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