Livelihoods and adaptation to
climatic stress in the semi-arid zone
in Tanzania
- A case study of the role of crop diversity and seed
systems
SoCoCA Workshop, CIENS Oslo, Norway, March 19-20, 2013
Ola Tveitereid Westengen
Objective
• Determine the role of maize and sorghum crop
diversity and seed systems for adaptation in an area
currently experiencing climatic stress and where CC
is projections for crop production are negative.
Laikala
Mangae
Projections:
• Regional scale: Projected 22% and 17% yield loss
for maize and sorghum, respectively, in sub-Saharan
Africa by 2050 (Schlenker and Lobell 2010)
• Local scale: More than 20% yield loss for maize in
semiarid regions in Tanzania (Thornton et al. 2009).
• Switching crop species or variety is one of the most
important adaptation measures mentioned both in
the impact literature (Easterling et al. IPCC 2007)
and in the vulnerability oriented adaptation literature
(Adger et al. IPCC 2007) –but different focus.
Adressing a research gap:
«Many broad-scale analyses identify
regions and crops that will be sensitive to
progressive climate change (…), but there is
sparse scientific knowledge as to how
current farming systems can adapt, and
which current farming systems and
agricultural practices will enable
adaptation.»
Options for support to agriculture and food security under climate change,
Vermeulen et al. Environmental Science and Policy 15 (2012) 136-144
Laikala
Mangae
Current
conditions
Mean
1950-2000
2050
projection
Median
value
from
3 GCM
AR4 x
2 SRES
scenarios
Growing season
Lean season
Data source: http://www.ccafs-climate.org/
Projected yield impacts by 2050 -maize
Data source: Thornton et al. 2009. GEC.
CERES-Maize model
Theoretical framework:
Livelihood
approach
Seed System
approach
Data sources:
• Structured and open-ended questionnaire
survey (N=321 HHs in two villages)
• Interviews with formal sector representatives
(breeders etc.)
• Interviews with farmer groups and key
informants on village level
• Seed type categorization
Climatic stress (N=321)
Coping strategies in times of stress
Switch cropping area
Switch to drought tolerant variety
Shift planting dates
Switch to drought tolerant species
Diversify crops
Extend farmland
Diversify livestock
Soil management
Agroforestry
Rainwater harvesting
Food from relief
Cut back on no of meals
Incur debt
Use informal community support
Wage work
Remittances
Business
Artisanal work*
Seasonal migration as farm labour
Sale of possesions
Use formal village support
Technican
Seasonal migration in dry season
Charcoal making
Distress migration
Traditional medicine
Farmland pledging
Professional employment
Sale of productive assets
Harvest wild food
On-farm
Non-farm
Due to climatic stress
Due to other stress factors
0
50
100
150
No of HHs
200
250
300
Crop adaptation modelling
Outcome variable
A6
Switch to drought
tolerant variety
A5
Switch to drought
tolerant species
A7
Diversify
cropping
A12
Extend farmland
Gender of HH head
-3.489e-02
-9.470e-02
-4.035e-01
6.545e-01 *
9.329e-01 **
8.145e-01 **
Age of HH head
-2.961e-03
-1.244e-03
-8.348e-03
-6.811e-03
-2.073e-03
-6.419e-03
Education
-2.739e-01
1.001e-01
-1.753e-01
9.645e-02
-9.479e-02
4.804e-01
HH size
-9.705e-03
4.775e-02
2.682e-02
-1.095e-02
1.589e-01 **
1.203e-02
Livestock ownership
7.656e-01 *
1.037e+00 **
1.069e-01
2.780e-01
2.520e+00
***
Income
1.925e-08
8.799e-11
5.494e-08
7.887e-08
7.698e-08
-2.906e-08
Extension
8.177e-01 **
2.184e-01
8.109e-02
6.252e-01 *
-1.855e-01
2.388e-03
Village effect
-6.596e-01 *
8.010e-01 **
5.785e-01*
2.861e-02
9.071e-01 **
7.638e-01 **
Wald test:
P = 0.011
P = 8.8e-05
P = 0.017
P = 1.7e-13
A10
Diversify livestock
P = 1.8e-07
A9
Switch area
9.324e-01 *
P = 0.00017
Shift to drought tolerant variety
• Crop adaptation by shifting to drought tolerant
varieties is positively associated with livestock
ownership and receiving government extension
services.
Crop adaption = shift to improved varieties?
• Positive correlation between area planted to
improved variety of maize and switching crop
variety: Spearman’s rho = 0,19 (p<0,001)
• Negative correlation between area planted to
traditional maize varieties:
Spearman’s rho = -0,17 (p<0,01)
• Practicing selection –no significant correlation
Seed Systems
Orange circuit: formal seed system, Blue circuit: informal seed systems
From Sperling 2008
Seed sources in Mangae and Laikala
Crop/(local/improved)
No HH
(N=321)
Seed Source %
Own
Barter
Gift
Local
market
Shop
Government
Other
Formal
%
Informal
%
Maize improved
148
12
6
7
7
22
53
6*
65
29
Maize local
204
49
10
9
25
10
2
3
11
86
Sorghum
Improved
Sorghum local
58
14
5
5
7
7
55
9
61
31
257
52
11
10
14
6
2
6
7
87
Pearl Millet
84
67
11
6
7
6
0
6
6
88
Total Kg
Informal System: Maize 5779 kg, Sorghum 2255 kg
Formal System: Maize 1726 kg, Sorghum 223 kg
Maize –(% of area) and no of HHs cultivating:
Recycled
(15%)
35
Traditional
(41%)
Improved
(44%)
12
7
2
116
15
123
Maize
Variable
Reason for
growing
Area
Production
Consumption
Traditional Improved
Mean
Mean
(n=156)
(n=189)
Recycled
Mean
(n=60)
Analysis of deviance
Chi-square test TradImp
Drought resistance (R1)
(1 if major reason, 0 if
not)
Yield (R2)
Taste (R3)
Biotic stress resistance
(R4)
Government directive
(R5)
Acres (continuous)
0,57
0,41
0,46
0.01561 *
0,52
0,14
0
0,53
0,05
0,01
0,71
0,09
0
0.71388
0.55608
0,01
0,19
0
0.04448 *
3,73
3,27
3,36
0.01162 *
Maturity (1<90 days,
2=100-120, 3>120)
Drought resistance
(1=very good, 2=good,
3=not good)
Storability (1=good, 2=ok,
3=not good)
Tastiness
(1=good, 2=ok, 3=not so
tasty)
1,97
1,31
1,34
1,94
1,96
1,77
0.64373
1,26
1,24
1,22
0.31150
1,02
1,08
1,07
0.16329
6.407e-06 ***
Sorghum
Improved
(7%)
Recycled
(2%)
1
8
6
47
213
Traditional
(90%)
Selected results
• For both maize and sorghum «drought
resistance» is the most cited reason for
cultivating the crop.
• Drought resistance is more frequently
reported as reason for growing traditional
varieties than for growing improved varieties.
• Maturity period is longer for traditional than
for improved varieties
Conclusions
• Crop adaptation by shifting varieties is
positively associated by having access to
extension service and improved varieties.
• Households’ continue to use traditional
varieties, recycle improved varieties and allow
genetic introgression between varieties and
practice seed selection.
• Traits beyond mere short duration or drought
escaping is required from improved varieties.
• Households draw on a diverse portfolio of
genetic resources and practices to adapt to
climatic stress.
Thanks to the people in Mangae
and Laikala, to key informants,
to partners at Sokoine
University and field assistants.
Asante sana!