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Browsing by Author "Corbeels, Marc"

Now showing 1 - 11 of 11
  • Comparative performance of conservation agriculture and current smallholder farming practices in semi-arid Zimbabwe
    Baudron, Frederic; Tittonell, Pablo; Corbeels, Marc; Letourmy, P.; Giller, Ken (Elsevier B.V., 2012)
    Conservation agriculture is promoted in sub-Saharan Africa as a means to improve water use efficiency in an region with variable or poorly distributed rainfall. However, other environmental and social factors may contribute to the success or failure of implementation and practice. The purpose of this study was to compare on-farm conservation agriculture trials of cotton and sorghum with production practices currently in place. Two experiments at multiple locations were executed. The first involved an unfertilized cotton-sorghum rotation (three consecutive seasons), while the second examined cotton production with fertilizer provided on credit (two consecutive seasons). Mulches were produced on site to further emulate conditions present for farmers of the Mid-Zambezi valley. Farmers' perceptions of the technologies involved were also studied. CA was found to have no effect on cotton yields during the first two seasons, which received average or above average rainfall, but was found to be detrimental to yields during a third season of decreased rainfall. Additionally, greater run-off was found in on-farm CA trials in coarser soils than fine-textured soils. Farmers perceived that plowing was necessary to avoid soil crusting and compaction in drier years while CA was beneficial during wetter seasons. The authors site poor mulch coverage as a factor in this result and recommend legume intercropping as part of the solution.
  • Conservation agriculture and smallholder farming in Africa: The heretics' view
    Giller, Ken; Witter, Ernst; Corbeels, Marc; Tittonell, Pablo (Amsterdam, Netherlands: Elsevier B.V., 2009)
    This paper critically analyzes the claims of successful conservation agriculture adoption (CA). CA is said to increase yields, to reduce labor requirements, improve soil fertility and reduce erosion. Yet, according to the authors the empirical evidence is not clear and consistent on many of those points. In sub-Saharan Africa the available evidence suggests virtually no uptake of CA. The authors conclude with a need for critical assessment of the ecological and socio-economic conditions for which CA is best suited.
  • Conservation agriculture: A reality check for adopting CA in sub-Saharan Africa and QAToCA - a qualitative expert assessment tool for CA adoption
    Corbeels, Marc (2011)
    Many socio-economic, political, biological, and market issues influence the adoption of conservation agriculture practices in sub-Saharan Africa. The following presentation reviews QAToCA, a qualitative expert assessment tool that can be used to predict the likelihood of adoption and scalability of those innovations.
  • Cotton expansion and biodiversity loss in African savannahs, opportunities and challenges for conservation agriculture: A review paper based on two case studies
    Baudron, Frederic; Corbeels, Marc; Monicat, F.; Giller, Ken (Amsterdam, Netherlands: Springer Netherlands, 2009)
    This article reviews the potential for conservation agriculture to develop productive and environment-friendly cropping systems using the experiences of two African landscapes. Conservation agriculture can potentially benefit biodiversity and turn agriculture from a threat into an opportunity for conservation. The authors also raise a number of challenges inhibiting the growth of conservation agriculture by resource-poor farmers.
  • Failing to yield? Ploughs, Conservation Agriculture and the problem of agricultural intensification: An example from the Zambezi Valley, Zimbabwe
    Baudron, Frédéric; Andersson, Jens A.; Corbeels, Marc; Giller, Ken E. (Routledge, 2012)
    Two agricultural intensification policies currently have a foothold in Southern Africa: intensification by plough-based, animal integrated practices and intensification by conservation agricultural practices including natural resource management. The former ideology originated from colonialism while the latter is currently promoted by nongovernmental organizations and development agencies. However, analysis on farmer knowledge relating to both of these practices reveals a predisposition towards extensification, or the farming on more land and using more resources to increase yields, instead of intensification. Other factors include limited cash, elevated risks, fluctuations in labor availability, and high input prices. Interestingly, the authors cite reliance on purely technical fixes, the disregarding of local or placed-based knowledge, and ultimately the lack of innovation on the side of researchers, development agencies, and policy-makers as the true reasons why Africa farmers are "failing to yield."
  • The farm-level economics of conservation agriculture for resource-poor farmers
    Pannell, D. J.; Llewellyn, R. S.; Corbeels, Marc (2014)
    This article utilizes economics to examine constraints to the uptake of Conservation Agriculture (CA) in South Asia and sub-Saharan Africa. The authors develop a conceptual framework to anchor a discussion of the role of farm-level economics in CA adoption. This conceptual framework serves as a lens through which the authors examine literature on CA adoption, and as a basis for a quantitative model to explore the economic performance of CA. The literature review examines studies on specific components of CA, as well as studies of the CA package as a whole. The majority of publications on the CA package, as well as on the rotation and minimum tillage components, demonstrate that farmers would benefit from adoption. Despite this, adoption remains low. Several possible explanations of non-adoption are offered. The article also describes a quantitative model, based on a case study in northern Zimbabwe, that further explores farm-level economics of CA. Findings from this analysis demonstrate that CA is more attractive when farmers have larger framers, longer time horizons, fenced land, or less uncertainty about CA benefits. The model reinforces the authors’ argument that the farm-level economics of CA varies widely based on factors specific to each farm and to each region.
  • Farmers' knowledge of soil fertility and local management strategies in Tigray, Ethiopia
    Corbeels, Marc; Shiferaw, A.; Haile, M. (International Institute for Environment and Development, 2000)
    Declining soil fertility is a major constraint on crop production in the semi-arid highlands of Tigray, Northern Ethiopia. In order to design more appropriate research and development programmes geared to improving integrated nutrient management practices, researchers need to understand farmers' knowledge and perceptions of soil fertility. This working paper presents the results of a participatory survey designed to characterise and analyse local knowledge about soil fertility and soil fertility management practices. The survey was carried out in two villages in Tigray.
  • A fourth principle is required to define Conservation Agriculture in sub-Saharan Africa: The appropriate use of fertilizer to enhance crop productivity
    Vanlauwe, Bernard; Giller, Ken; Corbeels, Marc; Gerard, B.; Nolte, C. (2014)
    Conservation agriculture (CA) is often promoted as a key to intensifying agricultural production in sub-Saharan Africa. Despite significant efforts to promote CA, however, adoption remains limited in this region. This article contends that CA requires a fourth principle of appropriate fertilizer use to complement the already accepted principles of minimal tillage, maintaining a soil cover, and crop diversification. In regions where CA was widely adopted, fertilizer application was an essential part of agricultural systems, and a key to the success of CA. Appropriate fertilizer application is necessary for CA to be a successful alternative to conventional production in sub-Saharan Africa.
  • A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions
    Rusinamhodzi, L.; Corbeels, Marc; van Wijk, M. T.; Rufino, M. C.; Nyamangara, J.; Giller, Ken (Springer, 2011)
    Conservation agriculture is often encouraged for use in rain-fed maize systems in Southern Africa. The purpose of this meta-analysis is to identify the factors on maize yield in these conditions. Twenty-six studies lasting over 5 years were analyzed. Results indicate much variability and dependence on multiple influences on yield, such as rainfall, mulch cover, soil texture, nitrogen inputs, and climate. Some results include: mulch cover in high rainfall areas leads to lower yields, well-drained soils are necessary in order to see improved yields over time, and higher nitrogen inputs are necessary to achieve higher yields. The authors conclude that conservation agriculture and its related techniques must be adapted to specific biophysical conditions in order to have a beneficial impact on maize yields.
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    Tailoring Conservation Agriculture to Local Contexts and Conditions of Smallholder Farmers in Africa
    Corbeels, Marc; Triomphe, B.; Tittonell, Pablo; Affholder, F.; Lahmar, R.; Scopel, E.; Alary, V.; Jourdain, D. (2010)
    This presentation provides an overview of the need for and challenges to adapting Conservation Agriculture practices to local conditions and social context in Sub-Saharan Africa. Major constraints addressed are start-up costs coupled with longer term yield increases, poor access to markets, and the need for capacity building prior to implementation.
  • Understanding the impact and adoption of conservation agriculture in Africa: A multi-scale analysis
    Corbeels, Marc; de Graaff, Jan; Ndah, Tim Hycenth; Penota, Eric; Baudron, Frederic; Naudin, Krishna; Andrieua, Nadine; Chirata, Guillaume; Schuler, Johannes; Nyagumboe, Isaiah; Rusinamhodzi, Leonard; Traoref, Karim; Mzobag, Hamisi Dulla; Adolwah, Ivan Solomon (2014)
    Conservation agriculture (CA) has been lauded as a means for smallholder farmers in sub-Saharan Africa to increase yields through improving soil fertility and water retention. CA’s principles of minimum tillage, cover cropping, and crop rotations have been promoted in sub-Saharan Africa by many organizations, and significant resources have been invested in research and development initiatives devoted to CA. Despite this, adoption of CA in sub-Saharan Africa remains low. This article seeks to understand why this is true, and to come to a better comprehension of why, where, and for whom CA works best. To do so, the authors analyze several case studies of CA adoption projects in sub-Saharan Africa across four scales: field, farm, village, and region. Yield simulations are used to analyze the field scale, however, the authors point out that yield benefits are multifaceted and may not be well represented by simulations. Analysis of the farm and village scales find that both trade-offs and synergies exist between CA and livestock production systems, varying greatly by the farming context. A constraint identified at the regional level is the absence of input and output markets that are conducive to the adoption of CA. Although projects may provide inputs, farmers are left without access to inputs after the project ends, decreasing the likelihood that they will maintain CA practices. The authors indicate that, in order for CA adoption to move forward, initiatives must reach beyond agronomic research and seek to adapt CA to local conditions.