th2_integrated and locally adapted striga asiatica control
DESCRIPTION
3rd Africa Rice Congress Theme 2: Intensification and diversification Mini symposium: Rice pests: evidence of effects and management Author: AndrianaivoTRANSCRIPT
INTEGRATED AND LOCALLY ADAPTED STRIGA ASIATICA
CONTROL: Combining a Zero-tillage Rice–Maize
Cover-Crop Rotation System with Resistant Rice Varieties
Alain Paul Andrianaivo
(SRiD-FoFiFa, Antananarivo, Madagascar)
Roger Michellon
(SCRiD-Cirad, Antsirabe, Madagascar)
Jonne Rodenburg
(AfricaRice , Dar es Salaam, Tanzania)
Meva Tahiry Randrianjafizanaka
(Univ. Tulear ,Madagascar)
• Common weed in the mid-west of the Vakinankaratra region (800-1000 a.s.l.)
• Cropping systems: Rice//maize
• Serious yield losses
Striga asiatica (L.) Kuntze
Objective
Integrated• Striga control
• Soil conservation management
Hypotheses
• Combining zero-tillage with intercropping will- protecting the soil - improving the organic matter content- reduce Striga infestation rates
• Striga resistant rice varieties should enhance Striga suppression
• Stylosanthes has a suppressive effect on Striga
Material and methods
three seasons (2011-2014)
Split-Split plot design (6 rep.) 4 cropping systems(S1-S4)
3 rice varieties (V1-V3) 1 maize locally variety
• Treatments and experimental set-up
• Site Selection: Ivory
Material and methods
• S1: Rice//Maize + tillage + Crop residue removal • S2. Rice // Maize + Cowpea + Mucuna
• S 3. Rice // Maize + Vigna umbellata
• S4. Rice + Stylosanthes // Maize+ Stylo.
V1: B 22. , Striga susceptible
V2: Nerica 9. Striga moderately resistant
V3: Nerica 4. Striga resistant
System
Tillage and residue
management
Phase
Season 1 (2011-2012)
Season 3 (2013-2014)
Season 2 (2012-2013)
System 1
Tillage, No residues
P1 Rice Maize
P2 Maize Rice
System 2
Zero-tillage + Residues
P1 Rice Maize + cowpea + mucuna
P2 Maize + cowpea + mucuna Rice
System 3
P1 Rice Maize + Vigna umbellata
P2 Maize + V. umbellata Rice
System 4
P1 Rice + Stylosanthes(year 1)
Maize + Stylosanthes (year 2)
P2 Maize + Stylosanthes (year 1) + supplementary Stylosanthes residues
Rice in Stylosanthes residues of year 11
Table 1. Cropping systems plan for season 1 to season 3.
Material and methods
ResultsTable 2. Striga numbers (10 m-2) in rice at harvest
Season SystemRice variety
MeanB22 NERICA-9 NERICA-4
2011/20121
S1: Rice//Maize 38.9 2.1 0.2
4.3
S2: Rice//Maize cowpea + mucuna 6.9 1.7 1.3 2.7
S3: Rice//Maize V. umbellata 6.3 2.5 0.6 2.4
S4: Rice + Stylosanthes//maize + Stylosanthes 9.1 1.6 0.9 2.7
Mean 11.3 A2 2.0 B 0.7 B
2012/20133
S1: Rice//Maize 159.4 a4 37.4 ab 0.3 cd 65.7 x5
S2: Rice//Maize cowpea + mucuna 38.8 ab 22.4 ab 2.6 cd 21.3 x
S3: Rice//Maize V. umbellata 14.9 bc 17.5 ab 0.4 cd 11.0 x
S4: Rice + Stylosanthes//maize + Stylosanthes 3.9 bcd 1.9 cd 0.00 d 1.9 y
Mean 54.3 A 19.8 B 0.8 C 25.0
1 In the 2011-2012 cropping season, phase 1, S1 till S3 are all rice-only.
2 Values in the same row followed by different letters (A-C) are significantly different (P<0.05).
3 Results on rice in season 2012-2013 are derived from plots that were preceded by maize or maize and cover crops in the 2011-2012 season (earlier referred to as phase 2).
4 Values followed by different letters (a-d) are significantly different (P<0.05).
5 Values in one column followed by different letters (x or y) are significantly different (P<0.05).
Table 3. Striga numbers (10 m-2) in maize in season 2 near harvest time, following different cropping systems and with different rice varieties in the preceding 2011/2012 season.
Season
System
Rice variety in preceding season
Mean
B22
NERICA-9
NERICA-4
2012/2013
S1: Rice//Maize 306.8 a1 100.2 a 19.1 ab 142.0 x2
S2: Rice//Maize cowpea + mucuna 35.5 a 38.5 a 43.8 ab 39.3 y
57.8 y
S3: Rice//Maize V. umbellata 90.5 a 63.3 a 19.6 a
S4: Rice + Stylosanthes//maize + Stylosanthes 0.0 b 0.0 b 0.0 b 0.0 z
Mean 108.2 A3 50.5 AB 20.6 B
1 Values followed by different letters (a-d) are significantly different (P<0.05).
2 Values in ‘Mean’ column followed by different letters (x or y) are significantly different (P<0.05).
3 Values in the ‘Mean’ row followed by different letters (A-C) are significantly different (P<0.05).
Results
Maize//NERICA9 Maize//B22 Maize//NERICA4
carry-over effect of resistance in Maize//Rice
Table 4. Rice yields (t ha-1) following different cropping systems and rice varieties
Season System Rice variety Mean
B22 NERICA-9 NERICA-4
2011/20121
S1: Rice//Maize
1.8 1.9 2.1 1.9 S2: Rice//Maize cowpea + mucuna
S3: Rice//Maize V. umbellata
S4: Rice + Stylosanthes//maize + Stylosanthes 1.9 1.7 1.7 1.73
Mean 1.8 1.8 1.9
2012/2013 S1: Rice//Maize 1.8 c2 2.3 bc 2.2 bc 2.1 y3
S2: Rice//Maize cowpea + mucuna 2.9 ab 3.2 a 3.3 a
3.2 x
S3: Rice//Maize V. umbellata 2.5 abc 1.9 c 2.2 bc 2.2 y
S4: Rice + Stylosanthes//Maize + Stylosanthes 0.74 d 0.5 d 0.5 d 0.6 z
Mean 2.0 A5 2.0 A 2.1 A
1 In the 2011-2012 cropping season, phase 1, S1 till S3 are all rice-only; therefore these systems are combined in the analyses, for comparison with rice - Stylosanthes. No
significant yield differences were observed this season.
2 Values followed by different letters (a-d) are significantly different (P<0.05).
3 Values in the ‘Mean’ column, followed by different letters (x-z) are significantly different (P<0.05).
4 This system should be evaluated in the third year following all of the three stages: 1. Rice with Stylosanthes (year 1) followed by 2. Maize with Stylosanthes (year 2),
concluded by 3. Rice sown in the slashed residues of the Stylosanthes.
5 Values in the same row followed by different letters (A-C) are significantly different (P<0.05).
Results
Conclusions
• Striga densities are reduced by S2, S3 and S4. Particulary
with Vigna umbellata and Stylosanthes guianensis.
• With respect to rice yields, the best system, is S2 :(Rice//Maize
+cowpea+mucuna
• For subsistence farmers in central Madagascar, that have to
deal with soils that are both highly infested by Striga asiatica
and highly vulnerable to degradation, a system of rice rotation
with a maize – legume intercrop following zero-tillage, without
removing crop residues, is likely to represent an attractive
alternative to the current practice
Merci de votre aimable attention !
Acknowledgements
CGIAR /GRISPCirad