo, Regis ; Phiphira, Lloyd ; Leonardo, W. ; Kamai, Nkeki ; Schilt-van Ettekoven, C. - \ 2017
    N2Africa project (N2Africa project report 107) - 38 p.
    The ‘N2Africa Review of policies relating to legume intensification in N2Africa counties’ showed that governments in N2Africa countries acknowledge the importance of legume intensification and its significant potential to contribute to improving food security and health, especially for poor families.
    At global level, the seventeen Sustainable Development Goals (SDGs) of the 2030 Agenda for Sustainable Development developed by the United Nations (UN) aim to end all forms of poverty, fight inequalities and tackle climate change, while ensuring that no one is left behind. The SDGs recognize that ending poverty must go hand-in-hand with strategies that build economic growth and addresses a range of social needs including education, health and job opportunities, amongst others. Governments are expected to take ownership and establish national frameworks for the achievement of the seventeen goals. Particularly, SDG2 ‘End hunger achieve food security and improved nutrition and promote sustainable agriculture’ seeks sustainable solutions to end hunger in all its forms and to achieve food security. It entails improving the productivity and incomes of small-scale farmers by promoting equal access to land, technology and markets, sustainable food production systems and resilient agricultural practices.
    The Comprehensive Africa Agriculture Development Programme (CAADP) is the pan-African policy framework for agricultural transformation, wealth creation, food security and nutrition, economic growth and prosperity for all. The CAADP Results Framework 2015 – 2025 is prepared by the Food and Agriculture Organisation (FAO) of the UN in cooperation with the New Partnership for Africa’s Development (NEPAD) Steering Committee. It recognizes the importance of increasing yield of food grains, tubers and legumes to catalyse transformation of Africa’s agricultural systems and presents critical actions required to achieve agricultural development agenda targets. Furthermore, the Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA) serves as a platform for promoting regional research and in the sharing of benefits and spillovers that derive from such research. The association focuses on four thematic areas that are well aligned to the major ongoing regional and continental initiatives. These include (i) Integrated capacity strengthening, (ii) Development and scaling up of technologies and innovations, (iii) Policy advocacy, market analysis and institutional arrangement, (iv) Knowledge and information management. High yielding climbing bean varieties and training on different staking options are included in ASARECA projects that scale up best practices to address farmers’ needs.
    National governments in the N2Africa countries all developed national policies aimed at increasing agricultural productivity, improving food security, diversifying food production to improve nutrition, and increasing agricultural incomes of the rural people. All national policies refer to legumes, mostly indirectly (e.g. intercropping practices, as measure for soil fertility, amongst others). Table 1 presents the N2Africa target legumes mentioned in national policies per N2Africa country.

    All national policies aim at increasing the production and productivity of various legumes by various strategies, such as (i) adopting modern production techniques, (ii) strengthening coordination, institutional capacity and skills across the key actors, (iii) providing timely and appropriate market entry support for effective market development and (iv) scaling up production and trade, amongst others. Rhizobia are only referred to in a few national policies (e.g. Ethiopia, Kenya, Malawi and Rwanda). The Tanzanian government is the only government that developed an explicit policy tool to promote the pulses sector (e.g. common bean, cowpea, pigeonpea, green gram and chickpea, mung bean and Bambara nut).
    The study results will be completed and used to provide recommendations to governments about best-fit legume technologies, how to increase production and productivity of various legumes and how to stimulate farmers’ use.
    N2Africa Project Zimbabwe Exit Strategy
    Chikowo, R. ; Chabata, I. ; Giller, K.E. - \ 2017
    Wageningen : N2Africa (Project report N2Africa 105) - 15 p.
    Can sub-Saharan Africa feed itself?
    Ittersum, M.K. van; Bussel, L.G.J. van; Wolf, J. ; Grassini, Patricio ; Wart, Justin van; Guilpart, Nicolas ; Claessens, L.F.G. ; Groot, H.L.E. de; Wiebe, Keith ; Mason-d’Croz, Daniel ; Yang, Haishun ; Boogaard, H.L. ; Oort, P.A.J. van; Loon, M.P. van; Saito, Kazuki ; Adimo, Ochieng ; Adjei-Nsiah, Samuel ; Agali, Alhassane ; Bala, Abdullahi ; Chikowo, Regis ; Kaizzi, Kayuki ; Kouressy, Mamoutou ; Makoi, Joachim H.J.R. ; Ouattara, Korodjouma ; Tesfaye, Kindie ; Cassman, Kenneth G. ; Hall, Lindsey ; Kalka, Gogi - \ 2017
    Environmental Science Journal for Teens (2017). - 4 p.
    By the year 2050, the world’s population will need 60% more food than it did in 2005. In sub-Saharan Africa (we’ll call it SSA) (Fig. 1) this problem will be even greater, with the demand for cereals increasing by more than three times as the population rises.
    We collected and calculated farming data for 10 countries in sub-Saharan Africa. This made us realize that countries in SSA must make many large changes to ncrease their yield of cereals (the amount of cereals that are grown on the current farmland each year) to meet this greater demand.
    If countries in SSA are unable to increase cereal yield, there are two options. either farmland areas will have to increase drastically, at the expense of natural land, or SSA will need to buy more cereal from other countries than it does today. This may put more people in these countries at risk of not having enough food to be able to live healthily.
    Maize-legume cropping guide
    Baijukya, F.P. ; Wairegi, L. ; Giller, K.E. ; Zingore, S. ; Chikowo, R. ; Mapfumo, Paul - \ 2016
    CAB International - ISBN 9781780645544 - 83 p.
    Can sub-Saharan Africa feed itself?
    Ittersum, Martin K. Van; Bussel, Lenny G.J. Van; Wolf, Joost ; Grassini, Patricio ; Wart, Justin Van; Guilpart, Nicolas ; Claessens, Lieven ; Groot, Hugo de; Wiebe, Keith ; Mason-d’Croz, Daniel ; Yang, Haishun ; Boogaard, Hendrik ; Oort, Pepijn A.J. van; Loon, Marloes P. van; Saito, Kazuki ; Adimo, Ochieng ; Adjei-Nsiah, Samuel ; Agali, Alhassane ; Bala, Abdullahi ; Chikowo, Regis ; Kaizzi, Kayuki ; Kouressy, Mamoutou ; Makoi, Joachim H.J.R. ; Ouattara, Korodjouma ; Tesfaye, Kindie ; Cassman, Kenneth G. - \ 2016
    Proceedings of the National Academy of Sciences of the United States of America 113 (2016)52. - ISSN 0027-8424 - p. 14964 - 14969.
    Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub-Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase in food demand by 2050 can be met through closing the gap between current farm yield and yield potential on existing cropland. Here, however, we estimate it will not be feasible to meet future SSA cereal demand on existing production area by yield gap closure alone. Our agronomically robust yield gap analysis for 10 countries in SSA using location-specific data and a spatial upscaling approach reveals that, in addition to yield gap closure, other more complex and uncertain components of intensification are also needed, i.e., increasing cropping intensity (the number of crops grown per 12 mo on the same field) and sustainable expansion of irrigated production area. If intensification is not successful and massive cropland land expansion is to be avoided, SSA will depend much more on imports of cereals than it does today.
    Response of Common Bean (Phaseolus vulgaris L.) to Nitrogen and Phosphorus and Rhizobia Inoculation Across Variable Soils in Zimbabwe.
    Chekanai, Vongai ; Chikowo, R. ; Icishahayo, David ; Kanampiu, F.K. ; Giller, K.E. - \ 2016
    - p. 15 - 15.
    Sources of vulnerability to a variable and changing climate among smallholder households in Zimbabwe: A participatory analysis
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2014
    Climate Risk Management 3 (2014). - ISSN 2212-0963 - p. 65 - 78.
    Vulnerability analysis is essential for targeting adaptation options to impacts of climate variability and change, particularly in diverse systems with limited resources such as smallholder farms in sub-Saharan Africa. To investigate the nature and sources of vulnerability of smallholder farmers to climate variability and change, we analysed long term climate data and interviewed farmers individually and in groups in Makoni and Hwedza districts in eastern Zimbabwe. Farmers’ perceptions of changes in climate characteristics matched the recorded data. Total seasonal rainfall has not changed, but variability in the rainfall distribution within seasons has increased. The mean daily minimum temperature increased by 0.2 °C per decade in both Makoni and Hwedza. The mean daily maximum temperature increased by 0.5 °C per decade in Hwedza. The number of days with temperatures >30 °C also increased in Hwedza. Farmers indicated that livestock production was sensitive to drought due to lack of feed, affecting resource-endowed farmers, who own relatively large herds of cattle. Crop production was more sensitive to increased rainfall variability, largely affecting farmers with intermediate resource endowment. Availability of wild fruits and social safety nets were affected directly and indirectly by extreme temperatures and increased rainfall variability, impacting on the livelihoods of resource-constrained farmers. There was no evidence of a simple one-to-one relationship between vulnerability and farmer resource endowment, suggesting that vulnerability to climate variability and change is complex and not simply related to assets. Alongside climate variability and change, farmers were also faced with biophysical and socioeconomic challenges such as lack of fertilizers, and these problems had strong interactions with adaptation options to climate change. Diversifying crops and cultivars, staggering planting date and managing soil fertility were identified as the major adaptation options to stabilize yields against increased rainfall variability. There is need to evaluate the identified adaptation options on farm and with the participation of farmers to provide empirical evidence on the best options for different households.
    N2Africa Phase II 6 months report
    Adjei-Nsiah, S. ; Sangodele, E. ; Wolde-Meskel, E. ; Baijukya, F.P. ; Ebanyat, P. ; Sanginga, J. ; Woomer, P.L. ; Katengwa, S. ; Chikowo, R. ; Leonardo, W.J. ; Boahen, S. ; Phiphira, L. ; Brand, G.J. van den; Giller, K.E. - \ 2014
    N2Africa - 34 p.
    Comparative assessment of maize, finger millet and sorghum for household food security in the face of increasing climatic risk
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2014
    European Journal of Agronomy 55 (2014). - ISSN 1161-0301 - p. 29 - 41.
    southern africa - soil fertility - pearl-millet - sandy soil - zimbabwe - variability - management - adaptation - productivity - agriculture
    Questions as to which crop to grow, where, when and with what management, will be increasingly challenging for farmers in the face of a changing climate. The objective of this study was to evaluate emergence, yield and financial benefits of maize, finger millet and sorghum, planted at different dates and managed with variable soil nutrient inputs in order to develop adaptation options for stabilizing food production and income for smallholder households in the face of climate change and variability. Field experiments with maize, finger millet and sorghum were conducted in farmers’ fields in Makoni and Hwedza districts in eastern Zimbabwe for three seasons: 2009/10, 2010/11 and 2011/12. Three fertilization rates: high (90 kg N ha-1, 26 kg P ha-1, 7 t ha-1 manure), low (35 kg N ha-1, 14 kg P ha-1, 3 t ha-1 manure) and a control (zero fertilization); and three planting dates: early, normal and late, were compared. Crop emergence for the unfertilized finger millet and sorghum was 70% for the fertilized treatments. In contrast, the emergence for maize (a medium-maturity hybrid cultivar, SC635), was >80% regardless of the amount of fertilizer applied. Maize yield was greater than that of finger millet and sorghum, also in the season (2010/11) which had poor rainfall distribution. Maize yielded 5.4 t ha-1 compared with 3.1 t ha-1 for finger millet and 3.3 t ha-1 for sorghum for the early plantings in the 2009/10 rainfall season in Makoni, a site with relatively fertile soils. In the poorer 2010/11 season, early planted maize yielded 2.4 t ha-1, against 1.6 t ha-1 for finger millet and 0.4 t ha-1 for sorghum in Makoni. Similar yield trends were observed on the nutrient-depleted soils in Hwedza, although yields were less than those observed in Makoni. All crops yielded significantly more with increasing rates of fertilization when planting was done early or in what farmers considered the ‘normal window’. Crops planted early or during the normal planting window gave comparable yields that were greater than yields of late-planted crops. Water productivity for each crop planted early or during the normal window increased with increase in the amount of fertilizer applied, but differed between crop type. Maize had the highest water productivity (8.0 kg dry matter mm-1 ha-1) followed by sorghum (4.9 kg mm-1 ha-1) and then finger millet (4.6 kg mm-1 ha-1) when a high fertilizer rate was applied to the early-planted crop. Marginal rates of return for maize production were greater for the high fertilization rate (>50%) than for the low rate (100%) than for the high rate (
    Managing soil fertility to adapt to rainful variability in smallholder cropping systems in Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2013
    Field Crops Research 154 (2013). - ISSN 0378-4290 - p. 211 - 225.
    climate-change - southern africa - sandy soil - corn production - use efficiency - food security - management - maize - farmers - yield
    Adaptation options that address short-term climate variability are likely to lead to short-term benefits and will help to deal with future changes in climate in smallholder cropping systems in Sub-Saharan Africa (SSA). In this study we combined field experimentation and long-term rainfall analyses in Makoni and Hwedza districts in eastern Zimbabwe to evaluate cropping adaptation options to climate variability. Analyses of long-term rainfall data closely supports farmers’ perceptions that the mean annual total rainfall has not changed, but the pattern of rainfall within-season has changed: the number of rainfall days has decreased, and the frequency of dry spells has increased at the critical flowering stage of maize. On-farm experiments were conducted over two cropping seasons, 2009/10 and 2010/11 to assess the effects of planting date, fertilization and cultivar on maize production. Three maize cultivars were sown in each of the early, normal and late planting windows defined by farmers. Each of the nine cultivar-planting date combinations received N, P, K and manure combinations at either zero, low or high fertilization rates. Overall, there were no significant differences in maize development or grain yield among cultivars. Maize grain yield was increased by increasing the amount of nutrients applied. Average yield was 2.5 t ha-1 for the low rate and 5.0 t ha-1 for the high rate on early planted cultivars on relatively fertile soils in Makoni in 2009/10 season. Yields on poorer soils in Hwedza were small, averaging 1.5 t ha-1 for the low rate and 2.5 t ha-1 for the high rate. Maize grain yields for the early and normal planted cultivars were similar for each fertilization rate, suggesting there is a wide planting window for successful establishment of crops in response to increased rainfall variability. Yield reduction of >50% was observed when planting was delayed by 4 weeks (late planting) regardless of the amount of fertilizer applied. Soil nutrient management had an overriding effect on crop production, suggesting that although the quality of within-season rainfall is decreasing, nutrient management is the priority option for adaptation in rain-fed smallholder cropping systems.
    Comparative productivity of maize, finger millet and sorghum for household food security in the face of increasing climatic
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2013
    Participatory action research (PAR) as an entry point for supporting climate change adaptation by smallholder farmers in Africa
    Mapfumo, P. ; Adjei-Nsiah, S. ; Mtambanengwe, F. ; Chikowo, R. ; Giller, K.E. - \ 2013
    Environmental Development 5 (2013). - ISSN 2211-4645 - p. 6 - 22.
    Emerging trends of a changing and increasingly variable climate have introduced new livelihood challenges in rain-fed smallholder agricultural systems that predominate in Sub-Saharan Africa (SSA). The capacity of local farming communities and their institutions to respond to the new and emerging impacts of climate change is often constrained by lack of access to information and improved technologies, as well as poor support mechanisms to promote assimilation of new knowledge. This threatens to heighten vulnerability of the majority of SSA's rural communities who are already facing severe problems of food insecurity and a declining soil resource base. In this paper we use two case studies from Wenchi district in Ghana and Makoni in Zimbabwe to communicate how participatory action research (PAR) methodology, characterised by iterative planning–action–reflection cycles, was coupled with a new concept of field-based farmer learning centres to build adaptive capacity of smallholder farmers to climate change. The study was part of a University of Zimbabwe—led project supported under the Climate Change Adaptation in Africa (CCAA) programme to explore the state of resilience in African smallholder farming. The PAR and learning centre processes enabled communities, local leaders, and extension agents and researchers to establish the, hither to, imperceptible link between poor soil fertility and rising institutional challenges within communities. Institutional conflicts related to land tenure and sharecropping arrangements between migrant farmers and native landowners were addressed in Ghana, while local institutions supporting traditional social safety net mechanisms were revitalized in Zimbabwe. In both cases, it was apparent that farmers faced multiple stresses, at the core of which were poor and declining soil fertility and weakening local institutions. The worsening rainfall distribution and increasing cases of drought are broadening the scope for vulnerability, often driving competing claims and conflicts. PAR was successfully used as an entry point, empowering communities to self-mobilize and self-organize to co-learn and experiment with integrated soil fertility management (ISFM) technologies and other improved farming practices. They realised opportunities for achieving high crop yields and generate surpluses in good years. Strengthening local institutional capacity to revitalise community safety nets proved an essential ingredient for enhancing adaptive capacity of smallholders to climatic shocks. The PAR process was a major driver of effective partnerships among community members, extension, policy makers and researchers, but ensuing success generated a new set of social challenges that could not be addressed within the short timescale of the project. We conclude that PAR was a suitable mechanism for supporting self-organization and co-learning processes among smallholder farmers and their service providers, enabling them to use ISFM technologies and strengthen their local institutions around natural resource management. This revealed the scope for building adaptive capacity of these communities against climate change and variability.
    Managing soil fertility to adapt to climate variability in smallholder systems of Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2012
    Managing soil fertility to adapt to climate variability in smallholder systems of Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2012
    Agroecology-based aggradation-conservation agriculture (ABACO): Targeting innovations to combat soil degradation and food insecurity in semi-arid Africa
    Tittonell, P.A. ; Scopel, E. ; Andrieu, N. ; Posthumus, H. ; Mapfumo, P. ; Corbeels, M. ; Halsema, G.E. van; Lahmar, R. ; Lugandu, S. ; Rakotoarisoa, J. ; Mtambanengwe, F. ; Pound, B. ; Chikowo, R. ; Naudin, K. ; Triomphe, B. ; Mkomwa, S. - \ 2012
    Field Crops Research 132 (2012). - ISSN 0378-4290 - p. 168 - 174.
    heterogeneity - management
    Smallholder farmers in semi-arid Africa are in an increasingly vulnerable position due to the direct and indirect effects of climate change, demographic pressure and resource degradation. Conservation agriculture (CA) is promoted as an alternative to restore soil productivity through increased water and nutrient use efficiencies in these regions. However, adoption of CA is low due to a number of technical reasons, but fundamentally due to the fact that CA has been often promoted as a package, without proper adaptation to local circumstances. Farmers engagement in designing and implementing locally suited CA practices, as part of a long term strategy of soil rehabilitation is the core approach followed by the ABACO initiative, which brings together scientists and practitioners from West, East and Southern Africa coordinated through the African Conservation Tillage Network (www.act-africa.org). ABACO relies on agro-ecologically intensive measures for soil rehabilitation and increased water productivity in semi-arid regions, implemented, tested and disseminated through local co-innovation platforms. Rather than using rigid definitions of CA approaches that might not work in all sites, ABACO proposes to explore best engagement approaches for different sites. Simulation modelling is used as a support of long-term cross scale tradeoffs analysis from field to farms and territories, in order to inform effective policy-making. Preliminary results form the field are used here to illustrate and discuss the principles of ABACO, which may apply as well to regions other than semi-arid Africa.
    Communicating complexity: Integrated assessment of trade-offs concerning soil fertility management within African farming systems to support innovation and development
    Giller, K.E. ; Tittonell, P.A. ; Rufino, M.C. ; Wijk, M.T. van; Zingore, S. ; Mapfumo, P. ; Adjei-Nsiah, S. ; Herrero, M. ; Chikowo, R. ; Corbeels, M. ; Rowe, E.C. ; Baijukya, F.P. ; Mwijage, A. ; Smith, J. ; Yeboah, E. ; Burg, W.J. van der; Sanogo, O. ; Misiko, M. ; Ridder, N. de; Karanja, S. ; Kaizzi, C.K. ; K'ungu, J. ; Mwale, M. ; Nwaga, D. ; Pacini, C. ; Vanlauwe, B. - \ 2011
    Agricultural Systems 104 (2011)2. - ISSN 0308-521X - p. 191 - 203.
    nutrient use efficiencies - crop-livestock systems - western kenya - smallholder farms - land-use - southern mali - cycling efficiencies - exploring diversity - resource-allocation - dynamics
    African farming systems are highly heterogeneous: between agroecological and socioeconomic environments, in the wide variability in farmers’ resource endowments and in farm management. This means that single solutions (or ‘silver bullets’) for improving farm productivity do not exist. Yet to date few approaches to understand constraints and explore options for change have tackled the bewildering complexity of African farming systems. In this paper we describe the Nutrient Use in Animal and Cropping systems – Efficiencies and Scales (NUANCES) framework. NUANCES offers a structured approach to unravel and understand the complexity of African farming to identify what we term ‘best-fit’ technologies – technologies targeted to specific types of farmers and to specific niches within their farms. The NUANCES framework is not ‘just another computer model’! We combine the tools of systems analysis and experimentation, detailed field observations and surveys, incorporate expert knowledge (local knowledge and results of research), generate databases, and apply simulation models to analyse performance of farms, and the impacts of introducing new technologies. We have analysed and described complexity of farming systems, their external drivers and some of the mechanisms that result in (in)efficient use of scarce resources. Studying sites across sub-Saharan Africa has provided insights in the trajectories of change in farming systems in response to population growth, economic conditions and climate variability (cycles of drier and wetter years) and climate change. In regions where human population is dense and land scarce, farm typologies have proven useful to target technologies between farmers of different production objectives and resource endowment (notably in terms of land, labour and capacity for investment). In such regions we could categorise types of fields on the basis of their responsiveness to soil improving technologies along soil fertility gradients, relying on local indicators to differentiate those that may be managed through ‘maintenance fertilization’ from fields that are highly-responsive to fertilizers and fields that require rehabilitation before yields can improved. Where human population pressure on the land is less intense, farm and field types are harder to discern, without clear patterns. Nutrient cycling through livestock is in principle not efficient for increasing food production due to increased nutrient losses, but is attractive for farmers due to the multiple functions of livestock. We identified trade-offs between income generation, soil conservation and community agreements through optimising concurrent objectives at farm and village levels. These examples show that future analyses must focus at farm and farming system level and not at the level of individual fields to achieve appropriate targeting of technologies – both between locations and between farms at any given location. The approach for integrated assessment described here can be used ex ante to explore the potential of best-fit technologies and the ways they can be best combined at farm level. The dynamic and integrated nature of the framework allows the impact of changes in external drivers such as climate change or development policy to be analysed. Fundamental questions for integrated analysis relate to the site-specific knowledge and the simplification of processes required to integrate and move from one level to the next. Keywords: Crop–livestock systems; Soil fertility; Smallholders; Farm types; Simulation modelling
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