A Research ProposalSubmitted 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

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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

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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

1. Background: Why This Study?- Jamaican Agriculture is Very Sensitive to Climate

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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

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

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1. Background- Sweet potato Production in Jamaica

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

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1. Background- But …Climate Sensitivity not captured by data ‘measurement’ regime

Annual drought index (SPI-12) versus mean annual Sweet potato yields (detrended) for Jamaica 1961-2009) Source: FAOSTAT; Climate Studies Group, Mona

1961196419681972197619801984198719911995199920032007

-3

-2

-1

0

1

2

3

-3

-2

-1

0

1

2

3

4

SPI-12 Detrended Yield

SP

I-12

Yie

ld (

t/ha)

Annual drought index (SPI-12) versus mean annual Sweet potato yields for Jamaica (1961-2009)

Source: FAOSTAT; Climate Studies Group, Mona

1961196519691973197719811985198919931997200120052009

-3

-2

-1

0

1

2

3

0

2

4

6

8

10

12

14

16

18

SPI-12 Yield

SP

I

Yie

ld (

t/ha)

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2. Methodology: Research Design and Tools Summarised

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

Passle

y 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)

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2. Methodology (Analogue Approach): Production in a changing climate

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

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3. Results: Validation of AquaCrop (Devon and Ebony Park)-CC and Biomass

0 14 28 42 56 70 84 98 1121261400

20

40

60

80

100

Devon, Manchester: Rain-fed (2013)

Simulated Measured

DAP

Canopy C

over

(%)

0 13 26 39 52 65 78 91 1041171301430

6

12

18

24

Simulated Measured

DAP

Bio

mass (

t/ha)

0 7 142128354249566370778491980

20

40

60

80

100

Ebony Park, Clarendon-Irrg. (2013)

Simulated Measured

DAP

Can

op

y C

over

(%)

0 7 142128354249566370778491980

8

16

24

32

Simulated Measured

DAP

Bio

mass (

t/ha)

• 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

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3. Results: Validation of AquaCrop (Devon)-Yields

•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

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3. Results: Climate change and Future Production (Relative to baseline)

Present 2030-A2 2030-B2 2050-A2 2050-B2

-15

-10

-5

0

5

10

15

20

25

Yield Changes in Warm & Dry Climate

Rainfed Irrigated

% Y

ield

Cha

nge

Warm & dry climate: less favourable to productionIncreased CO2 enhances yield (Irrigated & Rainfed)

Present 2030-A2 2030-B2 2050-A2 2050-B20

5

10

15

20

25

30

Rainfed Irrigated

% Y

ield

Cha

nge

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

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4. Conclusion: Being Climate Smart about varietal selections

IrrigationRainfall

High Medium Low

HighGanja/

Fire on LandGanja / Fire

on LandClarendon /

Ganja

Medium Ganja Uplifta Ganja

Low GanjaYellow 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

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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

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THANK YOU

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