Drivers, Constraints and Trade-Offs Associated with Recultivating Abandoned Cropland in Russia, Ukraine and Kazakhstan

Further cropland expansion might be unavoidable to satisfy the growing demand for land- based products and ecosystem services. A crucial issue is thus to assess the trade-offs between social and ecological impacts and the benefits of converting additional land to cropland. In the former Soviet Union countries, where the transition from state-command to market-driven economies resulted in widespread agricultural land abandonment, cropland expansion may incur relatively low costs, especially compared with tropical regions. Our objectives were to quantify the drivers, constraints and trade-offs associated with recultivating abandoned cropland to assess the potentially available cropland in European Russia, western Siberia, Ukraine and Kazakhstan - the region where the vast majority of post- Soviet cropland abandonment took place. Using spatial panel regressions, we characterized the socio-economic determinants of cropland abandonment and recultivation. We then used recent maps of changes in cropland to 1) spatially characterize the socio-economic, accessibility and soil constraints associated with the recultivation of abandoned croplands and 2) investigate the environmental trade-offs regarding carbon stocks and habitat for biodiversity. Less cropland abandonment and more recultivation after 2000 occurred in areas with an increasing rural population and a younger labor force, but also improved yields. Synergies were observed between cropland recultivation and intensification over the 2000s. From 47.3 million hectares (Mha) of cropland abandoned in 2009, we identified only 8.5 (7.1-17.4) Mha of potentially available cropland with low environmental tradeoffs and low to moderate socio-economic or accessibility constraints that were located on high-quality soils (Chernozems). These areas represented an annual wheat production potential of 14.3 (9.6-19.5) million tons (Mt). Conversely, 8.5 (4.2-12.4) Mha had high carbon or biodiversity trade-offs, of which 10% might be attractive for cropland expansion and thus would require protection from recultivation. Agroenvironmental, accessibility, and socio-economic constraints suggested that the remaining 30.6 (25.7-30.6) Mha of abandoned croplands were unlikely to provide important contributions to future crop production at current wheat prices but could provide various ecosystem services, and some could support extensive livestock production. Political and institutional support could foster recultivation by supporting investments in agriculture and rural demographic revitalization. Reclaiming potentially available cropland in the study region could provide a notable contribution to global grain production, with relatively low environmental trade-offs compared with tropical frontiers, but is not a panacea to address global issues of food security or reduce land-use pressure on tropical ecosystems.