Modelling soil organic carbon changes under different maize cropping scenarios for cellulosic ethanol in Europe

The utilization of crop residues in the production of second generation biofuels has the potential to boost the bioenergy sector without affecting food commodity prices. However, policies leading to large-scale biomass removal should carefully balance the consequences, both environmental and in terms of emissions, on soil organic carbon (SOC) stocks depletion. Using a recently developed simulation platform, SOC changes were estimated at European level (EU + candidate and potential candidate countries) under two scenarios of low (R30) and high (R90) maize stover removal for cellulosic ethanol production (i.e. 30% and 90% of stover removal, respectively). Additionally, mitigation practices for SOC preservation, namely the introduction of a ryegrass cover crop (R90_C) and biodigestate return to soil (R90_B), were explored under the highest rate of stover removal. The results showed that 15.3 to 50.6 Mt yr-1 of stover (dry matter) would be potentially available for ethanol production under the lower and high removal rates considered. However, large-scale exploitation of maize residues will lead to a SOC depletion corresponding to 39.7 – 135.4 Mt CO2 eq. by 2020 (under R30 and R90, respectively) with greater losses in the long-term. In particular, every tonne of C residue converted to bioethanol was predicted to have an additional impact on SOC loss almost ranging from 0.2-0.5 CO2 eq ha-1 yr-1, considering a continuous biofuel scenario by 2050. The mitigation practices evaluated could more than halve SOC losses compared to R90, but not totally offsetting the negative soil C balance. There is a pressing need to design policies at EU level for optimum maize biofuel cultivations that will preserve the current SOC stock or even generate C credits.

LUGATO Emanuele;  JONES Arwyn; 

2015-03-12

SPRINGER

JRC83895

1939-1234,   

http://link.springer.com/article/10.1007%2Fs12155-014-9529-2,    https://publications.jrc.ec.europa.eu/repository/handle/JRC83895,   

10.1007/s12155-014-9529-2,