416
Such changing agricultural practices could have far-reaching impacts for water
quantity and quality, cascading into long-term effects on crop yield and food security. Consequently, modeling of FEW systems should represent changing bioenergy
land use and its impact on crop distribution and yield.
Growing bioenergy on marginal land in the form of perennial vegetation may
alleviate food-versus-fuel trade-off concerns while reducing the carbon debt and
indirect land-use costs associated with food-based biofuels. However, such expansion could have regional and widespread effects on climate, land, and water, which
must be assessed using an advanced coupled model system.
Thus, FEW system models should address key questions such as: Will largescale deployment of the new generation of heat-resistant, drought-tolerant, or
higher-reflectivity crop hybrids deliver high yields, increase water use efficiency, or
reduce canopy temperatures sufficiently to meet future food demand under available
water supply while maintaining soil and water quality and offsetting greenhouse gas
warming? If not, what will the deficiencies be?
15.3.2 Energy–Water
Increasing irrigation for crop production would surge energy demand for water
conveyance, deeper pumping, and desalination, so FEW system models account for
the energy cost of different irrigation scenarios. Additionally, bioenergy expansion
may have significant impacts on the water cycle, depending on the regional climate
and hydrologic conditions.
Fertilizing and harvesting biomass on marginal land may substantially increase
sediment and nutrient discharge, exacerbating already stressed inland and coastal
waters. Furthermore, the relative water consumption of perennial versus annual
crops differs strongly depending both on crop type and location.
Therefore, FEW system models must simulate various potential biomass crops’
effects on local water cycles, accounting for regional climate and other impacts, to
answer key questions such as: Where and which bioenergy crops can be produced
sustainably (both economically and environmentally) without stressing water supply, soil quality, or food production, and how will they affect regional climate and
carbon footprint?
15.3.3 Water–Food
Water scarcity, variability, and uncertainty are already threatening US agriculture
resilience, with increasing vulnerability to drought. Agricultural productivity
depends on optimal temperature and reliable water supply, and agronomic advances
have not reduced crop yield sensitivity to drought (Hatfield et al. 2014).
As food demand continues to increase, rainfall alone will not support the needed
yield increases, and greater strain will be placed on water resources. Shifts in crop
F. R. Miralles-Wilhelm
Such changing agricultural practices could have far-reaching impacts for water
quantity and quality, cascading into long-term effects on crop yield and food security. Consequently, modeling of FEW systems should represent changing bioenergy
land use and its impact on crop distribution and yield.
Growing bioenergy on marginal land in the form of perennial vegetation may
alleviate food-versus-fuel trade-off concerns while reducing the carbon debt and
indirect land-use costs associated with food-based biofuels. However, such expansion could have regional and widespread effects on climate, land, and water, which
must be assessed using an advanced coupled model system.
Thus, FEW system models should address key questions such as: Will largescale deployment of the new generation of heat-resistant, drought-tolerant, or
higher-reflectivity crop hybrids deliver high yields, increase water use efficiency, or
reduce canopy temperatures sufficiently to meet future food demand under available
water supply while maintaining soil and water quality and offsetting greenhouse gas
warming? If not, what will the deficiencies be?
15.3.2 Energy–Water
Increasing irrigation for crop production would surge energy demand for water
conveyance, deeper pumping, and desalination, so FEW system models account for
the energy cost of different irrigation scenarios. Additionally, bioenergy expansion
may have significant impacts on the water cycle, depending on the regional climate
and hydrologic conditions.
Fertilizing and harvesting biomass on marginal land may substantially increase
sediment and nutrient discharge, exacerbating already stressed inland and coastal
waters. Furthermore, the relative water consumption of perennial versus annual
crops differs strongly depending both on crop type and location.
Therefore, FEW system models must simulate various potential biomass crops’
effects on local water cycles, accounting for regional climate and other impacts, to
answer key questions such as: Where and which bioenergy crops can be produced
sustainably (both economically and environmentally) without stressing water supply, soil quality, or food production, and how will they affect regional climate and
carbon footprint?
15.3.3 Water–Food
Water scarcity, variability, and uncertainty are already threatening US agriculture
resilience, with increasing vulnerability to drought. Agricultural productivity
depends on optimal temperature and reliable water supply, and agronomic advances
have not reduced crop yield sensitivity to drought (Hatfield et al. 2014).
As food demand continues to increase, rainfall alone will not support the needed
yield increases, and greater strain will be placed on water resources. Shifts in crop
F. R. Miralles-Wilhelm