Striga asiatica: a driving-force for dissemination of CA systems based on Stylosanthes guianensis in Madagascar. Olivier Husson
Striga asiatica:a driving-force for dissemination of conservation agriculture systemsbased 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) Elusive wide-scale effective control S. asiatica S. hermontica
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
Striga in Madagascar Compacted soil, +/- degraded “Medium” scale agriculture 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 replicates 200 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 programmes FAFIALA, ANAE, SD-Mad Monitoring / 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 depth 0-12 cm and 24-36 cm from maize row
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).
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) 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)
Discussion Why DMC/CA controls striga (hypothesis) Temperature control/conditioning N + C inputs Triggering “suicidal germination” Favourable conditions for striga parasites
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
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
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