Background: Climate Sensitivity of Agriculture Importance or Root Crops to Jamaican Food Security Estimating Yields (Manually)- Yield vs. Climate Dilemma Methodology: Tools and Approaches Results: Parameterization, Future Production under Climate Change Conclusions: Climate Smart Implications & Main lessons learnt

1. A Research Proposal
Submitted in Partial-fulfilment of the Requirement for the
Degree of Master of Philosophy in Physics
Collaborators:
Co: Authors:, Michael A. Taylor, Jane E. Cohen, Andre D. Coy, Tannecia S. Stephenson, and Leslie A. Simpson
CLIMATE CHANGE AND FUTURE FOOD SECURITY:
THE IMPACTS ON ROOT AND TUBER CROPS
Presenter: Dale Rankine, CIMH, Barbados

2. Outline of Presentation
1. Background:
 Climate Sensitivity of Agriculture
 Importance or Root Crops to Jamaican Food Security
 Estimating Yields (Manually)- Yield vs. Climate Dilemma
2. Methodology: Tools and Approaches
3. Results: Parameterization, Future Production under Climate Change
4. Conclusions: Climate Smart Implications & Main lessons learnt
2

3. Agriculture very Climate Sensitive
Jamaica (Caribbean) rainfall is bimodal
with Dec-April Dry season
Timing, intensity of Mid-summer drought
affects cropping season
Limited use of irrigation for drought
mitigation
Pattern of mean monthly rainfall in the Caribbean.
Source: ntsavanna.com
3
1. Background: Why This Study?- Jamaican Agriculture is Very
Sensitive to Climate

4.  Sweet potato, Ipomoea batatas (L.), is a 5-month root crop, a dicotyledonous
herbaceous trailing vine and the only economically important member of the family
Convolvulaceae.
 The crop is propagated from cuttings sown during the period September to December.
 The crop rainfall requirement is 750-1250 mm; of this, about 500 mm should occur
during the first third of the crop life. Comparatively lower water requirements than for
other crops
 Sweet potato is drought tolerant but…Crop most sensitive to dry conditions at the
tuber initiation stage (about 40-50 days after planting) (CARDI 2010; Stathers et al.
2013).
 Central to pursuit of reducing imports of, and reliance on, externally grown wheat and
cereals
4
Sweet potato :
• the 6th most
important
crop globally
after RWPMC
• 3rd most
widely grown
root crop in
Jamaica
• More
nutritious
than most
1. Background: Root Crops are Important to Jamaican Agriculture

5. 1. Background- Sweet potato Production in Jamaica
5
Aggregate production of sweet potato for Jamaica (1961-2010). Linear trend line shows increasing
production over the period
Data Source: FAOSTAT, 2012
• General Increase in
production (1961-
2010)
• Mean Production
22,100 tonnes
• Jamaica accounts for
up to 66% of regional
consumption
• Only country in
CARICOM that exports
(UK) consistently

6. 1. Background- But …Climate Sensitivity not captured by data ‘measurement’
regime
6
Annual drought index (SPI-12) versus mean annual Sweet potato yields
(detrended) for Jamaica 1961-2009)
Source: FAOSTAT; Climate Studies Group, Mona
-3
-2
-1
0
1
2
3
4
-3
-2
-1
0
1
2
3
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
Yield(t/ha)
SPI-12
SPI-12 Detrended Yield
Annual drought index (SPI-12) versus mean annual Sweet potato
yields for Jamaica (1961-2009)
Source: FAOSTAT; Climate Studies Group, Mona
0
2
4
6
8
10
12
14
16
18
-3
-2
-1
0
1
2
3
1961
1963
1965
1967
1969
1971
1974
1976
1978
1980
1982
1984
1987
1989
1991
1993
1995
1997
2000
2002
2004
2006
2008
Yield(t/ha)
SPI
SPI-12 Yield

7. 2. Methodology: Research Design and Tools Summarised
7
AquaCrop Model Explained
• B = WP x ΣTr [Biomass]
• ET = E +Tr
• WP normalised for ET and CO2
• Y = B x HI [Yield]
•Robust, Accurate yet Simple
Devon
Ebony
Park
Passley
Gardens
Bodles
*
* *
* On site weather
station
5 Varieties arranged in RCB design
Parameters:
•Rainfall
•Temperature
•Relative Humidity
•Solar Radiation
•Wind
•ETo
Canopy cover, Biomass (above & below)

8. 2. Methodology (Analogue Approach): Production in a changing climate
8
a.
• There is incongruence between the scale at which climate and crop models
operate.
• Climate Models: 25km resolution (Regional Models); Crop models: location
specific, few hectares.
• Climate projections from regional (and global) climate models cannot be directly
applied to crop models - data (even PRECIS) not representative.
• Analogue data (1996-2010: NMIA) used to create two future: climates
*Cool and Wet
*Warm and Dry

9. 3. Results: Validation of AquaCrop (Devon and Ebony Park)-CC and Biomass
9
0
20
40
60
80
100
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
CanopyCover(%)
DAP
Devon, Manchester: Rain-fed (2013)
Simulated Measured
0
6
12
18
24
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
Biomass(t/ha)
DAP
Simulated Measured
0
20
40
60
80
100
0 10 20 30 40 50 60 70 80 90 100
CanopyCover(%)
DAP
Ebony Park, Clarendon-Irrg. (2013)
Simulated Measured
0
8
16
24
32
0 10 20 30 40 50 60 70 80 90 100
Biomass(t/ha)
DAP
Simulated Measured
• Parameterization of Sweet potato in
AquaCrop - original contribution
• Excellent agreement between
simulated and measured canopy cover
(CC)
• Model exhibits good skill in the
simulation of biomass at both locations
and for the two treatments
• When CC is well simulated, so also is
Biomass

10. 3. Results: Validation of AquaCrop (Devon)-Yields
10
•Yield simulation: fairly good; and best for
rain-fed treatment at Devon, Manchester
•Irrigation does not always enhance yields
Simulated (line) versus measured (filled circles) yield of sweet potato
for rain-fed and irrigated treatments at Devon, Manchester (2013).
Error bars represent one standard deviation above and below the
mean

11. 3. Results: Climate change and Future Production (Relative to baseline)
11
-15
-10
-5
0
5
10
15
20
25
Present 2030-A2 2030-B2 2050-A2 2050-B2
%YieldChange
Yield Changes in Warm & Dry Climate
Rainfed Irrigated
Warm & dry climate: less favourable to production
Increased CO2 enhances yield (Irrigated & Rainfed)
0
5
10
15
20
25
30
Present 2030-A2 2030-B2 2050-A2 2050-B2
%YieldChange
Rainfed Irrigated
Cool & Wet climate: favours production, but
over-irrigation is counter productive
The beneficial effects of elevated CO2 BEGIN TO TAPER OFF in
all scenarios as 2050 is approached

12. 4. Conclusion: Being Climate Smart about varietal selections
12
Irrigation
Rainfall
High Medium Low
High
Ganja/
Fire on Land
Ganja / Fire
on Land
Clarendon /
Ganja
Medium Ganja Uplifta Ganja
Low Ganja
Yellow Belly/
Ganja Ganja
If you knew this, and the forecast
from the Met. Service drought
Map, which variety would you
plant where?
Sweet Potato Varietal Drought Tolerance

13. 4. Conclusion: Main lessons learnt
1. Climate Smart Agriculture can benefit from the adoption of technology (crop models) to
replace (expensive and time consuming) trial and error methods of optimisation.
2. Identified a robust yet simple model that can work with data sparse reality of Caribbean
Agriculture sector- FAO AquaCrop Model
3. Satisfactory parameterization of a highly (yield) variable and difficult research drought
tolerant crop- Sweet Potato. Important for future food security (Jamaica & Wider
Caribbean)
4. Expertise built in crop modelling with opportunities for continued research and wider
collaboration (CARIWIG)
5. Options exists for greater regional partnerships: CIMH (BRCCC Programme), CSGM,
CARDI, CARICOM, CCCCC
13

14. THANK YOU
14
https://docs.google.com/forms/d/1s7IjpqVNJ5mx091G8R3c
5vs--6G7pxLm0c5a89qjtyY/viewform
Please Participate in CIMH’s Online Regional Survey: