ICCT comments on the RTI draft review on 

Jatropha for EPA

Soil Carbon

Papers included in the RTI review

Based on our review, none of the papers referenced in this section on 

changes in soil carbon actually report values of soil carbon stocks or 

accumulation. Reinhardt et al. (2007) discussed carbon accounting but did not 

provide any estimates of changes in soil carbon with Jatropha cultivation. 

Srivastrava et al. (2011) reported on soil carbon concentrations on several 

Jatropha plantations (p3939). They did not report on changes in soil carbon 

concentration over time or compare to soil carbon on land other than Jatropha 

plantations. This paper did not provide estimates of soil bulk density, so it would 

not even be possible to calculate soil carbon stocks (t soil C ha-1) from this paper. 

Axelsson & Franzen (2010; p45) provide estimates of carbon stocks on Jatropha 

plantations but do not provide estimates of soil carbon stocks or changes.

Additional papers that were not included

Ogunwale et al. (2008) estimated that Jatropha cultivation on degraded land in 

India could increase soil carbon concentration by 1.33 gC kg-1 (note: this cannot 

be extrapolated to area-based increases in carbon stocks without bulk density 

measurements). Wani et al. (2012) showed that the soil carbon concentration 

was higher on a Jatropha field (on agricultural land and on degraded land in 

India) than a grassland. These studies suggest that Jatropha may sequester 

carbon on some soils.

Biomass carbon

Papers included in the RTI review

Skutsch et al. (2011) did estimate carbon stocks on Jatropha plantations but 

reported numbers that are different from those quoted in the RTI review. RTI 

writes: “In Mexico jatropha plantations were estimated to have a biomass carbon 

stock of 1.6 tons of CO2e per acre (moderate assumption) or 4.04 tons of CO2e 

per acre (optimal assumption) by the tenth year assuming no pruning had taken 

place (Skutsch et al. 2011).” In fact, Skutsch et al. (2011) actually writes on page 

11: “Assuming a steady growth rate (the correlation between age and weight 

was strong, r2 = 0.80) and a planting density of 1600 per hectare, which is the 
standard used in the Mexican jatropha program, this would imply carbon stocks 

of 10 and 4 tons per hectare for fast and moderate-growth, respectively, after 10 

years (Table 4).” This converts to 14.7 – 36.7 tCO2 ha-1. It should be noted that 

the “optimal assumption” appears to refer to Jatropha grown on prime 

agricultural land, and that these are rough estimates relying on assumptions.

This review also cited Achten (2010) for finding that the average biomass carbon 

stock on Jatropha plantations was equivalent to that on grassland. While this is 

true, Achten’s calculations rely partly on shaky estimates from other papers 

(Appendix 4, pLXVIII). Achten starts with a figure of 18.3 tCO2 ha-1 (5 tC ha-1) for 

3.5 year-old Jatropha plantations from Reinhardt et al. (2008). He then applies 

sequestration rates quoted from Henning (in Benge, 2006) and calculated from 

Francis et al. (2005) for plant ages 1-5 years and 5-10 years respectively, and 

then guesses what the sequestration rate would be for plants ages 10-20 years. 

He then takes an average of carbon stocks across the different age groups. It 

should be noted that the Henning estimate is an industry-provided estimate that 

Benge stipulated was likely “extremely high” (Benge, 2006; p16). Achten

calculated a sequestration rate from Francis et al. (2005; p21) based on 

estimates of the total area that could be used for Jatropha cultivation and of the 

total CO2 sequestration that could be expected from cultivating this area – these 

estimates were uncited and not explained in the text. Because most of these 

extrapolations are not based on real data, we advise that the estimate in Achten 

(2010) not be included in this review.

We presume that the reference to biomass yields of 5,000 t ha-1 cited to Hou et 

al. is marked with the wrong units. 

Additional papers that were not included

Here are literature estimates of carbon stocks in Jatropha biomass that we were 

able to find, but we do not necessarily recommend that they be included in the 

review.

Reinhardt et al. (2008) was included in the RTI review but not for biomass 

carbon stocks. Based on figures from CSMCRI (2007; we were unable to access 

this publication), they calculated that 3.5 year-old Jatropha plants had an 

average carbon stock (above- and below-ground biomass) of 5 tC ha-1 (18.4 

tCO2 ha-1). The type of land and location are not given.

As mentioned above, Axelsson & Franzen (2010) was also included in the RTI 

review, but not for biomass carbon stocks. In fact, they do provide estimates of 

carbon stocks in Jatropha biomass of 1.07 – 5.03 tC ha-1 (3.9 – 18.5 tCO2 ha1)

for 5-year-old plants in Egypt and India (p45-46). It should be noted that these 

estimates are based on interviews with government officials and on unspecified 

literature research (p23).

Struijs (2008) estimated biomass stocks of 39.6 tC ha-1 (145.1 tCO2 ha1) for 6-

year-old plants in Tanzania (p28). This estimate was based on an 

unsubstantiated assumption of growth rates coupled with visual inspection of a 

plantation (p23).
Land use competition

Skutsh et al. (2011) is included in the RTI review but not for land use competition. In 

fact, they report that farmers in Mexico have been converting agricultural land 

previously used for maize, other food crops, and pasture (p6).