Biomass Production in Switchgrass across the United States: Database Description and Determinants of Yield

Abstract

Fundamental to deriving a sustainable supply of cellulosic feedstock for an emerging biofuels industry is understanding how biomass yield varies as a function of crop management, climate, and soils. Here we focus on the perennial switchgrass (Panicum virgatum L.) and compile a database that contains 1190 observations of yield from 39 fi eld trials conducted across the United States. Data include site location, stand age, plot size, cultivar, crop management, biomass yield, temperature, precipitation, and information on land quality. Statistical analysis revealed the major sources of variation in yield. Frequency distributions of yield for upland and lowland ecotypes were unimodal, with mean (±SD) biomass yields of 8.7 ± 4.2 and 12.9 ± 5.9 Mg ha -1 for the two ecotypes, respectively. We looked for, but did not fi nd, bias toward higher yields associated with small plots or preferential establishment of stands on high quality lands. A parametric yield model was fi t to the data and accounted for one-third of the total observed variation in biomass yields, with an equal contribution of growing season precipitation, annual temperature, N fertilization, and ecotype. Th e model was used to predict yield across the continental United States. Mapped output was consistent with the natural range of switchgrass and, as expected, yields were shown to be limited by precipitation west of the Great Plains. Future studies should extend the geographic distribution of fi eld trials and thus improve our understanding of biomass production as a function of soil, climate, and crop management for promising biofuels such as switchgrass.

Dedicated Energy Crops and Crop Residues for Bioenergy Feedstocks in the Central and Eastern USA

“…A database of switchgrass studies from 39 field sites in 17 states supports a single harvest for bioenergy [56]. Harvesting after frost allows N and other nutrients to be mobilized into roots for storage during winter and use for new growth the following spring [50].…”

Switchgrass Biofuel Production on Reclaimed Surface Mines: I. Soil Quality and Dry Matter Yield

“…Cultivars are classified into lowland and upland phenotypic groups, with both groups growing well throughout the switchgrass adaptation zone [33]. Lowland ecotypes tend to be more productive [5,31], but this advantage decreases with increasing latitude [4]. The ability to grow with low or little fertilizer inputs and less pesticide application provides economic and environmental advantages over annual crops that require annual seeding and fertilization [30], and that may provide less winter cover for soil and water conservation.…”

Switchgrass Response to Nitrogen Fertilizer Across Diverse Environments in the USA: a Regional Feedstock Partnership Report

“…However, Mulkey et al [23] reported no benefit with N application rates above 56 kg ha −1 on switchgrass-dominated Conservation Reserve Program (CRP) lands in South Dakota. In an analysis of 19 switchgrass research publications in the literature, Wullschleger et al [34] noted that both upland and lowland switchgrass ecotypes responded to total N levels of approximately 100 kg N ha −1 ; however, in some cases, the 0 N control produced as much biomass as switchgrass treated with 100 kg N ha −1 . A major question regarding switchgrass management as a bioenergy crop is optimizing N application rate at the field scale since excessive N fertilization may result in adverse environmental and economic effects.…”