Download - Cassava: What do we know about the crop?
CassavaWhat do we know about the crop?
Stefan Hauser, Root & Tuber Crop Systems Agronomist
Total NigeriaSoil management nutrient supply 81 55Soil management intercropping 29 19Soil management tillage 12 8Soil management green manure 6 4Soil management mulch 5 5Soil management alley cropping 12 8Crop management 30 22Pest & disease management 6 1Climate 1 1
182 123
What has been published?
What is IITA working on in the Agronomy and Natural Resource Management domain?
RTB – Root & Tuber Agronomy:Effect of compost lime and fertilizer on leaf an root yields of 3 cassava varieties.Effect of planting sick size and position and fertilizer application on germination and root yield of two cassava varieties.Effect of fallow type, biomass management and fertilizer on cassava root yield in Cameroon .
SARD SC:Root yield response of 9 cassava varieties to fertilizer and leaf harvest .Root yield response of 6 cassava varieties to fertilizer and different leaf harvest intensities
CRP Maize:Compatibility of maize and cassava varieties for intercropping and effects of fertilizer and leaf harvest in DR Congo
These are the small ones . . . . .
Sustainable Weed Management in Cassava Systems:
Agronomic measures to reduce weed pressure, effects of reduced weeding and weeding methodand mechanical weeding options
African Cassava Agronomy Initiativedemand-driven development of agronomy interventions, focusing on specific needs of development and private sector partners.
ACAI (African Cassava Agronomy Initiative):
Linked to input supply and fertilizer industry• Site-specific fertilizer recommendations• New fertilizer blends optimized for cassava production in
major cassava-growing areas
General for all cassava growers• Best planting practices (tillage, density, fertilizer application)• Optimal intercropping practices (focus on maize in Nigeria)
Linked to output markets• More continuous supply to processing factories by staggering
planting and harvesting• Increased starch yields (higher DM and starch content)
Cassava agronomy technology options: 6 use cases
Why now on-farm cassava agronomy trials?
!YIELD
In cassava we may well look at a yield gap equivalent to 90% of the yield potential.80 Mg ha-1 fresh roots are often quoted as a potential but on single plant basis 120 Mg ha-1 are possible.
Currently the focus in research is still on germplasm improvement.
Certainly important but will not solve production problems in the long term
Yield of improved vs local cassava varieties
CNN reported 50 t/ha by Zimbabwean farmers in Kwara State, Nigeria
EdoBayelsa
Cross RiverAkwa Ibom
EbonyiEnugu
AnambraImo
RiversDeltaAbia
Yield across States (t/ha)0 5 1510 20 25 30 35
Improved varieties
Local varieties
Some of the reasons are:•Bad misconceptions of crop requirements (cassava),•Low level of mechanization,•Soil degradation, unsuitable tillage systems •Lack of reliable recommendations on fertilizer use, •Unavailability of suitable herbicides, •Insufficient knowledge on the crops’ responses to intercrops•Insufficient knowledge on profitable input use (economics)
•Low level of intensification, •Small scale production,
Source df SS P>F SS P>F SS P>FLoc 13 971721 <0.0001 35920 <0.0001 5871 <0.0001Fert 1 1448 0.0963 359 0.0001 0.7 0.8178Loc*Fert 13 21722 <0.0001 1740 <0.0001 112 0.0229Clone 42 198689 <0.0001 6107 <0.0001 3576 <0.0001Fert*Clone 42 11123 0.9964 674 0.9537 870 0.0027
R-square 0.6886 0.6378 0.6838CV 31.83 26.84 10.29
Root number Fresh yield (t/ha) Dry matter (%)
Fertilizer response, 14 locations, 200 kg/ha NPK
0
10
20
30
40
50
60
70
80
90
100
4(2)
1425
82/0
0058
91/0
2324
92/0
057
92/0
067
92/0
325
92/0
326
92B/
0006
1
92B/
0006
8
94/0
026
94/0
039
94/0
561
95/0
166
95/0
289
95/0
379
96/0
523
96/0
603
96/1
089A
96/1
565
96/1
569
96/1
632
96/1
642
97/0
162
97/0
211
97/2
205
97/3
200
97/4
763
97/4
769
97/4
779
98/0
002
98/0
505
98/0
510
98/0
581
98/2
101
98/2
226
99/2
123
99/3
073
99/6
012
M98
/002
8
M98
/004
0
M98
/006
8
TME4
19
TMS3
0572
Perc
ent c
hang
e in
Fre
sh ro
ot y
ield
18.8271
17.8915
17.4
17.6
17.8
18
18.2
18.4
18.6
18.8
19
F NF
Fres
h yi
eld
(t/h
a)
LSD = 0.57
Percent change: 5.23
0.0
Significant interactions indicating differential response of varieties to location and fertilizer
18.8
17.9
111
222
333
444
1836
5472
95
190
285
380
0
50
100
150
200
250
300
350
400
450
5 10 15 20 25 30 35 40 45
Root DM yield (Mg ha-1)
Nut
rient
upt
ake
(kg
ha-1
)
NPK
Current potential yield equivalent to 80-90 Mg ha-1 fresh roots
Which nutrients and how much is required?
What went wrong?What goes wrong?
The actual heterogeneity of a cassava population (plot or treatment) is rather high in both, above ground mass and tuberised root
mass.
Individual cassava plants separated into leaf bearing branches stem and roots, Kiyaka, Nov. 2011
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 10 20 30 40 50 60 70 80 90 100
Percent plants
Rel
ativ
e co
ntrib
utio
n to
yie
ld
Cultivar Zizila, 12 MAP, leaves not harvested, Mvuazi, Bas Congo
Relative contribution to the yield of individual plants of a cassava variety in DR Congo planted at 1 x 1m (10000 ha-1).
87.7% of root mass deemed suitable, 11.56 Mg ha-1 fresh roots
Variety Sadisa, 12 MAP, Kiyaka, Bandundu, DR Congo
Root fresh mass = 1.26 stem & leaf fresh massr2 = 0.8625, N=192
0
2000
4000
6000
8000
10000
12000
0 1000 2000 3000 4000 5000 6000 7000 8000
Stem and leaf fresh mass
Roo
t fre
sh m
ass
Sadisa, 12 MAP, 22.6 Mg ha-1
Root fresh mass = 1.127 stem & leaf fresh massr2 = 0.78, N = 215
0
2000
4000
6000
8000
10000
12000
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Stem & leaf mass (g)
Roo
t fre
sh m
ass
(g)
TME 419, 12 MAP, 32.1 Mg ha-1
Secondary tuberous roots of various sizes
Roots like pearls on a string
Not to talk about the shape and size
Data on single factor effects and interactions on weed abundance and
biomass and cassava yields
0
5
10
15
20
25
Variety Site System Tillage Fertilizer
Cas
sava
fres
h ro
ot y
ield
(Mg
ha-1
)
TME 419
IntercropIdo
Moniya
TMS 30572
Monocrop Ridged
Flat
Fertilizer
Nil
p<0.0013 p<0.0163p<0.0001p<0.0001
p<0.0001
Cassava root yields 1st season
Useful cassava fresh root yield by factor in a first season planted cassava crop.
0
5
10
15
20
25
Use
ful c
assa
va f
resh
root
yie
ld (M
g ha
-1)
Monocrop
Ido
Moniya
IntercropTMS 30572
TME 419 Ridged
FlatNil
Fertilizer
p<0.0001
p=0.001p<0.0001
p<0.0001
p<0.0013
Useful cassava fresh root yield by factor in a second season planted cassava crop.
System Site Variety Fertilizer Tillage
Cassava root yields 1st season
0 20 40 60 80 100 120 140 160 180 2000
5
10
15
20
25
30
35
Moniya 2 Ido 2 Moniya 1Ido 1
Cas
sava
fres
h ro
ot y
ield
(Mg
/ ha)
mean 15.0
mean 18.1
114 plots, equiv. to 59.4% larger than the National average (12.5 Mg/ha)
173 plots, equiv. to 90.1% larger than the National average (12.5 Mg/ha)
Yield distribution in 1st and 2nd season at Moniya and Ido
0
10000
20000
30000
40000
50000
60000
70000
0 500 1000 1500 2000 2500 3000
Use
ful c
assa
va fr
esh
root
yie
ld (K
g ha
-1)
Sequential plot number in descending order of yield
1st season
2nd season
Double National average25000 Kg ha-1
National average12500 Kg ha-1
Mean 13380 Kg ha-1
Mean 16150 Kg ha-1
Yield distribution in 1st and 2nd
season at 15 sites in Nigeria
?
The IITA Agronomy Laboratory at Mampu,DR Congo
26www.iita.orgA member of CGIAR consortium
Clearly - there is no shortage of open questions in cassava agronomy and crop husbandry in SSA.
Conclusion
Thank you