Chapter 3. Bioenergy Crops: Delivering More Than Energy

Abstract

As population growth and climate change put additional pressure on an already strained agricultural and land management system, bioenergy and biomaterial technology is being developed with the promise of better greenhouse gas balances and amidst concerns about increased land use change and impacts on water resources and other externalities associated with agricultural processes. Yet, much of the impacts of bioenergy and biomaterial cropping depend on how this large scale deployment will occur. Proactively designing production systems that purposefully incorporate the achievement of sustainability objectives or ecosystem services along with the biomass feedstock is possible and can be achieved by exploiting specific traits of second generation perennial lignocellulosic bioenergy crops. Compared to annual row crops, perennials such as switchgrass, Miscanthus, other perennial grasses, and short rotation woody crops share a deeper root system, a general better ability to thrive on poorer soils, a lower dependence on fertilizer inputs, and at least for some, management options that can be friendly to wildlife. A deeper root system carries many potentially strategic benefits such as the ability to survive more extreme conditions of drought and flooding after establishment, as well as the potential for carbon sequestration deeper in the soil profile. Potential drawbacks, such as the possibility of a larger water consumption by perennial crops, also need to be factored in the decisions and planning. By selecting specific positions on the landscape to grow perennial bioenergy crops and enable these ecosystem services, we can design bioenergy landscapes that balance productivity and environmental performance, are socially acceptable and deliver on much more than bioenergy and bioproducts.