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

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 landEncroachment to marginal landsReduced land and water productivity (average

grain yield < 1 T/ha)– Lack of site specific technologies

• Limited use of improved technologies

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Required: Identification +Disseminate of Site specific Technologies

Introduction

The Case of Vertisolso Among the high potential

soils o Located in areas with

favorable climateo LGP ranges from 120-190

dayso About 12 million ha in

Ethiopiao 12% of the Abay Basin (≈ 12% of the Abay Basin (≈

2.7 million ha)2.7 million ha)o

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

Deficit

Agricultural Constraints of Vertisols

• Traditional: Late planting on flat beds- Late planting on flat beds- crops grow on crops grow on

residual moistureresidual moisture Tolerant crops- Tolerant crops- low yielding or not preferable low 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 animal made by animal

powerpower Tolerant and high yielding cropsTolerant and high yielding crops

CROPWAT: ETc and Eff. rain

Vertisols

Drainable (2-5%) slope

Undrainable (<2% slope)

Alternatives

Weather, soil, Climate

National Met. Stations,

NewLocClim Estimates

Surface drainage + Early plantingFlat bed + Late Planting

System WP

Livestock WP

Livestock feed (Straw)

Crop WP

Tolerant and high yielding cropsNatural pasture

Crop yield: field monitoring, research reports

18/11/2009, Addis AbabaSupported 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

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 183Bichena (1997) 1600 900 78 2302 1295 78

Average 1685 1125 63 2425 1618 63

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 19860.23 0.22 5 0.37 0.99

Dogollo 19860.32 0.22 45 0.58 0.49

Dejen 19870.22 0.16 38 0.42 0.77

Bahir Dar 20070.34 0.26 31 0.93 0.82

Merawi 20070.30 0.10 200 0.54 0.50

Bichena 19970.34 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

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 38Bahir 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

Effect of Land use on WP with respect to effective Rainfallof 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 1.0Grass-pea 4662 7900 4895 1.8Natural pasture

Biomass (kg ha-1) Average eff.

rain (m3 ha-1)

2793 6330 0.44

Results- Undrainable Areas

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

US

D h

a -1

• 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