Presented by Yohannes Regassa May 9, 2019, as part of the first CCAFS & GRA CLIFF-GRADS Webinar Series. See the Introduction for more details: 2019 CLIFF-GRADS Webinar Series - Using modeling, life cycle assessment, and trade-off analysis to understand low emissions development options.

1. YOHANNES G. REGASSA
Preliminary Experimental Results of Different Water and Nutrient
Management Practices for Narrowing Maize Yield Gap in Ethiopia

2. Purpose of research
• Total Area = 1.12 m km2
(46% suitable for agriculture)
• Population = 100 million
• Agriculture Provides
- 43% of GDP
- 85% of Employment
- 90% of Export revenue

3. Major food security crop in Ethiopia
Source: CSA, 2017
Teff (4.3 million metric tone)
Wheat (4.1 million metric tone)
Maize (7.9 million metric tone)

4. Potential Yield of Maize = 6 to 9 Mg ha-1
• Yield levels obtained by smallholder farmers remained stagnant (2 Mg
ha-1)
• The main causes for this discrepancy
• low soil fertility , land degradation, pests, low inputs use, and
climate variability (FDRE, 2013; Waddington et al., 2010; ATA 2013)
• Objective of the research
to evaluate the effect of different nutrient management practices on
maize grain yield gap in response to different in situ water harvesting
techniques

5. Research methods
In the experiment
• 20 farmers in 2 locations (Kobo and Dewacheffa districts in the rift valley of
Ethiopia)
• Treatments: 5 nutrient sources and 4 water conserving practices were used
factorial combination
• Experimental Design= RCBD
• Plots size = 80 m2
• Test crop: Melkassa-2
Empirical statistical analyses, and a systems analytical approach, through using field
experimental data in combination with crop-climate simulation models were used
in this study.

6. Results Kobo Site
3209 3494.4
4595
5365
3018.6
0
1000
2000
3000
4000
5000
6000
Improved
fallow
Green manure Inorganic
fertilizer
Integrated
NM
Unfertilized
Yield(kgha-1)
Maize grain yield as influenced by nutrient management practices
Yield increment = 41.1 to 92.6% over the control Yield increment = 11.4 to 35.3% over the control
3936.4 4075.08
3058.8
3351.76
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Yield(kgha-1)
Maize grain yield as influenced by water management
Drought resistant cropZai technique Tied ridge Control
a
b
c
d
c
c
a
b
a

7. Results
• A few key results
Dewacheffa site
0
1000
2000
3000
4000
5000
6000
Zaitechnique
Tiedridge
Droughtresistant
Flatbed
Zaitechnique
Tiedridge
Droughtresistant
Flatbed
Zaitechnique
Tiedridge
Droughtresistant
Flatbed
Zaitechnique
Tiedridge
Droughtresistant
Flatbed
Zaitechnique
Tiedridge
Droughtresistant
Flatbed
Improved fallow Green manure Inorganic fertilizer Integrated NM Unfertilized
Yield(kgha-1)
Maize grain yield as influenced by water and nutrient management
a
bb
ccd
dde de
e e
f f
k
j
f gghf
hi
ii
41.7 to 201% over the control treatment

8. Preliminary Conclusions
• Kobo site
• application of Integrated nutrient management provide
best maize grain yield (76% narrow the yield gap)
• tied ridge practices also yields higher maize grain yield
(58% narrow the yield gap)
• Dewa-cheffa
• A combination of integrated nutrient management with
tied-ridge water conservation technique provide best
maize grain yield (89% narrow the yield gap)

9. Advice to future CLIFF-GRADS students
• So far so good, but there is additional thing to be considered in CLIFF-
Grads program, i.e., creating the research fund opportunities to
young African scientists in addressing climate change and variability,
with specific solutions for smallholder farmers