Improved cassava maize intercropping systems for sustainable cassava and maize production in Nigeria

1. Improved cassava-maize intercropping
systems for sustainable cassava and maize
production in Nigeria
PhD Research project under the Intercropping use case in the ACAI project.
Swiss Federal Institute of Technology, Zurich, Switzerland (ETH Zurich).
Charles Chigemezu, Nwokoro

2. Cassava-maize intercropping in Nigeria
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• 68% of cassava intercropped
• 75% intercropped by maize
• 43% of farmers apply fertilizer to the
maize intercrop,
• 94% of farmers commercialize at least
half of the maize produce. Main objective
is faster access to food and income.
However, yields from both crops are poor in the intercropping system,
Due to poor – bad agronomic (management) practices among other things.
Hence, the need to improve the agronomic potentials of the system in Nigeria.

3. Research hypotheses
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N:P:K
N:P:K +
increased (40,000
ha-1) maize
density
Capture more light,
reduce soil temp.
and retain
moisture.
Improve growths,
developments and
yields of both
crops in the
intercropping
system.
Increased
crop canopy
Affects fresh
cassava root
qualities (HCN,
starch content
and rots).
90:20:40
Vs.
75:20:90

4. 3. To investigate the effect of application of two rates of N:P:K (90:20:40 and 75:20:90) on
cassava starch and HCN contents.
Objectives of the study
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1. To determine the effect of N:P:K (0, 90:20:40 and 75:20:90) application on cassava and
maize growths, developments and yield performances in the intercropping system.
N:P:K
2. To determine the effect of fertilization and maize population densities (20,000 vs
40,000) on light interception, soil moisture and temperature in the intercropping system.

5. Experimental design
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Combination of levels of studies factors (2017 trials):
1. Cassava, Hi maize; NoF = D
2. Cassava, Lo maize; NoF = LM
3. Cassava, Hi maize, Fert.1. = F1
4. Cassava, Lo maize, Fert.1. = LMF
5. Cassava, Hi maize, Fert.2. = CF2
6. Cassava, Lo maize, Fert.2. = CLMF
Levels of studied factors:
N:P:K inorganic fertilizer
0,
90:20:40 kg ha-1 Fertilizer1 (F1); basal N:P:K + 2 splits of Urea,
75:20:40 kg ha-1 Fertilizer2 (F2); basal TSP + 3 splits of Urea and
MoP.
Maize (SAMMAZ 35 (yellow) /38 (white)) density
20,000 plants ha-1 maize; Low maize (LM); 1 m x 0.50 m,
40,000 plants ha-1 maize; High maize (D); 1 m x 0.25 m.
Cassava – TME 419, 12,500 plants ha-1

6. Experimental design and trial locations in Nigeria
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Combination of levels of studies factors (2018 trials):
1. Cassava, Hi maize; NoF = D
2. Cassava, Lo maize; NoF = LM
3. Cassava, Hi maize, Fert.1. = F1
4. Cassava, Lo maize, Fert.1. = LMF
5. Cassava, Hi maize, Fert.2. = CF2
6. Cassava, Lo maize, Fert.2. = CLMF
7. Maize sole, Hi Fert.1. = MSF1
8. Maize sole, Lo Fert.1. = MSLMF
9. Cassava sole, Fert.1. = SCF1
10.Cassava sole, Fert.2. = SCF2
CIM-3 2017 MLTs CIM-4 2017 MLTs
Layout; Multilocational trial
Fert.1
12.5 k
Cass.
Fert.1
12.5 k
Cass.,
20 k
Maize
Fert.2
12.5 k
Cass.,
20 k
Maize.
12.5 k
Cass.,
40 k
Maize,
Lo
Maize
12.5 k
Cass.,
Fert.2
12.5 k
Cass.,
40 k
Maize.
Fert.2
12.5 k
Cass.,
40 k
Maize.
Fert.1
12.5 k
Cass.,
20 k
Maize.
Fert.1
12.5 k
Cass.,
20 k
Maize
.
12.5 k
Cass.,
40 k
Maize,
12.5 k
Cass.,
20 k
Maize
Fert.2
12.5 k
Cass.,
40 k
Maize.
Dens.
12.5 k
Cass.,
40 k
maize.
Fert.2
12.5 k
Cass.,
20 k
Maize.
Fert.1
12.5 k
Cass.,
20 k
Maize.
12.5 k
Cass,
20 k
Maize
,
Fert.1
12.5 k
Cass.,
20 k
Maize.
Fert.2
12.5 k
Cass.,
40 k
Maize.
Fert.1
12.5 k
Cass.,
40 k
Maize.
Fert.1
12.5 k
Cass.,
20 k
Maize.
Fert.2
12.5 k
Cass.,
20 k
Maize.
12.5 k
Cass.,
40 k
Maize,
12.5 k
Cass.,
20 k
Maize.
Fert.2
12.5 k
Cass.,
40 k
Maize.
CIM-5 2017 and 2018 RMTs
Layout; Replicated researcher managed trial

7. Trial environments and sites
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Environments identified based on clustering exercise using GIS information
(climate, soil and vegetation) across the partners’ target area of intervention area for the IC use case.
Soil and climate characteristics of selected experimental sites over 40 (1950 – 2000) years
MLTs environments/sites Replicated trials sites
Agro-ecology State Soil type (USDA) Mean annual temp. (o C) Rainfall (mm yr-1)
1 Humid forest Anambra Fluvisols 26.1 – 27.8 1,561 – 1,821
2 Humid forest Anambra Histosols 26.1 – 27.8 1,341 – 1,561
3 Humid forest Cross River Phaeozems 24.4 – 26.1 2,258 – 2,899
4 Derived savannah Cross River Spodosols 21.5 – 22.9 1,561 – 1,821
5 Derived savannah Benue Nitisols 22.9 – 24.4 1,561 – 1,821
6 Derived savannah Benue Cambisols 22.9 – 24.4 1,136 – 1,341

8. Overview of measurements/field observations
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Light interception, soil temperature and moisture:
• PAR sensors connected to EM50 data loggers,
• Soil moisture probes connected to EM50 data loggers,
• Soil temperature – iButton.
Cassava and maize growth, development and yield observations:
• Height (cm), Leaf count, leaf dimensions (maize), canopy
dimensions (cassava), days to anthesis and silking (maize alone),
• Fresh root and cob yields t ha-1 of cassava and maize, respectively.
Fresh cassava root starch contents (%) insitu:
• Underwater weight method >> calculate SG = Wo / Wo – (Wu + BC)
• CSC (%) = (SG – 1.00906) / 0.004845 (Sunzikaw, 2008).

9. Overview of results – maize height (cm), LAI 8 WAP
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IC = Intercropped,
MS = maize sole,
F1 = 90:20:40 N:P:K,
F2 = 75:20:90 N:P:K,
H = 40,000 plants ha-1 maize,
L = 20,000 plants ha-1 maize.
F1*High maize (40,000
plants ha-1) statistically
significantly (p < 0.05)
improved maize growth
and developments in
both sites, however,
response was location
(soil) dependent. Sandy
soils was less
responsive as was
envisaged.

10. Overview of results – maize tasseling and silking
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0
10
20
30
40
50
60
70
Daystotasselingandsilking
Treatments
Tass
Silk
0
10
20
30
40
50
60
70
80
Daystotasselingandsilking
Treatments
Tasselling
Silking
Effect of N:P:K and environment (soil) on maize tasseling and silking
Igbariam (clayey) vs. Omogho (sandy soil)>>>>>
N:P:K application
enhanced
flowering in
maize. Sandy
soils was less
responsive with
no silk
production on
most control
plots.

11. www.iita.org | www.cgiar.org | www.acai-project.org
Overview of results – maize cob yield t ha-1
2017 2018
Higher N application increased height, LAI and
subsequently fresh cob yields (> 3 t ha-1) in all
locations relative to lower N rates in both (2016
and 2017) years.
Order of significance: F1H = F2H > NoFLo

12. Overview of results – cassava growth (2018 trails)
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Application of N:P:K increased leaf production, stem height and canopy
dimension (data not shown) of cassava. However, there was more
competition for resources (especially light) in higher maize density plots
evidenced by taller stands of cassava and maize.

13. Overview of results – fresh root yield (t ha-1) – 2017 trials
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P-Value
Density 0.663
Fertilizer 1.00e-06
Soil 9.72e-10
Dens*Fert. 0.655
Frt1: 90:20:40 N:P:K,
Frt2: 75:20:90 N:P:K,
NoF: 0:0:0 N:P:K.
There was no
statistically
significant effect of
higher maize density
on fresh cassava
root yield in all
locations studied.
However, 75:20:90
N:P:K gave root yield
> 20 t ha-1, which
was not different
statistically from
90:20:40 treatment
plots.

14. Overview of results – Light interception, soil moisture and
temperature.
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R1CF2 Port 1 Port 2 Port 3
662 records 10HS Soil Moisture 10HS Soil Moisture QSO-S PAR Photon Flux
Measurement Time m³/m³ VWC m³/m³ VWC PAR µmol/m²s
9/28/2017 5:00 PM 0.245 0.290 9.2
9/28/2017 5:30 PM 0.246 0.255 14.6
9/28/2017 6:00 PM 0.248 0.255 12.8
9/28/2017 6:30 PM 0.251 0.255 1.8
9/28/2017 7:00 PM 0.252 0.255 0.0
9/28/2017 7:30 PM 0.254 0.255 0.0
9/28/2017 8:00 PM 0.255 0.255 0.0
9/28/2017 8:30 PM 0.256 0.255 0.0
9/28/2017 9:00 PM 0.257 0.255 0.0
9/28/2017 9:30 PM 0.257 0.255 0.0
9/28/2017 10:00 PM 0.257 0.256 0.0
9/28/2017 10:30 PM 0.258 0.256 0.0
9/28/2017 11:00 PM 0.258 0.256 0.0
9/28/2017 11:30 PM 0.259 0.257 0.0
9/29/2017 12:00 AM 0.259 0.257 0.0
9/29/2017 12:30 AM 0.260 0.258 0.0
9/29/2017 1:00 AM 0.260 0.259 0.0
9/29/2017 1:30 AM 0.261 0.259 0.0
9/29/2017 2:00 AM 0.261 0.260 0.0
9/29/2017 2:30 AM 0.261 0.261 0.0
9/29/2017 3:00 AM 0.261 0.261 0.0
9/29/2017 3:30 AM 0.261 0.261 0.0
9/29/2017 4:00 AM 0.261 0.262 0.0
9/29/2017 4:30 AM 0.262 0.262 0.0
9/29/2017 5:00 AM 0.262 0.263 0.0
9/29/2017 5:30 AM 0.262 0.263 0.0
9/29/2017 6:00 AM 0.262 0.264 0.0
9/29/2017 6:30 AM 0.262 0.264 0.0
9/29/2017 7:00 AM 0.262 0.264 29.3
9/29/2017 7:30 AM 0.262 0.265 62.3
9/29/2017 8:00 AM 0.263 0.265 82.4
9/29/2017 8:30 AM 0.264 0.266 217.9

15. Overview of results – cassava starch content (%) 1st year
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Frt1: 90:20:40 N:P:K,
Frt2: 75:20:90 N:P:K,
NoF: 0:0:0 N:P:K.
There was no
established effect of
N:P:K on fresh root
starch content (%)
across locations.
However, there was a
result (in Igbariam) of
Frt1. fertilization regime
giving a mean value
(40.3 %) at the edge of
statistical significance
(p-value = 0.06) at 5%
level of probability.
The inconsistency of
the result pattern could
be attributed to
management – late
planting.
IgbariamIkomOmogho

16. Preliminary conclusions
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1. Cassava appears unaffected by intensification in maize.
2. Response to higher planting density of maize is not site-specific (for the
selected maize variety)
3. The height of maize (without fertilizer application) at tasselling can be used
as indicator for the response to fertilizer (evidence from multilocational
trials).
4. The maize fertilizer regime (F1) is preferred in all situations (over F2) for a
better cob yield.
5. The cassava fertilization regime (F2) is preferable so far for higher fresh
cassava root yield.
6. Most likely N:P:K affected cassava root starch, 2018 research data will
provide more insight.

17. THANK
YOU!