Evaluating yield gaps in cassava production systems in Zambia · Evaluating yield gaps in cassava...

25
A member of CGIAR consortium www.iita.org Evaluating yield gaps in cassava production systems in Zambia Nhamo NHAMO (PhD) Cassava Agronomist The World Congress on Root an Tuber Crops, 18-22 January, 2016 Nanning, Guangxi, China

Transcript of Evaluating yield gaps in cassava production systems in Zambia · Evaluating yield gaps in cassava...

A member of CGIAR consortium www.iita.org

Evaluating yield gaps in cassava

production systems in Zambia

Nhamo NHAMO (PhD)

Cassava Agronomist

The World Congress on Root an Tuber Crops,

18-22 January, 2016

Nanning, Guangxi, China

A member of CGIAR consortium www.iita.org

Outline

1. Yield gaps in cassava systems

2. Observations from cassava production

systems in Zambia

3. Improved Cassava production practices

4. Focusing on the gains to close gaps

5. Conclusions

2

A member of CGIAR consortium www.iita.org

Cassava is food

Cassava

processing

for food:

Peeling and

pounding for

household

food

3

A member of CGIAR consortium www.iita.org

Yield gaps…1

Yield gap is the difference between the

farmers’ average crop yield and the

biologically and climatically attainable yield

for a particular area

• Yield determining factors (radiation & temp)

• Yield limiting factors (soil water & nutrition)

Overall cassava production is linked

to the size and nature of gaps in the

system4

A member of CGIAR consortium www.iita.org

5Lobell et al. 2009; Nhamo et al. 2014

The process:

1. Simulation modeling

2. On-station trials

3. Diagnostic surveys

4. On-farm research

5. Farmer driven research

An illustration of yield

gaps at different levels

A member of CGIAR consortium www.iita.org

Farmer vs Research plots

6Groundnut

OkraCassavaSweetpotato

Cassava and maize intercrop

(i) (i i)

A member of CGIAR consortium www.iita.org

Why work on yield gaps?

• Adequately describe

cassava production systems

• Analyse yields in relation to

production factors

• Design interventions for

improved cassava systems

7

Understanding farmers’ practices

A member of CGIAR consortium www.iita.org

Current practices

8

Cropping patterns

District

All

Serenje Samfya Mansa Kasama Kaoma

Mono cropping (%) 71 51 42 50 65 56

Mixed cropping (%) 29 49 58 50 35 44Weeding method

Only manual 98 100 100 99 100 99

Only herbicides 0 0 0 0 0 0

Manual+herbicides 0 0 0 0 0 0

Other 0 0 0 0 0 0

Types of fertilisers

No fertiliser 92 100 79 95 100 93

Organic fertiliser 6 0 1 0 0 1

Chemical fertiliser 0 0 0 0 0 0

Combination of

organic and

chemical fertilisers 1 0 3 4 0 2

Mixed cropping

is common

practise

Low to no

external

agrochemical

inputs

Source: IITA farmers surveys

Manual

weeding

methods

A member of CGIAR consortium www.iita.org

Cassava intercropping

9

Cropping patterns

Camp

AllKapyata Bahati Chisunka

Mono cropping (%) 40 20 40 33

Mixed cropping (%) 60 80 60 67

Maize (%) 20 20 20 20Millet (%) 0 0 0 0

Cotton (%) 0 0 0 0

Groundnuts (%) 30 20 30 27Cowpea (%) 0 0 0 0

Sweet potatoes (%) 10 40 10 20Potato (%) 0 0 0 0

Vegetables (%) 0 0 0 0

A member of CGIAR consortium www.iita.org

Cassava lessons

• 1960s +i. Cassava was introduced for poor

farmers to avert persistent droughts

ii. Limited support from the government

»e.g. extension training does not include

cassava production practices

• 2000 +i. Recognition of importance is beginning

to increase

ii. Value chain and Markets not devoloped

10

A member of CGIAR consortium www.iita.org

Project Areas

11

Southern Africa

A member of CGIAR consortium www.iita.org

Soils characteristics

12

Site

pH

(CaCl2)

P

ppm

Ca

ppm

Mg

ppm

K

ppm

OC

%

N

%

CEC

Cmol+kg

Kaoma 4.5 5 180 10 19 0.08 0.04 1.87

Kasama 4.1 4 60 20 137 0.65 0.03 7.17

Mansa 4.2 6 100 40 116 0.20 0.02 6.31

Serenje 4.2 23 70 40 36 0.37 0.02 1.89

• Acidity linked to highly weathered

soils and rainfall

• Low soil organic matter and CEC

• 2/4 sites deficient in K

• P deficiency at all sites except Serenje

A member of CGIAR consortium www.iita.org

Rainfall patterns

13

0

50

100

150

200

250

Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14

Rain

fall (

mm

)

Time (Months)

Total rainfall = 1020 mm

• Rain falls for about 6 months per year

• Large storms often short duration

• Uneven distribution during the season –

midseason droughts

Total rainfall

is probably

not a major

bottleneck

A member of CGIAR consortium www.iita.org

Temperature extremes

14

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

MinTemp oC

MaxTempoC

High probability of minimum temperatures

below 12 oC between May and August

Loss of leaves due to

dry and cold weather

A member of CGIAR consortium www.iita.org

Sources of Yield Gains

• Moving from blanket to site-specificity

• Effective use of fertilizer in combination with

other technologies

• Weed management practices that explore

synergies with other technologies

• Future role of improved varieties which have

characteristics that address more than one

constraint

• Yield targeting under improved nutrient, water

and weed management15

A member of CGIAR consortium www.iita.org

Focusing on the gains to

close gaps

Agronomy research

1. Cassava intensification options

2. Weather/Climate patterns

3. Extension messages on management

– Crop response to improved management

• Fertilizer inputs

• Weed management

• Time of planting

• Planting population

16

A member of CGIAR consortium www.iita.org

Yields response to

management

17

Means and 95% C.I. of R_Yld for W_man

1 2 3 4 50

5

10

15

20

R_

Yld

W_man

Means and 95% C.I. of R_Yld for Popn

1 20

4

8

12

16

R_

Yld

Popn

SED 1.7863

1=Clean weeding 2=Farmer’s practice

3. Delayed first weeding 4=No weeding

5=Manual and chemical

Means and 95% C.I. of Rt_yld for fert

F1 F2 F30

10

20

30

Rt_

yld

fert

F1 = No fertilizer F2 = 40N 40P 40K

F3 = 120N 80P 80K

SED 1.2416

P1 = 10000 ha-1 P2 = 20000 ha-1

SED 3.2442

Means and 95% C.I. of R_Yld for Time

1 2 30

8

16

24

R_Y

ld

Time

Planting times

1. December 2. January 3. February

Significant yield loss

due to delayed

planting, no weeding

and higher plant

populations.

Significant yield

gains due fertilizer

inputs and related

management.

Timing important for

climate extremes,

weeding and plant

populations for

resource

management.

A member of CGIAR consortium www.iita.org

Cassava Root Yield gains

18

Practice Yield gain

(t/ha)

Relative

gain (%)

Fertilizer 7-18 35%

Weed Management 7-17 63%

Timing of planting 7-10 83%

Plant population 3-5 48%

A member of CGIAR consortium www.iita.org

Re-designing Cassava

production system

19

Cutting trees

Burning organics

Crop mixes

Rainfall

patterns;

TemperatureSoil quality;

organic

matter loss; Crop productivity

goes down

A member of CGIAR consortium www.iita.org

Conclusions

Options for intensification

• Fertilizer application supports high

yields in cassava systems

• Intensification requires efficient

utilization of fertility input for

sustainability

20

A member of CGIAR consortium www.iita.org

Weed management in cassava

• Large differences exist between

weeded and unweeded plots (4-17

t/ha)

• High planting density did not reduce

weed biomass in cassava plots

• Manual and chemical weed

management practices need to be

evaluated

21

A member of CGIAR consortium www.iita.org

Timing and plant populations

• Cassava root yields responded to

time of planting and planting

populations.

• Management of the growing

season is important for cassava

bulking especially in Zambia

22

A member of CGIAR consortium www.iita.org

Next steps…

• Data on crop response important for:

• developing decision support tools for

farmers and extension personnel

• extension messages for specific

environments

• Intensification options and stepwise

adoption of technologies

• Farm budgets for large scale farmers

• Markets and market linkages

23

A member of CGIAR consortium www.iita.org

Acknowledgements

• The African Development Bank (AfDB)

• IITA Team and Partners

• Farmers, women and youth

24

25

Thank You!