Presented by T. Erkossa, A. Haileslassie and C. MacAlister at the Nile Basin Development Challenge (NBDC) Science Workshop, Addis Ababa, Ethiopia, 9–10 July 2013

1. Land Use and Water Management in Rainfed Agriculture
for Enhanced Systems Productivity:
The case of Vertisol Areas in the Blue Nile Basin
T. Erkossa 1
, A. Haileslassie 2
, C. MacAlister 3
Nile Basin Development Challenge (NBDC) Science Workshop
Addis Ababa, Ethiopia, 9–10 July 2013

2. Agriculture- Crop and Livestock farming is the main
source of livelihood in the basin
Challenges to Agriculture in the Basin:
– Extreme biophysical variations
– Population pressure and land degradation
⇒Shortage of land
⇒Encroachment to marginal lands
⇒Reduced land and water productivity (average
grain yield < 1 T/ha)
– Lack of site specific technologies
• Limited use of improved technologies
Increasedpoverty,foodinsecurity&
Vulnerabilitytoclimatechange
Required: Identification +Disseminate of Site specific Technologies
Introduction

3. The Case of Vertisols
o Among the high potential
soils
o Located in areas with
favorable climate
o LGP ranges from 120-190
days
o About 12 million ha in
Ethiopia
o 12% of the Abay Basin (≈12% of the Abay Basin (≈
2.7 million ha)2.7 million ha)o

4. o Productivity is constrained
by their hydro-physical
characteristics
o Severe water logging
during rainy season
Required level
Deficit
Water Management Challenges
Growing Season
Excess Water logging
Defic
it
Agricultural Constraints of Vertisols

5. • Traditional:
 Late planting on flat beds-Late planting on flat beds- crops grow oncrops grow on
residual moistureresidual moisture
 Tolerant crops-Tolerant crops- low yielding or not preferablelow yielding or not preferable
• Hand made BBF-Hand made BBF- backbreaking taskbackbreaking task
Management Options
Hand made BBF
BBF made by BBM
• Improved:
 Surface drainage (BBF)-Surface drainage (BBF)- made by animalmade by animal
powerpower
 Tolerant and high yielding cropsTolerant and high yielding crops

6. CROPWAT: ETc and
Eff. rain
Vertisols
Drainable (2-5%)
slope
Undrainable (<2%
slope)
Alternative
s
Weather, soil,
Climate
National Met.
Stations, NewLocClim
Estimates
Surface drainage + Early
planting
Flat bed + Late Planting
System WP
Livestock
WP
Livestock feed
(Straw)
Crop
WP
Tolerant and high yielding
crops
Natural pasture
Crop yield: field
monitoring, research
reports

8. Supported by: CPWF
• Globally agriculture accounts for 70% of all fresh
water withdrawals and 90% of the consumption
• Agricultural WP increase by 1% means 10% increase
in water availability for other uses
• Rainfed agriculture dominates the farming system
(>90%)
• Improving WP of the rainfed system enhances
livelihood in the US and increases water availability
for the DS
Why Agricultural Water Productivity

9. Location and year Grain Straw
BBF Flat % increase due
to BBF
BBF Flat % increase due
to BBF
Enewari (1986) 1105 1072 3 1590 1543 3
Dogollo (1986) 1844 1258 47 2654 1810 47
Dejen (1987) 1263 918 38 1817 1321 38
Bahir Dar (2007) 2600 2000 30 3741 2878 30
Merawi (2007) 1700 600 183 2446 863 183
Bichena (1997) 1600 900 78 2302 1295 78
Average 1685 1125 63 2425 1618 63

10. Location and year Grain WP with respect to eff.
rainfall (kg m-3
)
WP with respect to actual
ETc (kg m-3
)
BBF Flat % increase due
to BBF
BBF Flat
Enewari 1986 0.23 0.22 5 0.37 0.99
Dogollo 1986 0.32 0.22 45 0.58 0.49
Dejen 1987 0.22 0.16 38 0.42 0.77
Bahir Dar 2007 0.34 0.26 31 0.93 0.82
Merawi 2007 0.30 0.10
200 0.54 0.50
Bichena 1997 0.34 0.19 79 0.53 0.83
Average 0.33 0.24 57 0.66 0.89
Land Preparation Methods Effect on Grain WP of wheat with
respect to eff. rain and ETc

11. Location Gross return (USD ha-
1
)*
WP (USD m-3
)
BBF Flat BBF Flat % increase due to BBF
Enewari 1986 545 529 0.12 0.11 3
Dogollo 1986 910 621 0.16 0.11 47
Dejen 1987 623 453 0.11 0.08 38
Bahir Dar 2007 1282 986 0.17 0.13 30
Merawi 2007 839 296 0.15 0.05 183
Bichena 1997 789 444 0.16 0.09 78
Average 831 555 0.14 0.09 56
*Wheat grain price estimated @ 0.4932USD kg-1

12. Effect of Land use on WP with respect to effective Rainfall
of Undrainable Vertisols
Land use Average grain
yield (kg ha-1
)
Average eff.
rain (m3
ha-1
)
Grain WP
(kg m-3
)
Biomass (grain + straw)
WP (kg m-3
)
Rice 3596 7900 0.46 1.0
Grass-pea 4662 7900 4895 1.8
Natural
pasture
Biomass (kg ha-1
) Average eff.
rain (m3
ha-1
)
2793 6330 0.44
Results- Undrainable Areas

13. Integration (Systems approach)
• Improving crop water
productivity
• Value addition: Feed crop
residue to livestock
• Improving livestock
productivity
• Improve livestock
management
• Improve crop-livestock
System Productivity
Example: Crops - livestock
USDha-1

14. • BBF increased crop yield and WP with respect to
effective rainfall, and reduced evaporation loss
• Growing rice increased overall WP despite increased
water consumption, due to its reduced evaporation
• Use of BBF on drainable land and rice on flat land
increased Economic WP
• Integrating crop-livestock system; for example through
feeding the crop residues to the livestock enhanced
overall SWP