Location: Natural Resource Management ResearchTitle: Growing perennial forages for biomass Author
Submitted to: Extension Publications
Publication Type: Experiment Station
Publication Acceptance Date: 8/24/2012
Publication Date: 8/1/2013
Citation: Sanderson, M.A., Cannayen, I. 2013. Growing perennial forages for biomass. Extension Publications. Chapter 4. Pages 17-21. IN: S. Bittman and D. Hunt (editors). Cool Forages-Advanced management of temperate forages. Pacific Field Corn Association, Agassiz, British Columbia, Canada. Interpretive Summary: Perennial forage crops, especially some of the high-yielding tall-growing grasses, offer distinct advantages for bioenergy production including long-term persistence, relatively low input requirements, potential to store carbon in the soil, and a positive energy balance. Several forages have been studied for biomass feedstock production including switchgrass, Miscanthus, reed canarygrass, and alfalfa. This production guide summarizes key management practices for perennial crops grown for biomass to achieve: (i) rapid establishment to generate harvestable biomass in the seeding year, (ii) highly efficient use of soil and fertilizer N to minimize external energy inputs, and (iii) timely harvest to maximize yields of cellulosic biomass. Growing perennial forages for sustainable bioenergy production offers an exciting future alternative for farmers. Current fossil fuel prices, however, limit the competitiveness of renewable energy from biomass, absent significant government subsidies. Valuing additional ecosystem services provided by perennial crops, such as soil carbon sequestration, reduced erosion, and offset greenhouse gas emissions, could alter the competitive balance.
Technical Abstract: Recent attention given to converting biomass into ethanol to fuel cars and trucks or burning it to generate electricity has captured society’s interest. There are three main routes for converting biomass into usable forms of energy or other chemical end products: (i) biochemical, (ii) thermochemical and (iii) direct thermal conversion or the simple combustion of biomass. Among biofuels, the major emphasis at present is on transportation fuels for either blending (e.g. ethanol – mixed with gasoline) or drop in (e.g. biodiesel, jet fuel – directly used) fuel types. Perennial forages, especially some of the high-yielding tall-growing grasses, offer many advantages as bioenergy crops including long-term persistence, relatively low input requirements, potential to store carbon in the soil, and a positive energy balance. Two highly promising grasses for biomass feedstock production are switchgrass and Miscanthus. Switchgrass is productive in many environments including marginal lands. Miscanthus, a tall growing warm-season grass native to Asia, has not been researched extensively as a bioenergy crop in North America and more information is needed on its range of adaptation, yield, and persistence in different environments. Farmers are familiar with managing perennial forage crops, thus shifting to bioenergy cropping should not be a difficult transition. Management of perennial forages for bioenergy must focus on (i) rapid establishment to generate harvestable biomass in the seeding year, (ii) highly efficient management of soil and fertilizer N to minimize external energy inputs, and (iii) harvest management to maximize yields of cellulosic biomass.