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 Table of Contents
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 Summary
 Introduction
 Materials and methods
 Overview of wheat production in...
 Results and discussion
 Conclusion
 Acknowledgement
 Reference
 Maps






Group Title: Geographic information systems series - Natural Resources Group - 01-01
Title: An agro-climatological characterization of bread wheat production areas in Ethiopia
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 Material Information
Title: An agro-climatological characterization of bread wheat production areas in Ethiopia
Series Title: Geographic information systems series
Physical Description: vi, 14 p. : ill., maps ; 28 cm.
Language: English
Creator: White, Jeffrey W
Tanner, Douglas G
Corbett, John D
International Maize and Wheat Improvement Center
Publisher: Published jointly by the Wheat Program and the NRG
Place of Publication: Mexico
Publication Date: c2001
 Subjects
Subject: Wheat -- Climatic factors -- Ethiopia   ( lcsh )
Genre: international intergovernmental publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 9).
Statement of Responsibility: Jeffrey W. White, Douglas G. Tanner, and John D. Corbett.
General Note: At head of title: CIMMYT International Maize and Wheat Improvement Center.
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Bibliographic ID: UF00077517
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: African Studies Collections in the Department of Special Collections and Area Studies, George A. Smathers Libraries, University of Florida
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Table of Contents
    Title Page
        Page i
    Copyright
        Page ii
    Table of Contents
        Page iii
    List of maps
        Page iv
    Summary
        Page v
    Introduction
        Page 1
    Materials and methods
        Page 2
    Overview of wheat production in Ethiopia
        Page 3
    Results and discussion
        Page 4
        Page 5
        Page 6
        Page 7
    Conclusion
        Page 8
    Acknowledgement
        Page 8
    Reference
        Page 9
    Maps
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
Full Text





II
CIMMYT.
INTERNATIONAL MAIZE AND WHEAT
IMPROVEMENT CENTER




An Agro-Climatological
Characterization of Bread Wheat
Production Areas in Ethiopia

Jeffrey W. White,1 Douglas G. Tanner,2 and John D. Corbett3


Published jointly by the
Wheat Program
and the

N R.G
NRG
Natural Resources Group


Geographic Information Systems
Series 01-01


GIS and Modeling Lab, Natural Resources Group, CIMMYT
Agronomist, CIMMYT Wheat Program, Addis Ababa, Ethiopia
Blackland Research and Extension Center, the Texas A&M University Research System



















CIMMYT (www.cimmyt.org) is an :- .:-,:-:-.-ii, funded, nonprofit, scientific research and
training organization. Headquartered in Mexico, CIMMYT works with agricultural research
institutions worldwide to improve the ... !,. ii :ii i .. ..i1 I :. and sustainability of maize and
wheat systems for poor farmers in developing countries. It is one of 16 food and environmental
organizations known as the Future Harvest Centers. Located around the world, the Future Harvest
Centers conduct research in partnership with farmers, scientists, and policymakers to help ..i .1
poverty and increase food security while protecting natural resources. The centers are supported
by the Cor-,::I-,: Group on International Agricultural Research (CGIAR) (www.cgiar.org),
whose members include nearly 60 countries, private foundations, and regional and international
c.! i! : _., :. .i .. Financial support for CIMMYT's research ...; -.. .: also comes from many other
sources, including foundations, development banks, and public and private agencies.

Future Harvest@ builds awareness and support for food and environmental research for a
world with less poverty, a :i!... human family, ii nourished children, and a better
environment. It supports research, promotes partnerships, and sponsors projects that bring the
results of research to rural communities, farmers, and families in Africa, Asia, and Latin America
(www.futureharvest.org).

International Maize and Wheat Improvement Center (CIMMYT) 2001. All rights reserved. The
opinions expressed in this publication are the sole responsibility of the authors. The designations
employed in the presentation of materials in this publication do not imply the expression of any
opinion whatsoever on the part of ( i: i: :YT or its contributory i : ,;i i.: ... concerning the legal
status of any country, territory, city, or area, or of its .-, n-..:. : -, or concerning the delimitation
of its frontiers or boundaries. CIMMYT encourages fair use of this material. Proper citation is
requested.

Correct citation: White, J.W., D.G. Tanner, and J.D. Corbett. 2001. An Agro-C ..:'-r-.--.--*
Characterization of Bread Wheat Production Areas in L ',.:...., NRG-GIS Series 01-01. Mexico,
D.F.: CIMMYT.

Abstract: This report describes a GIS-based assessment of the distribution of wheat production
in Ethiopia, with emphasis on climate factors limiting the potential wheat area and using mainly
agro-climatological characteristics obtained from interpolated climate data contained in the
Ethiopian Country Almanac. Results suggest that the greatest opportunity for expanding wheat
production in Ethiopia would involve increasing the tolerance of wheat to warmer growing
conditions but that other factors, including the adaptation of current and/or alternate crops,
c : li land-use suitability, and market constraints must be considered before moving wheat into
new areas. Site similarity analyses f :: -. :- suggest that the current distribution of wheat research
sites in _:i ...- ... provides a reasonable coverage of the traditional wheat production area in terms
of climatic conditions, and support the relevance of the Kulumsa station for wheat research
throughout much of Eastern and Southern Africa.

ISSN: 1405-7484
AGROVOC descriptors: Soft wheat; Wheats; Food production; Temperature resistance;
Climatic factors; Precipitation; i....v: zones; ( i::.. ~ -. -9, Ethiopia.
AGRIS category codes: P40 Meteorology and Ci; ....-: E14 Development Economics
and Policies
Dewey decimal classification: 633.1


Printed in Mexico.
















Contents


Page
v Summary
1 Introduction
2 Materials and : -:--!
3 Overview of Wheat Production in Ethiopia
4 Results and Discussion
8 Conclusions
8 Acknowledgments
9 References



Tables


1 Table 1. Comparison of human population, per capital income, wheat area,
wheat production and other parameters for Ethiopia and ir I
countries in sub-Saharan Africa i .:.: Aquino et al. 1
2 Table 2. Sites referred to in the text or indicated in Maps 1 or 7.
5 Table 3. Comparison of elevations and climate for four sites in ..
using data from the Ethiopian Country Almanac (ECA) and actual
meteorological station data (courtesy of EARO). Climate data are for
the wettest quarter.


Figures


3 Figure 1. Annual variation in climate at Kulumsa, Ethiopia.
4 Figure 2. Relationships between total precipitation (A) and elevation (B) and
mean minimum temperature during the wettest quarter for 180 wheat
germplasm accessions c .::- :- I in Ethiopia.
7 Figure 3. Variation in wheat grain yield at Kulumsa, Ethiopia, as simulated
for changes in growing season total precipitation (A) and mean
temperature (B).
















Maps


Page
10 Map 1. Approximate distribution of traditional wheat production areas
of Ethiopia and the location of sites mentioned in this paper
(re-drawn from Belay et al. 1999)
10 Map 2. Approximate distribution of traditional wheat production areas
of fin ,I superimposed on climatic zones of :ii.- i where
precipitation is over 350 mm and the mean minimum temperature
is between 60 and 11 C during the wettest quarter of the year.
The darkest areas in the -. :ri have a growing season greater
than 9 months, based on P/PE greater than 0.5.
11 Map 3. Areas of Ethiopia where precipitation is over 350 mm, the mean
minimum temperature is between 60 and 11 C during the wettest
quarter of the year, and the growing season is 9 months or less.
The : --! hatched zones represent elevations above 2000 m.
11 Map 4. Approximate distribution of traditional wheat production areas of
Ethiopia re-drawn from Belay et al. (1999), the proposed climate-
based wheat zone, and 180 wheat germplasm ii i.. ., sites.
12 Map 5. Areas of -i: i ,. :i where precipitation is over 350 mm, the mean
minimum temperature is between 60 and 11 C during the wettest
quarter of the year, and the growing season is 9 *.... i or less.
The additional dark areas receive between 300 and 350 mm of
precipitation during the wettest quarter of the year.
12 Map 6. Areas of Ethiopia where precipitation is over 350 mm, the mean
minimum temperature is between 6 and 11 C during the wettest
quarter of the year, and the growing season is 9 months or
less. The additional dark areas have mean minimum temperatures
between 110 to 130C during the wettest quarter of the year.
13 Map 7. Areas :i.:: Ethiopia '., .. .i climatic conditions during the
wettest quarter that are similar to those of one of eight wheat
research sites in the country.
14 Map 8. Areas in sub-Saharan Africa having climatic conditions during the
optimal -. ..._ .. i: _.. "i .i season that are similar to those at
Kulumsa, ii: .i










Summary


This report describes a GIS-based assessment
of the distribution of wheat production in 11i: ,i : ..
with emphasis on climatic factors limiting the
potential wheat area. Analyses relied primarily on
agro-cli.... .'. i_-..*i characteristics obtained from
interpolated climate data contained f,. the
1 1:. :i : .:. Country Almanac; the same GIS-based tool
was used to analyze climatic data related to current
and potential wheat production areas in -::i; -
Based on consultations with _i ...i.. wheat
scientists and examination of a published map
approximating the geographic distribution of current
wheat production, traditional rainfed wheat
production areas were best described in a zone with
350 mm or more precipitation and mean minimum
temperatures of 6C to 11C during the wettest
quarter (i.e., three consecutive months). The lower
i.! i. limit for this zone is rn : Jl.l 2,000 m. The
wettest quarter was used to restrict planting to the
onset of the "meher" (long-season) rains; planting at
the onset of the "belg" (short-season) rains would
expose the maturing wheat crop to high ,.i ii
during the succeeding meher.
Precipitation and temperature limits were tested
further by comparing them to climatic conditions at
180 wheat germplasm collection sites in L "*'-i...
Results suggested a similar lower limit for precipitation
and minimum temperature range, but a higher upper
limit for minimum temperature range, although many
--ii --.- were made at lower sites (for example,
along major roads and in markets) that are warmer
than actual wheat .- :..i areas.


Examining the potential for wheat cropping in
drier or warmer environments, it was found that
l.. ::. j production in areas with as little as 300 mm
of precipitation during the wettest quarter resulted in
the addition of a small area, primarily in the :-. i-, -r
near the Sinana research station. In contrast, raising
the upper limit of the minimum temperature range by
20C would perhaps double the potential wheat area
on the periphery of the highlands, due to a mean
rainfall of over 500 mm during the wettest quarter
in such areas. Thus, the present agro-climatological
constraint on wheat area is not lack of rainfall but
warm temperatures. This suggests that attempts
to identify new productive areas should focus
on strategies for r : --.: ...;-.-i heat stress and on
resistance to wheat diseases associated with warmer
environments, subject of course to soil suitability,
the presence of other crops, labor availability, and
other socioeconomic factors in the areas identified
for expansion.
On examining the distribution of eight wheat
research stations, we found that the present set of
stations covered most Ethiopian wheat zones and
exhibited little overlap. In a broader similarity analysis
for the Kulumsa station (a key center for wheat
research in Eastern Africa), the climate at that location
was similar to those of major wheat-producing areas
of Kenya and _::" .... as 11 as in the Great Lakes
Region i .!. i southwestern Uganda, and the
North Kivu district of the Democratic Republic of the
C -! -.' northern Tanzania, and Lesotho.


a









An Agro-Climatological

Characterization of Bread Wheat

Production Areas in Ethiopia


Introduction


Ethiopia is the second largest producer of wheat
in sub-Saharan Africa, fi., i. ...i South Africa (Table
1). About 91C' *., ha of bread (Triticum aestivum)
and durum (T turgidum var. durum) wheats are
grown in Ethiopia, primarily as '-: i-.',- :-"- rainfed
crops. Mean wheat yields are around 1.4 t/ha, .-:
below experimental yields of over 5 t/ha (Hailu
1991). f,: ." current annual wheat production
of approximately 1.3 ,:ii: :: tons is insufficient to
meet domestic needs, forcing the country to import
30 to 50% of the annual wheat grain required.
The yield gap of over 3 t/ha suggests the potential
for increasing production ::; .._.h improved crop
management, particularly increased use of fertilizers.
However, there is also justification for examining
whether wheat production can be introduced to non-
traditional areas. Geographic information systems
(GIS) provide a way to do this, .!ii. .. .; researchers to
examine crop distribution in relation to climate and
other factors.


This paper first examines the current distribution
of wheat production in relation to climate. Itthen uses
the described climatic limits as the basis for evaluating
the potential for increasing wheat production area in
L ri ..-.i- To understand the possible contribution that
different research centers -..1 l, make to improving
wheat production in current or potential wheat
areas, climate similarity analyses were conducted for
research stations used by the cooperative National
Wheat Research Program coordinated under the
auspices of the Ethiopian Agricultural Research
Organization (EARO).
Emphasis is given to the use of quantitative
characterizations based on climate data that have
been interpolated over all of Africa (Corbett and
O'Brien 1997). This ensures that mapped distributions
are more fully testable and reproducible, thus
contributing to a more precise understanding of
the adaptation of wheat in Ethiopia as well as in
other countries.


Table 1. Comparison of human population, per capital income, wheat area, wheat production, and
other parameters for Ethiopia and other countries in sub-Saharan Africa (from Aquino et al. 1996).


Ethiopia Kenya South Africa Sudan Zambia Zimbabwe


Estimated population, 1995 /.. .-,
Estimated growth rate of population,
1993-2000 (% per year)
Per capital income, 1994 (US $)
Average wheat area harvested,
1993-1995 (000 ha)
Average wheat yield, 1993-1995 (t/ha)
Average wheat production,
1993-1995 (000t)
Average net imports of wheat,
1992-94 (000 t)
Nitrogen .i i i: i, 1993-1994 (kg N/ha)


58.6

3.0
100

884
1.4

1,270

391
5


41.5

2.2
3,040

1,166
1.7

1,983

557
60


9.5 11.3


2.7 2.6
350


483 55 199

460 28 90
87 62 160


a










Materials and Methods


The primary data source for the climatic analyses
were the climate surfaces for Africa developed
by Corbett (1994) using thin plate smoothing
splines (Hutchinson 1995). In this technique, monthly
mean data for precipitation and temperature are
interpolated from point data corresponding to long-
term records of meteorological stations. This variant
of spline techniques ..i. use of data from a digital
elevation model (: 1 i : ;, ,ii, a topographic map
converted to grid-based format) to improve the
estimation of variation in climate with elevation.
The DEM had a 2.5 arc-minute grid size, which
is roughly equivalent to a 5 km x 5 km grid size
for regions near the equator. In addition to the
basic climate variables, the set of surfaces includes
data for potential evapotranspiration (PET) and ratios


of precipitation to PET (P/PET). These variables are
provided both on an annual basis and for various
season models, including an optimal season defined
as the : !-..,::i period with the highest value of
P/PET and the wettest quarter defined as the three
consecutive months with the greatest precipitation.
Climate data for long-term monthly means at
specific sites were obtained from the FAO climate
database for Africa ,: -*.- 1984). A list of the locations
considered in the current study is given in Table 2; the
locations are also shown in Map 1.
Zones for climate and site similarity within
-: ... i- were defined using the Ethiopia Country
Almanac (ECA), a component of the Country Almanac
Series of CD-ROM-based data sets and tools for
manipulating spatial data (Corbett et al. 1999).


Table 2. Sites referred to in the text or indicated in Maps 1 or 7.

Latitude Longitude Elevation
Site (N) (OE) (m) Comments

Addis Ababa 9.03 38.75 2,354 Capital city of Ethiopia, wheat production area, waterlogging
on Vertisols.
Adett 11.27 37.48 2,240 Wheat research site, waterlogging on Vertisols,
low *:: fertility on Nitisols.
Alemaya 9.50 41.02 1,950 Maize and wheat research site, moisture stress zone.
Ambo 9.05 37.82 2,225 Key highland maize research site, waterlogging on Vertisols.
Asasa 7.13 39.21 2,360 Wheat research site, relatively short growing season with
terminal moisture stress.
Awassa 7.05 38.47 1,750 Maize research site.
: 7.53 39.25 2,780 Wheat research site, high rainfall, long growing season.
Debre Markos 10.35 37.73 2,440 Wheat production area, waterlogging on Vertisols.
Debre Zeit' 8.73 38.97 1,900 Durum research coordinating center, waterlogging on Vertisols.
Ginchi 9.03 38.15 2,250 Wheat research site, waterlogged Vertisol.
Goba 7.02 39.98 2,710 Wheat production area, bimodal rainfall.
Gondar 12.60 37.47 1,967 Wheat production area, high :,-;ii
Holetta' 9.05 38.50 2,400 Wheat research site, Septoria hotspot, waterlogging on
Vertisols.
Kulumsat 8.00 39.15 2,200 National bread wheat research coordinating center.
Mekelle' 13.30 39.29 2,050 Capital city of Tigray Region, frequent droughts.
Sinana' 7.13 40.02 2,400 Wheat research site, bimodal rainfall.
WeldiyaT, 11.75 39.60 2,320 Wheat production area.

Sites characterized by ci ..... ,! .!i.: .i1, analyses in Map 7.
Actual c. -..-.:....!. refer to a point approximately 20 km west of' .i ...: town that corresponds to a wheat and
barley region i .---, being grown at higher elevations).










Climate zones are defined through map overlay and
selection procedures. Zones of similar climate are
specified by characterizing the climate at the latitude
and longitude of the reference site and then selecting
criteria for similarity. For this study, the similarity
zones were usually based on the wettest quarter
(three-month period) and considered ranges of +/-
50 mm for precipitation and PET and of +/- 1C for
mean maximum and minimum temperatures, unless
otherwise specified. For similarity analyses over all of
Africa, the Spatial Characterization Tool (Corbett and
O'Brien 1997) was used, assuming +/- 10% ranges
for the five most favorable months based on the ratio
P/PET. All maps are presented unprojected, by latitude
and longitude. To verify the limit of zones based on
climatic limits, conditions at specific locations were
also assessed. Presumed wheat production locations
were obtained based on collection sites of bread
wheats as listed in the USDA GRIN database (USDA-
ARS-NGRP 2000).
Simulations of wheat crop growth and
development were conducted using CERES Wheat
V3.50[98.0] (Hoogenboom et al. 1994; P. Wilkens,
personal communication, 1999). A 10-year set of
weather data from Kulumsa, Ethiopia, was used in
conjunction with a generic soil profile for a sandy


loam assumed to allow root growth to a depth
of 0.9 m. Seed was broadcast at a density of
180 plants/m2 and fertilized each year with 10 kg of
nitrogen. A window for sowing date from 1 July to 1
August was allowed.


Overview of Wheat
Production in Ethiopia


In Ethiopia, wheat is grown primarily as a rainfed
crop by smallholders in the highlands (Map 1). In most
of the country, only a single wheat crop is grown
during the second, longer rainy season (meher)
which usually starts in June (Fig. 1). The short rains
(belg), starting in March, are less reliable in most
parts of Ethiopia; however, in the southeast of the
country (e.g., Bale zone of Oromiyia Region), rainfall
distribution is bimodal. Growing wheat in belg season
implies harvesting during meher, which often results
in high grain moisture levels and sprouting. Thus,
wheat crops are typically sown by broadcasting in
June or July and harvested in November or December
(Hailu 1991). A very small area has also been grown
as a winter crop under irrigation on state farms at
lower elevations (Jamal 1994).


Figure 1. Annual variation in climate, Kulumsa, Ethiopia.

in---


J F M A M Jn JI A S O N D
Month


25-

- 20-
S -
1 15-

E
o-
10-

5-


160

-140

-120 E
E
-100
o
0
-80 p

-60 .-

-40 "

-20

-0


3










Bread wheat accounts for roughly 60% of total
wheat production and nearly all cultivars are derived
from modern, semi-dwarf wheats. Durum wheat
accounts for most of the remaining 40%, ..i.-.-,.jh
emmer wheat (T dicoccum L.) is also grown. Bread
wheat is produced at .:_,..,: higher elevations
and on better drained soils than durum wheat,
which is primarily found on poorly drained Vertisols
(Hailu 1991).
Wheat production constraints include low soil
fertility, grass weed infestations, waterlogging in
Vertisol areas, and water deficits in short season areas
(Tanner et al. 1991). Stripe rust (Puccinia ::! :... .: : ; is
common at higher elevations (> 2,400 m); stem rust
(P graminis f. sp. tritici) is more problematic at mid-
elevations C 2,'4-2,400 m) (Bekele and Tanner 1995).
Double-c i.-.:- :, has recently been demonstrated
as a :..i :!.. option for :ii rn Ethiopia
(Tanner et al. 1 i, In the Bale zone of Oromiya
Region, the beig rains are .: f-, .i.T long and reliable
for wheat or other crops. Double cropping could
reduce the negative effects of the current practice
of alternate season i ii a continuous crop cover
would reduce erosion; ilr :.. i crops would help
control weeds; and human and animal power could
be used more efficiently.


Results and Discussion


Present wheat production areas
A review of growing season conditions for
various highland research sites suggested that
precipitation and minimum temperature were key
determinants of potential wheat areas. Setting
requirements of at least 350 mm -::-.-:il and a
minimum temperature between 60 to 11 C during
the wettest quarter (three months) produced a
distribution map similar to the approximation of
traditional wheat production areas reproduced
from Belay et al. (1999; Map 2).
These limits, however, resulted in the inclusion
of a high ..i i .lii area of southwestern Ethiopia that
is too wet for wheat production (annual precipitation
> 1,800 mm). Subsequent consultations indicated
that this area grows '-:i',!-. ':' maize (Zea mays
L.) and enset (Musa ,'., ;'-'. -' which are better
suited to long, wet growing seasons. This zone was
thus excluded from the potential wheat area by
I i !,.!;. I the selection criteria to exclude areas
having a growing season greater than 9 months
(Map 2). The revised wheat zone closely corresponds
to sites exceeding 2,000 m in .,i-r,...i- (Map 3).


Figure 2. Relationships between total precipitation (A) and elevation (B) and mean minimum
temperature during the wettest quarter for 180 wheat germplasm accessions collected in Ethiopia.


0 200 400 600 800


z Z) --------------

20 -

15 *-



10
5-

0


1500


1000 500


Precipitation (mm)


2500


3500


I


-----4--


I


Elevation (m)










To provide an independent estimate of appropriate
temperature and rainfall ranges for wheat production
zones, values for precipitation and mean minimum
temperature during the wettest quarter were obtained
for 180 bread wheat germplasm collection sites in
Ethiopia (Map 4). It is notable that most i..-.i ::
points fell within the derived wheat production zone.
These data also support the lower limits of 350 mm
for precipitation and 60C for minimum temperature
(Fig. 2A) used to develop our wheat distribution map.
However, the upper limit for minimum temperature
proved more problematic, with about half the ( .1: 1i .
sites exhibiting minimum temperatures over 110C
and nine sites '-.-. ;,.-i values over 150C. Comparing
minimum temperature with elevation (as estimated
from the 5 km digital elevation model, not as reported
with the germplasm i..ii.. : data) showed that
some -ii 1! 1 :.. came from locations well below the
suggested 2,000 m limit (Fig. 2B). Fi,'i, i inspection
of passport data for bread wheat accessions suggested
several possible explanations for these discrepancies.
Most accession data did not include information on the
type of i .1i i i., but in cases where this information
was recorded, the seeds often came from markets.
Thus, in many cases, samples may have come from
locations lower than where their source crops were
.._r,_..::, grown. It is also possible that some locations
were erroneously recorded. Hijmans et al. (1999) noted
that i i!qI.I coordinates reported for ii i! .: sites
exhibit high error rates.


The described results must also be qualified in
relation to possible sources of error in the climate
data and the difficulty in attributing objective
limits to ranges of adaptation or climatic similarity.
Although a formal error analysis is not possible,
indirect approaches can give some idea about the
reliability of characterizations.
The climate surfaces have errors attributable
to the source point data, the distribution of the
points, the 5 km grid size of the DEM, and the
interpolation procedure itself. One indicator of the
cumulative effects of these errors is to compare
interpolated values with actual observed data. Table
3 compares interpolated values from the ECA with
actual, measured values for Debre Zeit, Kulumsa,
Holetta, and Bekoji. Elevation figures were w....
200 m of each other. Given the approximate relation
between elevation and temperature, whereby
temperature drops by roughly 0.60C per 100 m
increase in elevation (see Fig. 2B), this discrepancy
should result in an error of roughly 1C in
temperature. In effect, temperature discrepancies
were 'i i. -i of this order and in the expected
direction. Minimum temperature at Holetta was
the notable exception, where a 95 m elevation
difference corresponded to a 0.40C temperature
difference opposite to the direction expected
based on the elevation effect. This suggests that
temperature errors in the current study were
S:" '1 less than 1C. The magnitude of the


Table 3. Comparison of elevations and climate for four sites in Ethiopia using data from the Ethiopian
Country Almanac (ECA) and actual meteorological station data (courtesy of EARO). Climate data are
for the wettest quarter.

Debre Zeit Kulumsa Holetta Bekoji

Data source: ECA Station ECA Station ECA Station ECA Station

Elevation (m) 2,046 1,900 2,130 2,200 2,495 2,400 2,996 2,780
Mean daily maximum temperature (oC) 23.3 24.2 21.9 21.1 20.0 19.8 16.2 17.2
Mean daily minimum temperature (oC) 11.7 12.4 11.0 10.9 9.1 8.7 5.9 7.7
Total precipitation (mm) 576 555 467 376 704 653 525 499
PET (mm) 300 297 257 242


1










discrepancies were lower than those reported for a
similar study in highland Bolivia where a DEM with a
10 km grid cell size was used (Hodson et al. 1998).
Differences between interpolated and observed
precipitation values varied from 21 mm at Debre
Zeit to 91 mm at Kulumsa. Since there is often
no consistent relationship between elevation and
precipitation over large areas, these differences are
not readily attributable to differences between actual
elevation and DEM values. Unfortunately, current
methods for interpolating precipitation data are
extremely dependent on the number, distribution,
and quality of the point data. Models such as PRISM
attempt to improve the interpolations by accounting
for effects of prevailing winds, slope and aspect, and
weather systems ,i ..:.., Resources Conservation
Service Water and Climate Center 1998) and offer
hope for future improvements. Similarly, data on
cloud cover and temperature can be used to improve
estimates of rainfall in an area (Climate Prediction
Center 2000; Arkin and Ardanury 1989), although
values are typically reported on a 10 km grid.

Potential wheat production areas
Because water deficits and warm night
temperatures seemed to be key factors delimiting
bread wheat production areas in Ethiopia, potential
new areas for bread wheat production were identified
by assuming that technologies could be developed
to ..,:i wheat to be grown in drier or warmer
environments. For drier conditions, such technologies
might include more drought tolerant c,:i ,,
supplemental irrigation from small catchments, or
agronomic practices-such as reduced tillage and
residue retention-that reduce runoff. Growing wheat
under warmer conditions might require (.,i. .
with greater heat tolerance as ii as resistance
to pathogens that prevail under warmer conditions
(e.g., Helminthosporium sativum).


Applying the assumption that wheat will grow
in areas receiving as little as 300 mm during the
wettest quarter resulted in a surprisingly :.. il
addition (4%) to the potential wheat production
area (1 :', 5). In contrast, a shift in adaptation
to include areas with 20C warmer minimum
temperatures (e.g., up to 13C) .*i :
increase potential wheat area (Map 6). The actual
impact on total wheat area is impossible to
estimate: zones that meet climate criteria may
have unsuitable soils or topography or already
be used for, i ., more profitable agricultural
pursuits. However, as a rough indicator, increasing
the minimum temperature limit by 20C expanded
the potential area suitable for wheat production by
108%.
These results seem counter-intuitive, given the
popular conception of Ethiopia as an arid, drought-
prone country. The principal explanation is that,
in terms of wheat cropping and ignoring year-to-
year variation, the Ethiopian highlands (to which
the wheat crop is so .. ... represent a
relatively humid environment. Precipitation during
the wettest three months is i! : .i1 well in excess of
PET (Table 3; Fig. 1).

Representativeness of
current wheat research sites
To examine whether the key wheat research
sites used by the National Wheat Research Program
of Ethiopia are representative of wheat production
areas in E[i..i.,. site similarity analyses were
conducted for eight locations (Table 2). The sites
were found to cover a wide range of environments
(Map 7). Almost as important, the zones showed
little or no overlap, suggesting that the set of
research sites ef-...-i 1.:; samples the current wheat
production area.











The area of wheat production identified as "20
km west of Weldiya" (Map 7) in Welo zone of the
Amhara Region is (.,! ... not served by a wheat
research station. Consultation with agronomists
familiar with the region confirmed that a limited
amount of wheat research is conducted on -:;.,i
of the National Wheat Research Program by crop
scientists based at Sirinka, a sorghum research station
situated in a -.i: bottom at an .-.11 .-:., too low
for wheat (ca. 1,850 m). It was also reported that,
to address this deficiency, the Sirinka development
plan includes the establishment of substations in the
neighboring wheat production areas.
The ranges of precipitation, PET, and temperature
limits used in these similarity analyses (+/- 50 mm
and +/- 1 C) merit examination. The intention was to
use a range ,..... .... .!:.I to yield differences that
are detectable in field trials. For potential grain yield


levels of 3,000 to 4,000 .'-,.i, this might represent
a yield difference of 300 kg/ha. Using 10 years of
weather data at Kulumsa, simulations were run to
evaluate wheat yield response to precipitation and
temperature (Fig. 3). Reducing precipitation from the
mean of 540 mm to 490 mm over the ci. I.i
season decreased yields 430 kg/ha, whereas an
increase of 50 mm raised yields 345 kg/ha (Fig. 3A).
Reducing the maximum and minimum temperatures
during the growing season 1 C (for a growing season
mean at Kulumsa of 16 C) increased wheat yields
about 140 kg/ha (Fig. 3B). This was attributable
mainly to a slight delay in maturity (120 days vs. 115
days for the actual -.I-: :.). Increasing temperatures
1C decreased wheat yields 130 kg/ha, whereas an
increase of 2C reduced wheat yields 270 kg/ha.
These simulated results suggest that the limits used to
define site similarity zones are probably conservative.


Figure 3. Variation in wheat grain yield at Kulumsa, Ethiopia, as simulated for changes in growing
season total precipitation (A) and mean temperature (B).


6000


5000


- 4000

-
" 3000-


. 2000-


1000.


200 300 400 500 600 700
Precipitation (mm)


6500

5000

4500
e-
S4000
-^

S3500

>' 3000

2500.

2000.

*1 r /\


S-


15.2 15.6 16 16.4 16.8 17.2 17.6 1E
Temperature (oC)


t Broken lines indicate +/- 2 standard deviations for simulations based on 10 years of weather data.
The vertical lines indicate mean values over the growing season.




--------------------------0


/ j ~-r


/



I/
I/
/'
j;










Conclusions


Because the Kulumsa research station is a
center of ..-::.- for bread wheat research
in Eastern Africa and collaborates with other
national wheat research programs in the Eastern
and Central Africa Maize and Wheat Research
Network (ECAMAW), the similarity of its climate
to other sites in Eastern Africa was also
considered. A less restrictive set of criteria were
used for this exercise (i.e., +/- 20% of n.i -ii
and potential evapotranspiration and +/- 10%
of mean maximum and minimum temperatures),
given that the goals for transnational c. i -: -. -
research should be broader than those for a
sub-national research program. Furthermore, to
better compare Kulumsa conditions with those
of wheat production zones elsewhere in sub-
Saharan Africa, the five optimal months where
P/PE is greater than 0.5 were considered. The
results suggest that the climate at Kulumsa is
similar to conditions in major wheat-producing
areas of Kenya and Ethiopia, and : i,.:.. ,!:.
congruent with those of wheat-producing areas
in the Great Lakes Region ( -- .. .-;.
Uganda, and the North Kivu district of the
Democratic Republic of the Congo), northern
Tanzania, Lesotho, and South Africa (Map 8).
Of these areas, the only one not recognized
as significant for wheat production is the area
in South Africa and east of Lesotho. Wheat is
.. !.i ', not grown in this area due to several
factors, including the difficult terrain, competition
from traditional -..--,-.i-, i ,- crops, and the
comparative advantage for the production of
wheat as a winter crop in the Mediterranean
climate of southwestern South Africa.


Our climate-based analyses suggest that the
greatest opportunity for expanding wheat production
area in Ethiopia would involve increasing the tolerance
of wheat to warmer growing conditions; this means
both heat tolerance and resistance to pathogens and
pests of warmer climates. However, any plans for
expanding wheat production must also consider other
factors, including the adaptation of current and/or
alternate crops, : .ii land-use : i lIII: and market
constraints. The similarity analyses further suggest
that the current distribution of wheat research sites
in Ethiopia provides a reasonable coverage of the
traditional wheat production area in terms of climate
conditions, and support the relevance of the Kulumsa
station for wheat research :I .: jhout much of
Eastern and -,.t ,..-: Africa. Overall, these results
demonstrate the utility of analyzing regional variation
in climate using tools such as those provided in the
!!... i Country Almanac.


Acknowledgments


Drs. Bedada Girma, Amanuel Gorfu, and Kidane
Georgis of EARO and Doug Clements of CIDA/
PSU-I- .: i.: provided valuable information on the
relative importance of wheat in various regions
of Ethiopia. Adriana -. ....J.- and Dave Hodson
helped .; .,-..,.r i in processing the spatial data.
CIMMYT science writer Mike Listman and designer
Wenceslao Almazan ( ii .i .: i to edit and produce
the publication. The -..,ti-,-:- express their gratitude
to the Environmental Systems Research Institute, Inc.,
for providing the Arcinfo and ArcView software. The
authors also appreciate the financial support provided
by the CIMMY: i: -A Eastern Africa Cereals Program
to cover the cost of publishing i .:. document.










Conclusions


Because the Kulumsa research station is a
center of ..-::.- for bread wheat research
in Eastern Africa and collaborates with other
national wheat research programs in the Eastern
and Central Africa Maize and Wheat Research
Network (ECAMAW), the similarity of its climate
to other sites in Eastern Africa was also
considered. A less restrictive set of criteria were
used for this exercise (i.e., +/- 20% of n.i -ii
and potential evapotranspiration and +/- 10%
of mean maximum and minimum temperatures),
given that the goals for transnational c. i -: -. -
research should be broader than those for a
sub-national research program. Furthermore, to
better compare Kulumsa conditions with those
of wheat production zones elsewhere in sub-
Saharan Africa, the five optimal months where
P/PE is greater than 0.5 were considered. The
results suggest that the climate at Kulumsa is
similar to conditions in major wheat-producing
areas of Kenya and Ethiopia, and : i,.:.. ,!:.
congruent with those of wheat-producing areas
in the Great Lakes Region ( -- .. .-;.
Uganda, and the North Kivu district of the
Democratic Republic of the Congo), northern
Tanzania, Lesotho, and South Africa (Map 8).
Of these areas, the only one not recognized
as significant for wheat production is the area
in South Africa and east of Lesotho. Wheat is
.. !.i ', not grown in this area due to several
factors, including the difficult terrain, competition
from traditional -..--,-.i-, i ,- crops, and the
comparative advantage for the production of
wheat as a winter crop in the Mediterranean
climate of southwestern South Africa.


Our climate-based analyses suggest that the
greatest opportunity for expanding wheat production
area in Ethiopia would involve increasing the tolerance
of wheat to warmer growing conditions; this means
both heat tolerance and resistance to pathogens and
pests of warmer climates. However, any plans for
expanding wheat production must also consider other
factors, including the adaptation of current and/or
alternate crops, : .ii land-use : i lIII: and market
constraints. The similarity analyses further suggest
that the current distribution of wheat research sites
in Ethiopia provides a reasonable coverage of the
traditional wheat production area in terms of climate
conditions, and support the relevance of the Kulumsa
station for wheat research :I .: jhout much of
Eastern and -,.t ,..-: Africa. Overall, these results
demonstrate the utility of analyzing regional variation
in climate using tools such as those provided in the
!!... i Country Almanac.


Acknowledgments


Drs. Bedada Girma, Amanuel Gorfu, and Kidane
Georgis of EARO and Doug Clements of CIDA/
PSU-I- .: i.: provided valuable information on the
relative importance of wheat in various regions
of Ethiopia. Adriana -. ....J.- and Dave Hodson
helped .; .,-..,.r i in processing the spatial data.
CIMMYT science writer Mike Listman and designer
Wenceslao Almazan ( ii .i .: i to edit and produce
the publication. The -..,ti-,-:- express their gratitude
to the Environmental Systems Research Institute, Inc.,
for providing the Arcinfo and ArcView software. The
authors also appreciate the financial support provided
by the CIMMY: i: -A Eastern Africa Cereals Program
to cover the cost of publishing i .:. document.











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Map 1. Approximate distribution
of traditional wheat production
areas of Ethiopia and the location
of sites mentioned in this paper
(re-drawn from Belay et al., 1999).


400 0 400 800 Kilometers
,


Map 2. Approximate distribution of
traditional wheat production areas (line
figures) of Ethiopia superimposed on
climatic zones of Ethiopia where
precipitation is over 350 mm and the
mean minimum temperature is between
60 and 110C during the wettest quarter
Sof the year (shaded areas). The darkest
Sfareas in the southwest have a growing
SI season greater than 9 months, based on
P/PE greater than 0.5.




4'afs7

\ ,0s-.y l/ '









Map 3. Areas of Ethiopia where
precipitation is over 350 mm, the
mean minimum temperature is
between 60 and 110C during the
wettest quarter of the year, and
the growing season is 9 months or
less. The vertically hatched zones
represent elevations above 2000 m.




















Map 4. Approximate distribution
of traditional wheat production
areas of Ethiopia re-drawn from
Belay et al. (1999), the proposed
climate-based wheat zone, and 180
wheat germplasm collection sites
(the dots).


0














Map 8. Areas in sub-Saharan Africa having climatic conditions during the optimal five-month
growing season that are similar to those at Kulumsa, Ethiopia.




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