Plant and Soil

, Volume 339, Issue 1–2, pp 69–81

Switchgrass for forage and bioenergy: harvest and nitrogen rate effects on biomass yields and nutrient composition

  • John A. Guretzky
  • Jon T. Biermacher
  • Billy J. Cook
  • Maru K. Kering
  • Jagadeesh Mosali
Regular Article

DOI: 10.1007/s11104-010-0376-4

Cite this article as:
Guretzky, J.A., Biermacher, J.T., Cook, B.J. et al. Plant Soil (2011) 339: 69. doi:10.1007/s11104-010-0376-4

Abstract

Switchgrass (Panicum virgatum L.) may have value as forage and a bioenergy feedstock. Our objective was to evaluate how harvest system and N fertilizer rates affected biomass yield and nutrient composition of young stands of switchgrass (cv. Alamo) in the southern Great Plains, USA. Nitrogen fertilization increased biomass yields from 10.4, 10.8, and 12.2 Mg ha−1 at 0 kg N ha−1 to 13.7, 14.6, and 21.0 Mg ha−1 at 225 kg N ha−1 when harvested after seed set (October), after frost (December), and twice per year after boot stage (July) and frost, respectively. Nutrient concentrations and removal were generally twice as great when biomass was harvested twice versus once per year. Precipitation strongly affected biomass yields across the two years of these experiments. When late-summer precipitation is available to support regrowth in this environment, harvesting switchgrass twice per year will result in greater biomass yields. Harvesting twice per year, however, will increase fertilization requirements and reduce feedstock biomass quality. Switchgrass harvested during mid-summer after boot stage was of poor forage quality. To have value as a dual-purpose forage and bioenergy feedstock, switchgrass would need to be utilized during spring to early summer while in a vegetative stage.

Keywords

Biofuels Biomass quality Cellulosic feedstock production Ethanol Forage quality 

Abbreviations

ADF

Acid detergent fiber

CRP

Conservation Reserve Program

IVDMD

In vitro dry matter digestibility

NIRS

Near infrared reflectance spectroscopy

NDF

Neutral detergent fiber

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • John A. Guretzky
    • 1
  • Jon T. Biermacher
    • 2
  • Billy J. Cook
    • 2
  • Maru K. Kering
    • 2
  • Jagadeesh Mosali
    • 2
  1. 1.Department of Agronomy and HorticultureUniversity of Nebraska-LincolnLincolnUSA
  2. 2.Agricultural DivisionThe Samuel Roberts Noble FoundationArdmoreUSA

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