Modeling spatial and dynamic variation in growth, yield, and yield stability of the bioenergy cropsMiscanthus × giganteusandPanicum virgatumacross the conterminousUnitedStates

Abstract

AbstractC4perennial grasses are being considered as environmentally and economically sustainable high yielding bioenergy feedstocks. Temporal and spatial variation in yield across the conterminiousUnitedStates is uncertain due to the limited number of field trials. Here, we use a semi‐mechanistic dynamic crop growth and production model to explore the potential ofMiscanthus × giganteus(Greef et.Deu.) andPanicum virgatumL. across the conterminousUnitedStates. By running the model for 32 years (1979–2010), we were able to estimate dry biomass production and stability. The maximum rainfed simulated end‐of‐growth‐season harvestable biomass forM. × giganteuswas ca. 40 Mg ha−1and ca. 20 Mg ha−1forP. virgatum. In addition, regions of the southeasternUnitedStates were identified as promising due to their high potential production and stability and their relative advantage when compared with county‐level maize biomass production. Regional and temporal variation was most strongly influenced by precipitation and soil water holding capacity.Miscanthus × giganteuswas on average 2.2 times more productive thanP. virgatumfor locations where yields were ≥10 Mg ha−1. The predictive ability of the model forP. virgatumwas tested with 30 previously published studies covering the eastern half of theUnitedStates and resulted in an index of agreement of 0.71 and a mean bias of only −0.62 Mg ha−1showing that, on average, the model tended to only slightly overestimate productivity. This study provides with potential production and variability which can be used for regional assessment of the suitability of dedicated bioenergy crops.