Farmers in sub-Saharan Africa (SSA) often depend on nutrient-poor soils, e.g., Ferralsols and Nitosols. Intensive farming and absence of fallows has led to further decline in soil fertility, resulting in low yields and under- as well as malnourishment. Our research, education and information activities in SSA all are connected to the improvement of smallholder farming systems, by increasing soil fertility to reach higher and sustainable yields. Considering that most smallholders are subsistence farmers, and that their livelihood is totally reliant on farming activities, our activities also touch on socio-economic aspects of farming related to livelihoods. We collaborate with scientists from international research centers such as CIAT-TSBF and ICRAF within and outside our disciplines, which yields a T-shaped competence base (illustrated in Figure 1), both in our projects and, hopefully, in the minds of the individual researchers.
Figure 1. Our aim is to obtain a deep competence within one area and a general competence within additional areas. This can be reached through collaboration across disciplines and is illustrated above as a T-shaped figure, indicating a T-shaped competence, with soil fertility as the main competence area.
Our objectives are in line with the Swedish Government’s ‘politics for global development’ (PGU) in identified global challenges as climate change and environmental impact. Our long-term ambition is to expand and consolidate the present research and educational activities in SSA, e.g., by providing infrastructure for SLU researchers.
Figure 2. ICRAF (World Agroforestry Center) where TSFB is based, highlighted areas where field trials are located and Sörgården, SLUs house in Nairobi.
Our main projects in SSA:
1. Carbon dynamics in arable land in sub-Saharan Africa (2005-2007, O. Andrén)
A Sida/FORMAS funded project where soil carbon dynamics were analyzed based on available soil, climate and crop data and the five-parameter ICBM model. The project was undertaken at TSBF-CIAT in Nairobi, Kenya. TSBF is part of the CGIAR institute CIAT, and is responsible for research concerning soil- biology and fertility.
2. Soil C management in Kenyan smallholder land use systems – C sequestration, GHG emissions and socio-ecological dynamics (2006-2008, K. Röing de Nowina)
A Sida funded project, where carbon stocks and greenhouse gas emissions were quantified for two Kenyan eco-regions and assessed in relation to Integrated Soil Fertility Management (ISFM) practices. Part 1 quantified C stocks under the current ISFM land use systems and identified socio-ecological dynamics within different eco-regions and social strata. Part 2 considered the C sequestration potential in these systems by a field experimental phase where C build-up and N2O emissions were evaluated. The field work was located in Embu (Central) and Kisumu (West).
3. Black carbon in soil – for sequestration and reduction of nutrient losses (2006-ongoing, O. Andrén)
This project was based in Sweden (funded by FORMAS), but long-term field trials located in Embu, (Central Kenya) and in Kisumu (Western Kenya) were started in 2006. The main question addressed by the Kenyan studies is if long-term soil fertility can be improved by biochar addition. In Kenya, several factors have been studied after addition of charcoal to the soils, some of them being soil physical aspects as water holding capacity and soil biodiversity. Higher and more consistent crop yields have been recorded (Andrén et al., in prep.) and in spring 2011 five new field trials will be started in Kenya, in cooperation with KARI (Kenya Agriculture Research Institute) and other local organizations.
4. On-farm evaluation of soil fertility improvement in cereal-legume crop rotations with in situ produced organic matter amendments in Nigeria and Kenya (2007-2009, Kristina Röing de Nowina)
A Sida/FORMAS funded project where organic material was produced in situ as soil fertility amendments in cereal-legume crop rotations and evaluated on-farm, together with smallholder farmers. The study included an on-station field trial in Nigeria, in collaboration with scientists from the international Institute of Tropical Agriculture (IITA) and researcher-managed trials on-farm in Kenya.
5. Alleviation of low soil fertility and Striga hermonthica constraints to crop productivity by integration of dual purpose legumes in maize-based systems in smallholder farms in Western Kenya (2010-2012, Kristina Röing de Nowina)
A Sida/FORMAS funded project aiming at increasing yield and sustainable production of cereal-legume rotations for small-holder farmers in Western Kenya by developing an integrated approach to Striga management and soil fertility. Striga infestation and soil fertility status will thus be characterized and monitored in target areas as case studies on farmers´ fields and the effect of Striga yield losses will be evaluated through socio-economic surveys at household level. Multi-locational field trials will be established in different agro-ecological zones to assess possible technologies for Striga reduction that contribute to soil fertility. A soybean-based intervention in a push-pull system that causes suicidal germination of Striga seed will be tested for reduction of Striga emergence and improvement of soil fertility status and cereal productivity. The study will take place in two districts in W Kenya, with low to severe infestation of Striga, and with different soil fertility status, enabling a cross comparison.
6. Evaluating organic matter dynamics, soybean production, value-addition and Striga weed suppression in Integrated Soil Fertility Management systems - towards improved productivity, sustainability, and livelihoods of smallholder farmers in Kenya and Uganda (2011-2012, Kristina Röing de Nowina )
This project is funded by the Swedish Ministry of Foreign Affairs (UD) where the main theme is diversified and sustainable cropping systems and efficient use of resources and soil fertility. This project will focus on Integrated Soil Fertility Management (ISFM) components to improve rural livelihoods in Kenya and Uganda. The project synthesizes current activities at SLU (Röing, Andrén, Dahlin, Lagerlöf, Öborn etc) and TSBF-CIAT, and links to on-going BMGF, AGRA and UD-SLU-projects. This project provides knowledge and networks for farmers, scientists and NGO’s on (soil) organic matter, plant nutrition, soil fertility and cropping systems under varying agro-ecological and climatic conditions, fitting with the overall theme.
We supervise Swedish students (MFS, i.e., minor field studies; MSc., M Agr, lic. etc.) which gives us further opportunities for collaboration with other researchers at institutes (CGIAR, KARI) as well as universities.
Literature
Published and in prep.
Andrén, O., Röing de Nowina, K. and more (in prep). Application of biochar to soils in Western and Central Kenya – effect on crop yields and nutrient uptake during 8 growing seasons. Journal not selected.
Andrén, O., Kihara, J., Bationo, A., Vanlauwe, B. and Kätterer, T. 2007. Soil climate and decomposer activity in sub-Saharan Africa, estimated from standard weather station data – used in soil carbon balance calculations. Ambio 36:379-386.
Andrén, O. and Kätterer, T. 2008. Agriculture Systems. In: Sven Erik Jørgensen and Brian D. Fath (Editor-in-Chief), Ecosystems. Vol. [1] of Encyclopedia of Ecology, 5 vols. pp. [96-101] Oxford: Elsevier.
Andrén, O., Kätterer, T., Juston, J. and Waswa, B. In press. Soil carbon dynamics as a result of climate, cropping systems and soil type – rapid calculations using ICBM and agricultural field trial data from sub-Saharan Africa. In: Waswa, B and Bationo A. Eds. Proceedings of the International Meeting: Innovations as Key to the Green Revolution in Africa: Exploring the Scientific Facts, Arusha, Tanzania, 17- 21 Sept 2007.
Juston, J., Andrén, O., Kätterer, T. and Jansson, P-E. 2010. Uncertainty analyses for calibrating a soil carbon balance model to agricultural field trial data in Sweden and Kenya. Ecological Modeling 221:1880-1888.
Student reports (MFS, BSc, MSc etc.):
Alvum-Toll, K., Karlsson, T. and Ström, H. 2011. Biochar as soil amendment – A comparison between plant production from three regions in Kenya
Andersson, J. and Halvarsson, M. 2011. The economic consequences of Striga hermonthica in maize production in Western Kenya
Bertholds, C. and Olsson, K. 2006. Soil physical properties and erosion risks at smallholder farms in Embu in Kenya
El Khosht, F. and Larsson, M. 2009. Effects of charcoal on soil physical properties – case studies from Kenya
Fransson, J. and Lindgren, J. 2009. Soil fertility and field management in Central and Southeast Kenya
Rosén, S. 2008. Soil properties in relation to farmers’ perception of soil fertility in different provinces of Kenya
Rånlund, E. 2007. Environmental impact of agriculture in Kenya perceived by smallholder farmers – case studies from Embu and Kisumu
Wanjau Wambui, F. 2010. The influence of charcoal application on soil fauna and fertility in Central and Western Kenya
Contact information for Olof Andrén can be found at http://www.oandren.com/
email: prof@oandren.com