Soil Carbon Sequestration or Biofuel Production: New Land-Use Opportunities for Mitigating Climate over Abandoned Soviet Farmlands

Abstract

International audienceAlthough the CO(2) mitigation potential of biofuels has been studied by extrapolation of small-scale studies, few estimates exist of the net regional-scale carbon balance implications of biofuel cultivations programs, either growing conventional biofuel crops or applying new advanced technologies. Here we used a spatially distributed process-driven model over the 20 Mha of recently abandoned agricultural lands of the Former Soviet Union to quantify the GHG mitigation by biofuel production from Low Input/High Diversity (LIHD) grass-legume prairies and to compare this GHG mitigation with the one of soil C sequestration as it currently occurs. LIHD has recently received a lot of attention as an emerging opportunity to produce biofuels over marginal lands leading to a good energy efficiency with minimal adverse consequences on food security and ecosystem services. We found that depending on the time horizon over which one seeks to maximize the GHG benefit the optimal time for implementing biofuel production shifts from "never" (short-term horizon) to "as soon as possible" (longer-term horizon). These results highlight the importance of reaching agreement a priori on the target time interval during which biofuels are expected to play a role within the global energy system, to avoid deploying biofuel technology over a time interval for which it has a detrimental impact on the GHG mitigation objective. The window of opportunity for growing LIHD also stresses the need to reduce uncertainties in soil C inputs, turnover, and soil organic matter stability under current and future climate and management practices

Rapid land use change after socio-economic disturbances: the collapse of the Soviet Union versus Chernobyl

“…Forests have regrown on many of the former farm fields, providing ecosystem services such as increased water quality, soil stability, and carbon sequestration, as well as additional habitat for wildlife (Pekarova and Pekar 1996, Tasser et al 2007, Vuichard et al 2009. Both the Chernobyl disaster and the collapse of the Soviet Union thus caused inadvertently a 'rewilding', i.e., the return of semi-natural vegetation across large areas that were previously farmed.…”

Effects of institutional changes on land use: agricultural land abandonment during the transition from state-command to market-driven economies in post-Soviet Eastern Europe

“…Agricultural land abandonment has strong environmental and socio-economic consequences. Reforestation on abandoned agricultural lands can defragment forests, sequester carbon (Smith et al 2007, Vuichard et al 2009 and improve hydrological regimes and water quality (Sileika et al 2006). However, the early successional vegetation that grows on abandoned fields provides fuel for wildfires (Dubinin et al 2010, Lloret et al 2002 and increases the propagule pressure of weeds, pests and pathogens on the remaining agricultural fields (Smelansky 2003).…”

How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

“…The national assessment for biological C sequestration in the USA will be conducted in the course of the next 3-4 years. At the same time, biofuels are being promoted as an important part of the global energy needed to reduce fossil fuels use and to decrease anthropogenic greenhouse gas fluxes (Vuichard et al 2009;Barton et al 2010). Many studies evaluated the C mitigation potentials of biofuels through cultivation technologies and ecological vulnerability (e.g., land use change and biodiversity loss, etc.)…”