By Abdul Samad Nabizada

1. Crop suitability assessment under
the perspective of climate change:
a case study in Niger
Supervisor:
Prof. Camilla Dibari
Co-Supervisor:
Dr. Sergi Costafreda Aumedes
Prof. Roberto Ferrise
Candidate:
Abdul Samad Nabizada
Scuola di
Agraria

2. Scuola di
Agraria
Introduction
Objectives
Methodology
Results
Conclusions
Outline
1
2
3
4
5

3. Scuola di
Agraria
Agriculture in Niger
o More than 80% of the population of the country engaged
in Agriculture.
o Contribute over 40% to total GDP
o Country is among the top ten countries producing cowpea,
millet, and sorghum in the world
o Since the '60s, cereals, cowpea, and onion production has
strongly increased 530%, 586%, 605%, respectively
(FAOSTAT, 2021)
Introduction

4. Scuola di
Agraria
Climate change in Niger
o Vulnerable African countries to climate change
o Evidencing numerous droughts in the 1960s, 70s, and 80s due to
decreasing rainfall
o An increase in mean annual temperature of +0.6° +0.8°C
observed in the country from 1970 to 2010 (WBG 2016)
o Climate change is estimated to reduce crop yields in Sub-
Saharan West Africa in the future (Kotir 2011, Dale et al. 2017).
Introduction

5. Scuola di
Agraria Objectives
1. Analyze changes in land suitability for main
cultivated crops
a) To model the historical and future land
suitability (integrated GIS-based multi-criteria
decision analysis approach – IAO)
b) Comparing the expected land suitability under
different climate scenarios

6. Scuola di
Agraria Materials and Methods:
Study area
o 23.31 million population
o A total land area of 1.3 M km2, of which 36.7% is an
agricultural area (FAO 2019).
o Average annual temperatures range from 21.9° to
36.4° C
o Precipitation ranges from 100-200 mm in the North
to 500-600mm in the South
Sahara
Sahelo-Sahara
Sahel
Soudan

7. Scuola di
Agraria Materials and Methods:
Data Type Type of
Data
Source
Physical
parameters
Raster Harmonized
World Soil
Database
Chemical
parameters
Raster Harmonized
World Soil
Database
Climate
variables
Raster Worldclim
Crop calendar Periods Country expert and
literatures
Crop
requirement

8. Scuola di
Agraria Materials and Methods:
 More than five GCMs where used (Wang et al.
2020 ) to reduce uncertainty
• CCSM4
• CNRM-CM5
• IPSL-CM5A- LR
• HadGEM2- ES
• MPI-ESM-LR
• NorESM1-M
 Three Representative Concentration Pathway
(RCPs):
• RCP 2.6
• RCP 4.5
• RCP 8.5
 Historical (1970-2000)
 2 different future time slices:
• 2041-2060 (2050)
• 2061-2080 (2070)
Crop
requirement

9. Scuola di
Agraria Materials and Methods:
CROPS CALENDAR
MONTHS Sorghum Millet Cowpea Onion
January - - - G
February - - - G
March - - - H
April - - - -
May S S S -
June S S S -
July G G G -
August G G G S
September G G G G
October H H H G
November - - - P
December - - - G
S=Sowing G=Growing H=Harvesting P=Planting
Crop
requirement

10. Scuola di
Agraria Materials and Methods:
(Source: Sys et al, 1993)
Characteristics S1 S2 S3 N1 N2
100 95 85 60 40 25 0
Precip GS
500-700
500-400
700-900
400-300
900-1200
300-150
1200-1400
-
-
<150
>1400
Mean temp GS 25-24 24-21 21-18 18-15 - <15
Slope (%) 0-1 1-2 2-4 4-6 - >6
pH 6.5-6.0
6.5-7.0
6.0-5.5
7.0-8.2
5.5-5.3
8.3-8.3
5.3-5.2
8.3-8.5
<5.2
-
-
>8.5
Organic C
1.5 1.5-0.8 <0.8 - - -
Ece (dS/m)
0-4 4-8 8-12 12-16 16-20 >20
Base saturation
>50 50-35 35-15 <15 - -
Crop
requirement
Sorghum

11. Scuola di
Agraria Materials and Methods:
Class Description Score
S1 Highly Suitable 0.85-1
S2 Moderately Suitabile 0.60-0.85
S3 Marginally Suitable 0.40-0.60
N1 Currently Not
Suitable
0.25-0.40
N2 Permanently not
Suitable
0-0.25
The FAO Land suitability classes (FAO, 1976, Sys et al., 1993)
Crop
requirement

12. Scuola di
Agraria Materials and Methods:
 Kappa statistic (Cohen, 1960) a statistical analysis
was performed to evaluate the rate of change in the
spatial distribution of suitability classes compared to
the present period. (<0=poor agreement and 0.81 =
1 prefect agreement)
Crop
requirement

13. Scuola di
Agraria Results
Future climatic trends: Mean temp.
30
32
34
36
38
P RE S E NT F UT _2050 F UT _2070
TEMP.
(°C)
30
32
34
36
38
P RE S E NT F UT _2050 F UT _2070
TEMP.
(°C)
30
32
34
36
38
P RE S E NT F UT _2050 F UT _2070
TEMP.
(°C)
2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
RCP 2.6
RCP 4.5
RCP 8.5
Historical Period
1979-2000
2.2 °C 2.7 °C

14. Scuola di
Agraria Results:
Future climatic trends: Mean Precip.
2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
RCP 2.6
RCP 4.5
RCP 8.5
Historical Period
1979-2000
100
120
140
160
180
200
P RE S E NT F UT _2050 F U T _2070
PERCIP.
(MM)
100
120
140
160
180
200
P RE S E NT F U T _2050 F UT _2070
PERCIP.
(MM)
100
120
140
160
180
200
P RE S E NT F UT _2050 F UT _2070
PERCIP.
(MM)
31 mm 25 mm

15. Scuola di
Agraria Results:
Land suitability trend
Sorghum
SORGHUM
SUI.
CLAS
Hist. RCP 2.6 RCP 4.5 RCP 8.5
2050 2070 2050 2070 2050 2070
S1 0.00 0.01 0.01 0.01 0.01 0.01 0.02
S2 0.49 40 39.51 40.31 39.95 40.72 41.2
S3 53.61 50.2 50.30 50.42 50.29 49.52 49.7
N1 34.87 9.66 10.18 9.26 9.75 9.75 8.99
N2 11.04 0.00 0.00 0.00 0.00 0.00 0.00
KAPPA - 0.18 0.18 0.17 0.18 0.17 0.17 2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
Historical Period
1979-2000

16. Scuola di
Agraria Results:
Land suitability trend
Millet
MILLET
SUI.
CLAS
Hist. RCP 2.6 RCP 4.5 RCP 8.5
2050 2070 2050 2070 2050 2070
S1 0.06 0.04 0.04 0.19 0.02 0.02 0.01
S2 66.81 70.04 69.99 88.72 68.16 67.74 66.68
S3 22.11 29.92 29.97 11.08 31.82 32.08 27.67
N1 11.02 0.00 0.00 0.00 0.00 0.16 5.64
N2 0.00 0.00 0.00 0.00 0.00 0.00 0.00
KAPPA - 0.86 0.86 0.87 0.87 0.88 0.94 2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
Historical Period
1979-2000

17. Scuola di
Agraria Results:
Land suitability trend
Cowpea
COWPEA
SUI.
CLAS
Hist. RCP 2.6 RCP 4.5 RCP 8.5
2050 2070 2050 2070 2050 2070
S1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
S2 44.55 44.18 43.90 35.32 28.13 25.58 11.29
S3 44.39 46.54 46.73 54.48 59.74 59.46 61.77
N1 11.06 9.28 9.38 10.19 11.95 13.43 20.18
N2 0.00 0.00 0.00 0.00 0,18 1.53 6.76
KAPPA - 0.68 0.66 0.64 0.63 0.56 0.25 2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
Historical Period
1979-2000

18. Scuola di
Agraria Results:
Land suitability trend
Onion
ONION
SUI.
CLAS
Hist. RCP 2.6 RCP 4.5 RCP 8.5
2050 2070 2050 2070 2050 2070
S1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
S2 43.58 43.35 43.37 39.63 35.65 32.99 25.76
S3 45.35 56.44 56.45 60.12 63.92 66.40 71.61
N1 11.07 0.21 0.18 0.25 0.43 0.60 2.63
N2 0.00 0.00 0.00 0.00 0.00 0.00 0.00
KAPPA - 0.74 0.75 0.74 0.73 0.73 0.72 2041-2060
RCP 2.6
2041-2060
RCP 4.5
2041-2060
RCP 8.5
2061-2080
RCP 2.6
2061-2080
RCP 4.5
2061-2080
RCP 8.5
Historical Period
1979-2000

19. Scuola di
Agraria Conclusions
o Overall, the study found an increase average temperature of
about +2.2 °C and +2.7 °C for both future periods respectively.
o The most suitable crop for the present and future conditions is
millet, with currently about 66.81% of the area considered
moderately suitable.
o Study estimated that the land suitability for sorghum would
increase in class S2 and, decrease in Class N1.
o Decrease in land suitability observed for cowpea in class N2.
o Onion has shown a significant increase in class S3 and decrease
in class S2 and, N1.
Sorghum
Millet
Cowpea
Onion

20. Scuola di
Agraria Conclusions
Strategies for future sustainable land use
Long term
practice
Soil and water
conservation
Encouraging
tree crops
Vegetable
farming
Small
ruminants
Improving
Crop Varieties
Short term
practice
Planting time
Crop
diversification
Mineral
fertilizer
Using
improved
varieties

21. Scuola di
Agraria