Abstract
Increasing global energy demands are leading towards the production of bio-alcohols from food crops, subsequently posing detrimental consequences in terms of food insecurity. Selection of suitable energy crops and availability of land for their cultivation are the leading concerns. Although cellulosic feedstocks are believed to have positive environmental impact and can make up a remarkable proportion of future energy portfolios yet they cannot be produced on arable lands due to social, environmental and economic concerns. A promising alternative is to grow cellulosic crops (traditionally called energy crops) on “marginal lands”. Low productivity and profitability make marginal lands puny for agricultural practices either due to intrinsic climatic limitations or they are susceptible to erosion and other environmental risks. However, marginal lands may be practically suitable either to grow short-rotation grasses or perennial vegetation, native to these lands which are better adapted to poor soils. Energy crops grown on marginal lands will not only provide cellulosic biomass without competition with food crops, but also help to reclaim those lands along with substantial mitigation of greenhouse gases (GHG) without posing any risk of food security. Nonetheless, the user-friendliness of such lands for cellulosic biomass production on commercial scale, and the corresponding GHG emissions, still remain indeterminate. This review describes the potential of marginal lands to produce ample amounts of biomass, also discusses the suitable crops cultivable on marginal lands for energy purpose, management practices of crop production on marginal lands and their economic and environmental perspectives.
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•Ever increasing global energy demands, depleting sources are the driving forces to find alternatives.•Marginal lands offer an opportunity to produce biomass for bioenergy.•Biomass produced on marginal lands cause no competition with land for food crops.•Geographic information system may be applied to locate the global marginal lands.•Detailed characterization of marginal land biomass is required to evaluate their suitability for bioenergy production.