jatropha curcas : assessing the potential water resource

Jatropha curcas: Assessing

the potential water resource

impacts of large-scale

production in South Africa

Mark Gush (CSIR)

Colin Everson (CSIR)

Lelethu Sinuka (CSIR)

• Background: Agro-fuels & Jatropha research

• Jatropha curcas: Description & SA situation

• Why research water resource impacts?

• First project: Sap flow (transpiration) measurements

• Second project: Water-use & growth trial

• Modelling: Needs, strengths & shortcomings

• Implications, conclusions & way forward

Presentation Overview

© CSIR 2010 www.csir.co.za


Background

•Oil crisis, resultant agro-fuel initiatives, SA biofuel strategy

•Motivation: Energy security, business opportunities, rural upliftment / poverty alleviation, env. benefits (renewable, cleaner).

•Environmental impacts unknown (water use, invasiveness, yield).

•Resultant planting of large areas of Jatropha in Asia, Africa and America. However little scientific substance to many of the claims made about Jatropha.

•Global attention on bio-fuels and the potential for Jatropha to produce biodiesel from marginal land with low inputs has created a hype of attention

•No information worldwide on water-use aspects.


Jatropha curcas

• Description

– Semi-deciduous (water stress), monoecious, small tree (<6m tall)

– Fruits with 3 seeds after de-husking, 35% oil, nitrogen-rich press-cake

– Seeds toxic to humans & animals (some non-toxic varieties)

– Stem exudes milky latex, often multi-stemmed

• Bio-physical Requirements

– Rainfall (250–1200mm MAP), drought resistant but affects yield

– Needs warm temperatures (20-28°C MAT), frost sensitive

– Tolerates marginal soils (well drained), mulching beneficial

• Uses

– Fuel and energy (Biodiesel, lamps, stoves?), Cosmetic (soap production), Medicinal, Environmental / Agricultural (erosion control, living hedge, fertilizer)

• Origins and Distribution

– Euphorbiaceae family, originally central America / Mexico, now pan-tropical (Africa, Asia)

– Limited RSA distribution, mainly KZN north coast, seed from Zimbabwe

• Low water-use

• Growth on marginal and degraded lands

• Potential energy crop – high oil yields

• Low maintenance (labour costs)

• Disease tolerance / pest resistance

Jatropha curcas - Claims



• SA Gov. has placed a moratorium on the planting of Jatropha due to fears of:

1. Excessive water use2. Alien invasiveness and3. Lack of knowledge on its’ economic

potential (yield).

• Some aspects are the subject of on-going research by CSIR, UKZN &UP

South African Situation

Should we be concerned about agro-fuels and water-use?


After Berndes (2002). Global Environmental Change 12, 253–271.

Per-capita water withdrawal and availability. Filled dots = 1995.

The two arrows that originate from each dot point to the situation in the year 2075.

Regional water scarcity for 13 countries

400

500

600

700

800

900

1000

1100

1200

1300

1400

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Mean annual precipitation (mm)

Me

an

an

nu

al

ev

ap

otr

an

sp

irati

on

(m

m)

Forest trend

Grassland trend

Zhang et al., 1999

Implications of land-use change


ΔEt ≈ΔStreamflow

• Concept of baseline vegetation.

• DWA stance on bio-fuels water-use (dryland only)


• Aim: To develop predictive capability with respect to the impacts of large-scale planting of Jatropha curcas on water resources in South Africa.

• Methodology: literature review, field measurements and modelling studies.

• Project Duration: Apr 2004 to Mar 2007 (3 yrs)

• Consortium (SDC, CSIR, CPH2O (DHI), Dirk Versfeld cc)

• Funded by the Water Research Commission of South Africa.

Project 1


Potential Growth Area – Jatropha curcas

Jewitt, G.P.W., Wen, H.W., Kunz, R.P. and Van Rooyen, A.M., 2009. Scoping Study on Water Use of Crops/Trees for Biofuels in South Africa. Report to the WATER RESEARCH COMMISSION, WRC Report No. 1772/1/09 (ISBN 978-1-77005-884-2).


OSCA site

MAP = 1016mm

Makhathini site

MAP = 582mm

Research sites – Jatropha curcas water use


4-year old Jatropha curcas trees – OSCA


12-year old Jatropha curcas trees – Makhathini Flats


Heat pulse velocity technique: Sap Flow (water-use)


Results (Makhathini) – HPV DataDaily Transpiration (litres) for 2 Jatropha curcas trees, with Rainfall (Makhathini site)

-50

-40

-30

-20

-10

0

10

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30

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50

60

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90

05-M

ar-

05

19-M

ar-

05

02-A

pr-

05

16-A

pr-

05

30-A

pr-

05

14-M

ay-0

5

28-M

ay-0

5

11-J

un-0

5

25-J

un-0

5

09-J

ul-05

23-J

ul-05

06-A

ug-0

5

20-A

ug-0

5

03-S

ep-0

5

17-S

ep-0

5

01-O

ct-

05

15-O

ct-

05

29-O

ct-

05

12-N

ov-0

5

26-N

ov-0

5

10-D

ec-0

5

24-D

ec-0

5

07-J

an-0

6

21-J

an-0

6

04-F

eb-0

6

18-F

eb-0

6

04-M

ar-

06

18-M

ar-

06

01-A

pr-

06

15-A

pr-

06

29-A

pr-

06

13-M

ay-0

6

27-M

ay-0

6

10-J

un-0

6

24-J

un-0

6

Tra

nsp

irati

on

(li

tres/d

ay)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

110.0

120.0

130.0

140.0

Dail

y R

ain

fall

(m

m)

Rainfall

Transpiration - Tree 1

Transpiration - Tree 2

•Highest daily sap flow = 79.6 litres•Daily Ave = 13.4 litres (over 12-months)

Gush, M.B., 2008. Measurement of water-use by Jatropha curcas L. using the heat-pulse velocity technique. Water SA, Vol. 34, no. 5: 579-583. (ISSN: 0378-4738).


Monthly Totals of Transpiration (mm) for 2 Jatropha curcas trees, with Rainfall (Makhathini)

38.5

23.6

0.8

118.1

54.2

87.1

68.8

26.3

0.5

2.65

.6 15.8

27.83.7 6.4

16.7

-60

-50

-40

-30

-20

-10

0

10

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30

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100

110

Mar-

05

Apr-

05

May-0

5

Jun-0

5

Jul-05

Aug-0

5

Sep-0

5

Oct-

05

Nov-0

5

Dec-0

5

Jan-0

6

Feb-0

6

Mar-

06

Apr-

06

May-0

6

Jun-0

6

Mo

nth

ly T

ran

sp

irati

on

(m

m)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

220.0

240.0

260.0

280.0

300.0

320.0

340.0

Mo

nth

ly R

ain

fall

(m

m)

Rainfall

Transpiration - Tree 1 (mm)

Transpiration - Tree 2 (mm)

Results (Makhathini) – HPV Data

•Single tree totals scaled up to plantation scale•Water use of 12-yr old trees = 350mm (4-year old trees = 144mm)

Gush, M.B., 2008. Measurement of water-use by Jatropha curcas L. using the heat-pulse velocity technique. Water SA, Vol. 34, no. 5: 579-583. (ISSN: 0378-4738).


Results – Jatropha curcas water-use

MarApr

MayJun

JulAug

SepOct

NovDec

JanFeb

0

20

40

60

80

100

120

140

160

Mo

nth

ly E

vap

otr

an

sp

irati

on

& T

ran

sp

irati

on

(m

m)

Month

Reference ETo (Makhathini) Transpiration 4yr old Eucalyptus grandis

Evapotranspiration - grassland Transpiration 12yr old Jatropha curcas

Transpiration 4yr old Jatropha curcas

1328mm

1258mm

695mm

350mm

144mm


• Strong seasonal effect (deciduous nature).

• Good correlations with climate data (air and soil moisture).

• Differences in water use between sites were related to tree age (stem size / leaf area) and water availability (rainfall).

• Water use of Jatropha curcas appears to be low when deciduous.

• Single tree totals scaled up to plantation scale gave the annual water use of 4-year old trees = 144mm and 2-year old trees = 350mm. Less than other vegetation.

Project 1 - Conclusions


• Aim: To measure changes in water-use, growth and yield of a Jatropha curcas / kikuyu agro-forestry system over time.

• Methodology: Establish and maintain a 3ha trial, conduct field measurements and modelling studies, gain practical experience.

• Project Duration: Apr 2004 to present

• Consortium (CSIR, UKZN, UP)

• Funded by the Water Research Commission of South Africa.

Project 2


Total evaporation measurements -Ukulinga Research Farm (UKZN) Pietermaritzburg.

Project 2 - Jatropha grown in a silvopastoral (Kikuyu) agro-forestry system


0

2

4

6

8

En

erg

y f

lux

(m

m)

0

10

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Pre

cip

i ta

tio

n (

mm

)

200 225 250 275 300 325 350 0 25 50 75 100 125 150 175 200

200 225 250 275 300 325 350

20070 25 50 75 100 125 150 175 200

2008

Rn - G

ET-SR

ET-TV

ET-EC

Day of Year

Project 2 – Total evaporation of Jatropha curcas


February 2007

October 2007 - Pruned

Project 2 – Growth (tree height) of Jatropha curcas

February 2005

December 2009

0

25

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Fe

b-0

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Ma

r-05

Apr-

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-05

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l-0

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-05

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-05

Oct-

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v-0

5

Dec-0

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Jan

-06

Fe

b-0

6

Ma

r-06

Apr-

06

May-0

6

Jun

-06

Ju

l-0

6

Aug

-06

Sep

-06

Oct-

06

No

v-0

6

Dec-0

6

Jan

-07

Fe

b-0

7

Ma

r-07

Apr-

07

May-0

7

Jun

-07

Ju

l-0

7

Aug

-07

Date (February 2005 to August 2007)

Tre

e H

eig

ht

(cm

)

Jatropha only

Standard square

Single row

Double row

Triple row


3 m

1.2 m

Project 2 – Competition trials with Jatropha curcas

The final average height of the trees under the different treatments

Gain from control

Treatment Mean ± S.D.

Absolute

(mm)

Relative

(%)

Control 107.28 ±9.16a - -

60 111.95 ±9.27 ab

4.7 4.36

120 115.27 ±13.98 ab

8.0 7.45

300 117.97 ±13.54b 10.7 9.97

a, b: Significantly different groups using Scheffe Post Hoc test (SPSS)


•Harvested part is fruit containing 3 seeds.

•Seeds = 70% of mass (30% is fruit coat).

•Gross energy is 31- 46 MJ kg-1.

Project 2 – Yield (Jatropha curcas as an energy crop)

Effect of Pruning

•Low production figures apply to 1-2 yr old plantations.

•Current reported yields 0.6 to 4.1 t seed ha-1.

•Max 7.8 t projected for mature stands.


Relationship between the mass of Jatropha seeds and the time

to harvest and to dehusk

y = -2.6179x2 + 37.336x + 26.674

R2 = 0.5747

0

20

40

60

80

100

120

140

160

180

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Mass of seed (kg)

Tim

e to h

arv

est (m

ins)

y = -0.942x2 + 140x + 4.5387

R2 = 0.939

0

100

200

300

400

500

600

700

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Mass of seeds (kg)

Tim

e todehusk (m

ins)

Conclusion:

Harvesting will require large labour inputs

Project 2 – Labour costs?


Assumed tolerance based on single trees - does not apply to Jatropha plantations.

In plantations serious problems have been reported with fungi, viruses and attack

by insects. This has also been our experience at Ukulinga

Insect Damage

Fungal Damage

Project 2 – Jatropha curcas tolerance to pests and disease


• Claims of low water use appear to be true. However, water use measurements need to be made in tropical regions where the plant remains green all year.

• High oil yields have not been observed. Major constraint - lack of knowledge under different conditions (marginal vs. fertile)

• Jatropha has potential to be exploited in semi-arid & arid conditions for soil water conservation, erosion control, living fences, green manure, soap production and many others. For these the claims are verifiable.

Project 2 - Conclusions


• Silvicultural practices (limiting competition, mulching, pruning) important for tree production – will effect economic viability.

• Claims of low labour input not true. Problems with mechanical harvesting due to sequential flowering.

• Tolerance to pests and diseases not true in plantations. Increases input costs due to need for insecticides and fungicides.

• No information on alien invasiveness

• Economic viability may be improved by growing in an agro-forestry system.

Project 2 – Conclusions (cont.)


Modelling - Spatial ExtrapolationMonthly P-M ETo

Hallowes, J. 2007. Water use mapping of Jatropha curcas. In: Holl, M., Gush, M.B., Hallowes, J. and Versfeld, D.B. (Eds). 2007. Jatropha curcas in South

Africa: an assessment of its water use and bio-physical potential. WRC Report 1497/1/07, Chapter 5.

X =


Modelling – Temporal Extrapolation

Gush, M.B. and Moodley, M. 2007. Water use assessment of Jatropha curcas. In: Holl, M., Gush, M.B., Hallowes, J. and Versfeld, D.B. (Eds). 2007. Jatropha

curcas in South Africa: an assessment of its water use and bio-physical potential. WRC Report 1497/1/07, Chapter 4.

• Limitations of input data (few measurements)

• Account for varying bio-physical conditions.

• Dry-land water-use of Jatropha curcas is low

• Useful additional information (growth, yield & management) being collected from existing trial

• Calculation of “water footprint” or “virtual water” WUE possible from this kind of study

• Expand concept to bio-fuels water-use atlas (WRC, UKZN, CSIR, UP project - WATER USE OF CROPPING SYSTEMS ADAPTED TO BIO-CLIMATIC REGIONS IN SOUTH AFRICA AND SUITABLE FOR BIO-FUEL PRODUCTION)

• Other environmental issues

General Conclusions & Way Forward


Thank you

•Water Research Commission for funding the projects

•Fellow Project Consortium Members:•Siyaphambili Development Consulting

•CPH20 / DHI•Dirk Versfeld cc.•University of KwaZulu-Natal•University of Pretoria

•CSIR Project Team:•Dr. Michael Mengistu, Mr. Lelethu Sinuka, Mr. Alistair Clulow, Mr. Joshua Xaba

Acknowledgements

jatropha curcas : assessing the potential water resource

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