WATER USE AND SUITABILITY OF

JATROPHA CURCAS AS A BIOFUEL

FEEDSTOCKCS Everson1, M Mengistu1 and M Gush2

1Centre for Water Resources Research, UKZN1Centre for Water Resources Research, UKZN2Natural Resources and the Environment, CSIR.

Background

• Since 2005 increasing interest in biofuel

development within southern Africa.

• Key driver potential to boost rural development

and energy security.and energy security.

• Jatropha curcas in particular captured attention

of developers as a wonder biofuel crop with

many projects being established in Mozambique,

Swaziland, Zambia, Tanzania, and Namibia.

Jatropha curcas - Claims

• Low water-use

• Growth on marginal and degraded

lands

• Potential energy crop – high oil • Potential energy crop – high oil

yields after 2-3 yrs.

• Low maintenance (labour costs)

• Disease tolerance / pest resistance

South African Situation

SA in 2007 placed a moratorium

on the planting of Jatropha due

to fears of:1. Excessive water use1. Excessive water use

2. Alien invasiveness and

3. Lack of knowledge on its’

economic potential (yield)

Jatropha curcas – Water use

Should we be concerned about

biofuels and water use?

Regional water scarcity for 13 countries

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.

• Aim: To develop predictive

capability with respect to the

impacts of large-scale planting of

Jatropha curcas on water resources

in South Africa.

First exploratory Research

Mature

© CSIR 2006

www.csir.co.za

Site water balance:

Mature

Jatropha

curcas

Investigation into the impacts of large-scale

planting of Jatropha curcas on water

resources

Daily Transpiration (litre

s) fo

r 2 Jatropha curcas tre

es, w

ith Rainfall (O

SCA site)

0 5

10

15

20

25

30

35

Transpiration (litres/day)

60

75

90

105

120

135

150

165

Daily Rainfall (mm)

Rainfall

Transpiration - T

ree 1

Transpiration - T

ree 2

Re

sults (Z

ulu

lan

d) –

Da

ily T

ran

spira

tion

Da

ta (litre

s)

-20

-15

-10 -5

01-Feb-05

15-Feb-05

01-Mar-05

15-Mar-05

29-Mar-05

12-Apr-05

26-Apr-05

10-May-05

24-May-05

07-Jun-05

21-Jun-05

05-Jul-05

19-Jul-05

02-Aug-05

16-Aug-05

30-Aug-05

13-Sep-05

27-Sep-05

11-Oct-05

25-Oct-05

08-Nov-05

22-Nov-05

06-Dec-05

20-Dec-05

03-Jan-06

17-Jan-06

31-Jan-06

14-Feb-06

28-Feb-06

14-Mar-06

28-Mar-06

11-Apr-06

25-Apr-06

09-May-06

23-May-06

06-Jun-06

20-Jun-06

0 15

30

45

Daily Rainfall (mm)

•Max Trans = 33L.day-1, a

ve tra

ns = 5.3L.day-1

Regional Estimates

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.

water-use of a range of measured vegetation types including

Jatropha curcas (age 4 and 12 yrs), grassland and Eucalyptus

plantations.

100

120

140

160

180

Monthly Evapotranspiration / Transpiration (mm)

Reference ETo (Makhathini)

Transpiration 4yr old Eucalyptus grandis

Evapotranspiration - grassland

Transpiration 12yr old Jatropha curcas

Transpiration 4yr old Jatropha curcas

0

20

40

60

80

100

Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb

Monthly Evapotranspiration / Transpiration (mm)

Compared to the other vegetation types, Jatropha water use was less than for natural

vegetation and significantly below that used by a typical Eucalyptus plantation

Conclusion• In the areas where Jatropha can be planted it is

unlikely to use more water than indigenous

vegetation types.

• It was thus unlikely to have a streamflow reduction

impact as defined by the SA National Water Act of

1998.

Plot studies - Jatropha grown in a silvopastoral (Kikuyu) agro-forestry system

Total evaporation - Ukulinga

Research Farm (UKZN) Pmb.

Total evaporation of Jatropha curcas

February 2007

Growth (tree height) of Jatropha curcas

February 2005

1.25

1.50

1.75

2.00

2.25

2.50

Tree Height (m)

Jatropha only

Standard square

Single row

Double row

Triple row

October 2007 - PrunedDecember 2009

0.00

0.25

0.50

0.75

1.00

Feb-05

Apr-05

Jun-05

Aug-05

Oct-05

Dec-05

Feb-06

Apr-06

Jun-06

Aug-06

Oct-06

Dec-06

Feb-07

Apr-07

Jun-07

Aug-07

Oct-07

Dec-07

Feb-08

Apr-08

Jun-08

Aug-08

Oct-08

Dec-08

Feb-09

Apr-09

Jun-09

Aug-09

Oct-09

Dec-09

Feb-10

Apr-10

Date (February 2005 to April 2010)

Tree Height (m)

Pruning Pruning

Pruning

2007 2008

•Harvested part is fruit containing 3 seeds.

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

•Gross energy is 31- 46 MJ kg-1.

Yield (Jatropha curcas as an energy crop)

•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.

Seed Yield

250

300

350

400

Se

ed

Yie

ld

(kg

ha

-1)

Jatropha only

Single row

Double row

Triple row

Standard square

0

50

100

150

200

250

2005 2006 2007 2008 2009 2010

Se

ed

Yie

ld

(kg

ha

Year

Low labour Cost?Relationship between the mass of Jatropha seeds and the time to

harvest and to dehusk

y = -2.6179x2 + 37.336x + 26.674

R2 = 0.574720

40

60

80

100

120

140

160

180

Time to harvest (mins)

Conclusion:

Harvesting will R2 = 0.5747

0

20

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Mass of seed (kg)

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)

Time todehusk (mins)

Harvesting will

require large

labour inputs

Tolerance to pests and diseasesThe assumed tolerance generally based on singular trees and does not

apply to Jatropha grown in plantations.

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

attack by insects. This has also been our experience at Ukulinga

Fungal Damage

Insect Damage

Conclusions

1. Claims of low water use verified.

2. Claims of low labour input not true. Problems with

mechanical harvesting due to sequential flowering.

3. Tolerance to pests and diseases not true in plantations.

Therefore increasing input costs through a need for

insecticides and fungicides.insecticides and fungicides.

4. No information on alien invasiveness.

5. High yields not observed

The South African results are so unequivocal that J. curcas

under the experimental conditions does not fulfil the

claims that it is a “wonder” biodiesel plant.