1. Swedish University of Agricultural Sciences
www.slu.se
Evaluating OM dynamics, soybean
production, value-addition and
Striga weed suppression in
ISFM systems –
towards improved productivity, sustainability, and
livelihoods of smallholder farmers
in Kenya and Uganda
Kristina Röing de Nowina
Bernard Vanlauwe
SLU/CIAT-TSBF/IITA

2. Swedish University of Agricultural Sciences
www.slu.se
Drawing: Miriam Larsson

3. Swedish University of Agricultural Sciences
www.slu.se
c. 20% of maize area in Africa infested
Estimated loss in harvest in Africa worth 7 Billion USD/yr

4. Swedish University of Agricultural Sciences
www.slu.se
Justification
• Soybean improves soil fertility and farmer livelihoods
through its N fixation capacity, organic inputs, nutritional
benefits, and marketing potential. Soybean can also
reduce the Striga weed seed bank through suicidal Striga
germination.
• Improving soil C stocks through organic matter
management enhances soil fertility and crop productivity.
Options for soil fertility amendment also include organic
resources of varying biochemical quality and bio-char,
where C is added to the soil in a more stable form.

5. Swedish University of Agricultural Sciences
www.slu.se
Map of Kenya.
Arrows indicate areas of project activities

6. Swedish University of Agricultural Sciences
www.slu.se
0
1000
2000
3000
4000
5000
6000
7000
No N, no
charcoal
Charcoal Fertilizer Charcoal,
fertilizer
Maizeyieald(kgha-1)
The science;
Biochar - effects on soil and yields
Terra Preta soils in the
Amazonas are highly fertile
soils with high content of inert,
”black” carbon.
How could this apply to Africa?
Maize grown in plots in C Kenya with biochar and fertilizer (left),
control (center) and biochar only (right).
Field trials in Western and Central
Kenya since 2006;
• Yields monitored
• Soil and plant properties analysed
• Organic matter decomposition/modelling studied
• DNA technologies for assessment of soil microfauna
used.
Sustained good yields where
biochar has been applied.

7. Swedish University of Agricultural Sciences
www.slu.se
The science;
Soil fertility and Striga
Striga hermonthica, a parasitic
weed, is a major problem in
Africa.
Can soybean (Glycine max) be
used to combat Striga while
improving soil fertility?
The project is based on
experiences from AATF, KARI,
ICIPE and others. Activities were
undertaken in collaboration with
CIAT-TSBF/IITA.
Includes field trials and
participatory approaches in
Western Kenya to study
consequences of Striga. Soybean
varieties will be tested for effect on
Striga reduction and soil fertility
improvement.
BSc and MSc students have been
involved.
Maize field in W Kenya with severe infestation of Striga
hermonthica.

8. Swedish University of Agricultural Sciences
www.slu.se
Relationship between farm
management, soil health and Striga
• Farm management assessed
– in 300+ farms in 6 districts (Vihiga, Siaya, Bondo, Teso, Kisumu, Busia)
• KAP study (Knowledge, attitude and practices)
– In 100+ farms in 3 districs
• Field trials:
– effect of improved maize varieties and fertilizer on maize
productivity and Striga germination
20 trials LR 2011 in 2 districts (Siaya, Bondo)
30 trials; SR 2011; 6 districts (Vihiga, Siaya, Bondo, Kisumu, Teso, Busia)
30 trials; LR 2012 6 districts (Vihiga, Siaya, Bondo, Kisumu, Teso, Busia)
• Field trials:
– effect of different varieties of soyabean on striga weed suppression
30 trials SR 2011 in 4 districts SR 2011(Vihiga, Siaya, Teso, Busia)
30 trials LR 2011 in 4 districts SR 2011(Vihiga, Siaya, Teso, Busia)

9. Swedish University of Agricultural Sciences
www.slu.se
Partners and links
• CIAT-TSBF/IITA (Bernard Vanlauwe)
– AfNet (Saidou Koala)
• Links to
– Moi University, Kenya
– Nairobi University, Kenya
– AGRA
– N2Africa
– AfSIS

10. Swedish University of Agricultural Sciences
www.slu.se
Project Outcomes
• Potential increased collaboration with IITA
– Kristina Röing de Nowina Coordinator of Proposal Development at
IITA as of January 1, 2013.
• Sida/VR-funded project 2013-2015 on biochar in
relation to biomass, soil and energy
– Collaboration between IITA and SLU
• Discussions on an Africa Ministerial Meeting on
Integrated Soil Fertility Management
– IITA involved in leading this initiative and initial plans have been
discussed with AfNet, AGRA, IFAD, FAO, AU and AfDB.

11. Swedish University of Agricultural Sciences
www.slu.se
Thanks to all farmers, staff,
partners, collaborators and
students!