5.4
Sorghum Agronomy in Ethiopia
Dr. Ketema Belete, Haramaya University
Agronomic/cultural practices
1.Tillage
2. Seeding methods
3.Fertilizer application
4. Irrigation
5. Weed control
6. Plant protection
Why sorghum?




Major cereal in moisture limited areas
One of the most drought resistant cereal ‘CROP CAMEL’
In Ethiopia – source of food, fodder, fuel and building material
Crop
Pearl millet
Sorghum
Maize
Wheat
Units of dry matter produced for
every 1000 units water consumed
3.64
3.46
2.88
1.93
Agronomic/cultural practices
1. Tillage
 Purpose of tillage
a. Improvement of soil structure
b. Moisture conservation
c. Soil aeration
d. Root penetration
e. Weed control
F Seedbed preparation
Agronomic/cultural practices …
2.. Seeding methods
2.1. Planting date - rule of thumb ‘availability of moisture at
planting & during the
vegetative/reproduction stage & its absence after maturity and at
harvest’
2.2. Planting depth
 Depends on seed size & soil type
 2.5 to 5cm for sorghum vs 5 to 8cm for maize
Agronomic/cultural practices ...
2.3. Seeding rate/ Row spacing/Planting density
 Depends on variety, fertility of soil & moisture
 in Ethiopia 5 to 8 kg/ha
 in US 7.5 to 12 kg/ha
 in Ethiopia 75 x 20cm, 75 x15cm
 in US 90 x15cm (rainfed), 75x15cm (spate irr.)
 in Ethiopia 67 000 to 90 000 plants/ha
 in US 75 000 to 125 000 plants/ha
Plant density
 In Ethiopia since sorghum is used for fodder is
constantly thinned – affecting the total yield
 This is due to a scarcity of other sources of fodder
 If intercropped with Labla this could be overcome
Agronomic/cultural practices ...
3 Fertilizer application
 in Ethiopia
 N and P ( N kg/ha and P2O5kg/ha)
 DAP source of N and P at planting
 Urea source of N at knee height
 Important to have tailor-made applications
 Economical under dependable rainfall & irrigation
 In some spate soil natural fertility very high – would not need
additional fertilizer – this would in fact even damage the crop
Agronomic/cultural practices ...
4 Weeding/ control of Striga
 Microscopic seeds that can survive more than 20 yrs
 Seeds tap into rootstems of sorghum and ‘suck’ it
 If enough fertilizer/ moisture sorghum will be able to handle
striga
 Approach:
Use fertilizer/ moisture
Use stryga resistant varieties
Need to think of short duration varieties
 At the moment most sorghum varieties in Ethiopia are
late-maturing
 This is in line with the practice of rain-fed farming and
the year-round multipurpose functions of sorghum
 In spate irrigated areas – especially in the lowlands
where there is no supplementary rainfall - short
duration varieties are more useful
Production Statistics of Sorghum
Grain in 1998 (Source UN 1999)
Country
Egypt
Eritrea
Ethiopia
Kenya
Sudan
India
US
Harvested area (103ha)
156
236
982
140
6405
10238
3125
Average yield (Kg/ha)
5769
1144
1103
929
671
833
4226
Agronomic/cultural practices ...
5. Irrigation
- not widely used in Ethiopia for cereal production
- stored soil moisture for maximum yield is 50 to 60 cm
- preplant irrigation that wets the soil to field capacity to a
depth of 2m is best – signifying the importance of adequate
moisture conservation
- maximum water usage occurs
- at boot stage of the plant growth
Amount of water extracted from various depths by a
sorghum crop during a growing season (W.M.Ross& O.J.Webster.
1970. Culture and Use of Grain Sorghum)
Soil Depth (m)
Percent of Total
0.0-0.3
Water Absorbed
(cm)
22.6
0.3 - 0.6
16.8
26
0.6 - 0.9
10.2
16
0.9 - 1.2
7.1
11
1.2 -1.8
3.3
5
35
Daily water use for grain sorghum
This is when crops need
most water – this can
also be provided from
conserved moisture and
capillary rise (in colder
season)
In this season no irrigation or
rainfall is required – it would
only delay the drying of the
seed and the harvest
10
8
6
4
2
0
0
7-leaf Rapid
stage growth
stage
20
40
Boot
stage
60
Bloom
stage
80
Grain
filling
stage
Days After Planting
100
Harvest
120
140
Interaction of Irrigation and Fertilizer
(E.F.Bennett., B.B. Tucker& A. B. Maunder. 1990. Modern Grain Sorghum
Production)
Some effect
but not
dramatic
Time and number of irrigation
Preplant and preboot, 2 Irr
Preplant, preboot, and milk, 3 Irr.
Preplant, preboot, flower, and
milk, 4 Irr.
Grain Yield (Kg/ha)
No fertilizer
With fertilizer
5645
5799
5964
6468
7039
8120
General points

Average yield of irrigated sorghum have increased by 82%
more than non-irrigated sorghum
 Moisture needed to produce acceptable yield is approximately
40 to 50 cm
 Maximum yield requires 50 to 65 cm moisture
 Roots of sorghum extract soil moisture from up to 2m of soil
depth.
Water use by the plant

At planting
it is needed for good seed to soil content
adequate soil moisture
proper germination temperature (min. 10oC)
the above 3 ensure good stand establishment
Water use by the plant (cont..)

At Seedling stage
amount of moisture taken up is low
availability of sufficient moisture is critical
root zone is less than 45 cm, thus deeper soil moisture is not needed
soil moisture is not depleted rapidly
more moisture is lost by evaporation from soil than transpiration
through the crop canopy
water conservation practices to minimize soil moisture losses
•
•
•
•
residue management
narrow row spacing
proper planting date
weed control
Water use by the plant (cont..)

At rapid growth stage and reproduction stage (Example based
on early maturing variety 150 days)
starts as of about 30 days after emergence (7 to 8 leaves
stage)
pick at boot stage and bloom stage (about from 50 to 80 DAE)