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Widely blended in the transportation fuels, biofuels have been generally regarded as indispensable components in the U.S. national energy portfolio. Although the current production of cellulosic biofuels has been staggering at pilot scales, it is expected that large-scale cultivation of cellulosic biofuel crops may occur when techniques for cost-effective bioconversion of lignocellulosic biomass to ethanol are available. However, it is still unclear if enough land is in existence to accommodate potential large-scale lignocellulosic crops development without negative effects on the environment and food market. The appropriate land use for the next-generation biofuel crops should be planned and allocated in a manner that the competitive use of land dedicated to food and energy production and other side effects could be minimized. This research proposes an approach of identifying the potential available land for planting switchgrass in the U.S. Midwest using a GIS-based multi-criteria analysis that combines soil and water constraint factors. The results showed that land areas of approximately 13.6 million ha are unsuitable for profitable food crops but available for switchgrass cultivation in 7 U.S. Great Plains states. The findings can assist decision-makers in formulating land use policies and related environmental management strategies. [ABSTRACT FROM AUTHOR]

The biofuel-related land use in the USA and the EU has significantly expanded during the last decade; models have been used to estimate land availability and demand in these regions. This paper provides an overview of different land-use modeling practices applicable to first- and second-generation biofuels. We review the importance of different land categories for biofuels, modeling approaches (top-down/bottom-up) and their integration, data availability for calibration and validation, model scale, and uncertainty. Possible future changes of biofuel land use and research gaps and limitations are synthesized. Key issues are the lack of data for independent validation and the need for better integration of dynamic bottom-up models into the top-down policy analysis. More research is needed to deal with the large-scale introduction of second-generation biofuel crops required. The paper culminates in describing how models can help to meet the challenge of supplying more fuel from lignocellulosic crops ( LCC) in ways that reduce indirect land-use change ( iLUC) and how such transition could be implemented in policy and practice. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

An integrated assessment of crop-energy-water (CEW) nexus is critical to understand the tradeoffs and synergies for better management of sustainable agricultural systems. In this study, we evaluate the historic evolution of CEW interactions in the Central Valley, California, a critical agricultural region that produces approximately 50% of US fruits, nuts and vegetables. Specifically, we consider three nexus elements, including water use for irrigation (blue water), energy use for groundwater pumping, and crop yield (for all crops aggregated, almond and cotton). To quantify the interactions between CEW elements, we estimate the water use for cropping (water footprint) and energy use for cropping (energy footprint). We conduct the analyses for four historical periods, i.e., 2007–2009 (Drought 1), 2010–2011 (Post-drought 1), 2012–2015 (Drought 2) and 2016–2018 (Post-drought 2). We find that the southern regions (San Joaquin and Tulare) are susceptible to greater stress on energy and water, especially during droughts. The groundwater footprint (GWF) has been continuously increasing due to greater crop water use and a shift from row crops to profitable water-intensive tree crops. The GWF in Tulare during Drought 2 was around 60% higher than Drought 1, where the GWF in Tulare was almost twice that of Sacramento. The energy and water uses for almond production have increased during the recent periods, whereas their uses have mostly decreased for cotton. On average, energy and water footprints under almond crop scenario are around 3–3.5 times as much as the footprints under all crops scenario. [ABSTRACT FROM AUTHOR]