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Striga asiatica: a driving-force for dissemination of conservation agriculture systems based on Stylosanthes guianensis
in Madagascar
Dr. Olivier Husson
Michellon, R.; Naudin, K.; Letourmy, P.; Enjalric, F.;
Penot, E., Séguy, L.
Moussa, N.; Randrianjafizanaka, M.T.;
Andrianaivo, A.P.
Raveloarijoana, N.
Rakotondramanana
Striga in the world
Parasite of cereals
50 million hectares, 300 million people
Jeopardizes food security (Ejeta, 2007)
S. asiatica S. hermontica
Elusive wide-scale effective control
Striga in Madagascar
South–West & Middle West
S. asiatica
Striga asiatica
700 - 1,100 meters a.m.s.l.
1,000-1,500 mm/year
6 months dry season
Striga in Madagascar
“Medium” scale agriculture
Compacted soil, +/- degraded
Rice//maize
Field abandonment – Village migration
Objective
Can we propose practical CA systems that effectively control striga?
YES WE CAN !!!
Striga : driving–force for CA dissemination
Material and methods (1/3)
From 2002/03 TAFA/CIRAD Test of 4 CA systems
Rice//maize+ tillage
2 to 4 replicates200 m²
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
Material and methods (1/3)
1. Rice + Stylosanthes // maize+ Stylo.
Material and methods (1/3)
2. Rice // maize+B. ruziziensis + C. cajan
Material and methods (1/3)
3. Rice // maize + cowpea
Material and methods (1/3)4. Rice + Arachis sp // maize + Arachis
Arachis pintoï and Arachis repens
Material and methods (2/3)
From 2004/05, extension programmesFAFIALA, ANAE, SD-MadMonitoring / Data base
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 depth0-12 cm and 24-36 cm from maize row
Results (1/3)
Cropping system
Maize +
Average number of
striga seeds
(0-12 cm)
Average number of parasite striga plants (0-12 and
24-36cm)
(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).
Systems with Stylosanthes or Arachis control striga
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
Results (3/3)
Rapid dissemination of systems with Stylosanthes
Results (3/3)
Possibility to re-introduce rice and maize in the cropping systems with CA identified as a major factor of CA adoption (Sorreze, 2010)
Fastest rate of CA dissemination in Madagascar
Discussion
Why DMC/CA controls striga (hypothesis)
Temperature control/conditioning
Triggering “suicidal germination”
N + C inputs
Favourable conditions for striga parasites
Discussion
Stylosanthes based cropping systemsEasy to implement
Robust and resilient
Small scale, low input to mechanized, commercial agriculture
Easy to learn (progressive)
Flexible
Efficient Production
Weed control
60-70 % of CA systems in the area
Conclusions
Farmers adopt CA/DMC systems as it is the only possibility they have to effectively control striga
Some CA/DMC systems actually control striga
CA/DMC systems based on Stylosanthes are practical, easy to implement and very efficient
Major constraint driving force for CA
Website: http://agroecologie.cirad.fr
Thanks for your attention !
http://agroecologie.cirad.fr/librairie-virtuelle
Thanks for your attention !
Conservation agriculture :
100% of the winners did play !