Closing the maize yield gap in Ethiopia:
National analysis
Michiel van Dijk and Tom Morley
Imagine meeting 27 April, 2017
Contributions: Assefa Admassie, Katrien Descheemaeker, Martin van Ittersum, Roel Jongeneel, Marloes van
Loon, Pytrik Reidsma, Joao Nunes Vieira da Silva, Kindie Tesfaye
Main findings
 Technology gap (57%) makes up the largest component of
the yield gap.
 Economic constraints (30%) make up the second largest
component of the yield gap
● It is not profitable for farmers to use more fertilizer given
current yield response and input and output prices.
● Using improved seeds substantially increases yield.
 Technical efficiency makes up 10% of the total yield gap.
● Extension services have a positive (but small) effect on
technical efficiency.
2
Policy messages

Expanding extension services to all farms will increase maize
yield.

Improved farm management practices are required to close the
technical efficiency yield gap.

Profitability analysis suggest that input and output prices are such
that farmers do not have an incentive to expand production
beyond the current level.

Stimulating the use of improved seeds has the potential to
increase maize yield (but there might be economic constraints).

Closing the (technology) yield gap requires the diffusion of
transformative technologies, policies and practices (e.g.
precision farming).

3
Objectives
 Integrate economic and agronomic approaches to
assess yield gaps
 Use the approach to analyse the constraints to
maize yield growth in Ethiopia at the national
level
 Provide policy recommendations
4
Conceptual framework
5
Five different yield levels to benchmark
farmer performance
Yield (tons/ha)
Biophysical maximum production
level (climate, CO2, water)
w.l. potential
yield
Best-practice + no economic
constraints on inputs (on farm
demonstrations)
Feasible yield
Economic yield
Technical
efficient yield
Actual yield
Yield
gap
Best-practice + profitmaximizing
Best-practice
Observed yield at the plot
6
Policies to close the yield gap(s)
Main causes
Yield (tons/ha)
Potential yield
Technology
Yield gap
Feasible yield
Economic yield
Yield
gap
Economic
Yield gap
• Agricultural innovation
• Diffusion of transformative
system and broader
technologies, policies and
institutional, technological,
practices
economic and social factors
• Transaction and
transportation costs.
• Investment in rural roads
• Domestic production of
fertilizer
Allocative
Yield gap
• Credit & insurance
• Knowledge and financial
constraints, risk issues and • Expand agro-dealer networks
• Support market information
information asymmetries
• Land tenure systems
• Smart input subsidies
Technical
efficiency
yield gap
• Suboptimal crop
management caused by
knowledge, skills and
information gaps.
Technical
efficient yield
Policies
• Improve extension services
• Stimulate knowledge transfer
from best practice to average
farmers
Actual yield
7
Yield gap measurement and estimation
Household survey,
Climate and soil
information
Stochastic frontier
analysis
Literature study
Global Yield
Gap Atlas
Best practice
Yield response function
Actual
yield
Technical
efficient
yield
Economic
yield
Feasible
yield
Water-limited
Potential
yield
Yield gap decomposition
8
Data: Household survey (LSMS-ISA)
Source: World Bank
9
Data: Global Yield Gap Atlas
Source: www.yieldgap.org
10
Actual yield (Ya), water-limited yield (Yw) and other
statistics by zone
ZONE
Yield
(kg/ha)
w.l. Potential
yield (kg/ha)
Fertilizer
(%)
Nitrogen
(kg/ha)
Area
(ha)
Improved
seeds (%)
Extension
(%)
Number
AMHARA
1,727
11,607
47
91.9
0.13
34
52
587
850
6,361
59
51.2
0.13
14
43
162
OROMIYA
1,730
13,042
31
69.6
0.17
21
30
705
SNNP
1,860
12,362
35
64.7
0.18
27
26
574
SOMALI
1,031
10,571
2
7.8
0.32
0
2
90
TIGRAY
1,381
10,556
38
56.3
0.1
3
54
216
OTHER
1,827
12,709
4
13.2
0.23
4
5
318
TOTAL
1,685
11,888
35
71.3
0.16
21
34
2,562
HARARI
11
Technical efficient yield (Yte): Extension
services matter
Plots with extension services have on average
~10 pp higher technical efficiency
12
Economic yield: Not profitable for farmers
to use more nitrogen
ZONE
YR
VCR
Fertilizer
(%)
Nitrogen
(kg/ha)
AMHARA
6.2
0.61
47
91.9
HARARI
5.6
0.55
59
51.2
OROMIYA
10.0
0.99
31
69.6
SNNP
11.8
1.17
35
64.7
TIGRAY
6.3
0.63
38
56.3
TOTAL
8.4
0.83
39
72.2
World Bank (2010) YR: 4.1-12.1 kg maize/kg N
Minten et al. (2013) YR: 11-12 kg maize/kg N
 Yield response (YR) to
nitrogen use ~8.4 kg
maize/kg N
 Value cost ratio (VCR)< 1.
 But excludes 65% of
farmers with N =0!
 Highly depends on relative
price information!
13
Feasible yield (Yf): what if
inputs would be for free?
Assumptions
•
•
•
•
50% more seeds
•
All farmers use
improved seeds
•
All farmers use manure
50% more labour
400 kg N/ha
All farmers use animal
traction
14
Comparison of yield levels by zone
15
Decomposition of the yield gap
16
By how much can national maize production in Ethiopia
be increased when yield gaps are closed?
45
40
35
All yield gaps
closed
economic
optimal
application of
fertilizer
National
maize
production
in 2013
(FAOSTAT)
All policies
combined
million tons
30
25
Extension
services for
all plots
20
Application of
improved
seeds
15
10
5
0
Tot. prod.
Ext. services
Fertilizer
Impr. seeds
All policies
Yg close
Main findings
 Technology gap (57%) makes up the largest component of
the yield gap.
 Economic constraints (30%) make up the second largest
component of the yield gap
● It is not profitable for farmers to use more fertilizer given
current yield response and input and output prices.
● Using improved seeds substantially increases yield.
 Technical efficiency makes up 10% of the total yield gap.
● Extension services have a positive (but small) effect on
technical efficiency.
18
Policy messages

Expanding extension services to all farms will increase maize
yield.

Improved farm management practices are required to close the
technical efficiency yield gap.

Profitability analysis suggest that input and output prices are such
that farmers do not have an incentive to expand production
beyond the current level.

Stimulating the use of improved seeds has the potential to
increase maize yield (but there might be economic constraints).

Closing the (technology) yield gap requires the diffusion of
transformative technologies, policies and practices (e.g.
precision farming).

19
Thank you
Questions?
20
Methodology to operationalise framework
1. Take actual maize yield from LSMS-ISA
2. Estimate frontier/technically efficient yield
● Using stochastic frontier analysis
3. Compute profit maximizing fertilizer (nitrogen) use
● Short run profit maximization under the
assumption that capital and labour are fixed and
fertilizer is variable
● National level maize and fertilizer prices
4. Take yield potential from GYGA
21
Methodology
1. Take actual maize yield from household survey
2. Use yield response function for best-practice
farms/plots to estimate technical efficiency yield
3. Use regional maize and fertilizer prices to calculate
economic yield
4. Estimate feasible yield using assumptions on input
use
5. Take potential water-limited yield from GYGA
6. Calculate yield gaps
22
Yield levels

Potential (water-limited) yield: Biophysical maximum production
level determined by CO2 emissions, solar radiation and climate (but
constrained by water resources).

Feasible yield: Maximum yield that can be achieved on a plot with
available technology and best-practice management assuming no
economic constraints.


Economic yield: yield level at which profits are maximized.

Actual yield: Observed yield at the plot level.
Technical efficient yield: measures best-practice performance at
each input level.
23