Presentation from the WCCA 2011 conference in Brisbane, Australia.

1. Striga asiatica:
a driving-force for dissemination of
conservation agriculture systems
based on Stylosanthes guianensis
in Madagascar
Dr. Olivier Husson

2. Michellon, R.; Naudin, K.;
Letourmy, P.; Enjalric, F.;
Penot, E., Séguy, L.
Moussa, N.;
Randrianjafizanaka, M.T.;
Andrianaivo, A.P.
Raveloarijoana, N.
Rakotondramanana

3. Striga in the world
Parasite of cereals
50 million hectares, 300 million people
Jeopardizes food security (Ejeta, 2007)
Elusive wide-scale effective control
S. asiatica S. hermontica

4. Striga in Madagascar
Striga asiatica
South–West & Middle West
700 - 1,100 meters a.m.s.l.
1,000-1,500 mm/year
6 months dry season
S. asiatica

5. Striga in Madagascar
Compacted soil, +/- degraded
“Medium” scale agriculture
Rice//maize
Field abandonment – Village migration

6. Objective
Can we propose practical CA systems
that effectively control striga?
YES WE CAN !!!
Striga :
driving–force
for CA
dissemination

7. Material and methods (1/3)
From 2002/03
TAFA/CIRAD
Test of 4 CA
systems
Rice//maize
+ tillage
2 to 4 replicates
200 m²

8. Material and methods (1/3)
DMC systems : Direct-Seeding, Mulch-
based Cropping systems
3 principles of CA
+ high biomass
production by
multifunctional
cover crops
Muskwari sorghum

9. Material and methods (1/3)
1. Rice + Stylosanthes // maize+ Stylo.

10. Material and methods (1/3)
2. Rice // maize+B. ruziziensis + C. cajan

11. Material and methods (1/3)
3. Rice // maize + cowpea

12. Material and methods (1/3)
4. Rice + Arachis sp // maize + Arachis
Arachis pintoï and Arachis repens

13. Material and methods (2/3)
From 2004/05, extension programmes
FAFIALA, ANAE, SD-Mad
Monitoring / Data base

14. Material and methods (3/3)
2009/10 specific study on striga
control: striga seeds and plants
Ø 12 cm cylinder x 4 rep.
0-10 cm and 10-20 cm depth
0-12 cm and 24-36 cm from maize row

15. Results (1/3)
Systems with Stylosanthes or Arachis
control striga
Average Average number
Cropping system number of of parasite striga
striga plants (0-12 and
Maize + seeds 24-36cm)
(0-12 cm)
(CA) Arachis pintoï 1.0 a 0.0 a
(CA) Stylosanthes 1.5 a 1.0 a
(CA) Brachiaria+Cajanus 4.5 ab 3.5 bc
(CA) Cowpea 15.5 c 3.0 bc
(CT) Tillage 8.6 bc 8.4 c
Mean values in each column followed by the same letter(s) are not different in
Fisher pairwise comparison (least significant difference, p-value= 0.05).

16. Results (2/3)
Systems with Stylosanthes produce more
and more regularly than other systems
4275 kg/ha
1805 kg/ha
Recommended fertilization: 5t/ha manure + 50 N - 30 P – 40 K

17. Results (3/3)
Rapid dissemination of systems with
Stylosanthes

18. Results (3/3)
Fastest rate of CA dissemination in
Madagascar
Possibility to re-introduce rice and
maize in the cropping systems with CA
identified as a major factor of CA
adoption (Sorreze, 2010)

19. Discussion
Why DMC/CA controls striga
(hypothesis)
Temperature control/conditioning
N + C inputs
Triggering “suicidal germination”
Favourable conditions for
striga parasites

20. Discussion
Stylosanthes based cropping systems
Easy to implement
Easy to learn (progressive)
Robust and resilient
Flexible
Small scale, low input to
mechanized, commercial agriculture
Efficient Production
Weed control
60-70 % of CA systems in the area

21. Conclusions
Some CA/DMC systems actually
control striga
CA/DMC systems based on
Stylosanthes are practical, easy to
implement and very efficient
Farmers adopt CA/DMC systems as it
is the only possibility they have to
effectively control striga
Major constraint  driving force for CA

22. Thanks for your attention !
Website: http://agroecologie.cirad.fr
http://agroecologie.cirad.fr/librairie-virtuelle

23. Thanks for your attention !
Conservation agriculture :
100% of the winners did play !