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 !