BioEnergy Research

, Volume 1, Issue 2, pp 153–162

Nitrogen-Use Dynamics in Switchgrass Grown for Biomass

Article

DOI: 10.1007/s12155-008-9014-x

Cite this article as:
Lemus, R., Parrish, D.J. & Abaye, O. Bioenerg. Res. (2008) 1: 153. doi:10.1007/s12155-008-9014-x

Abstract

This work examines N use by switchgrass (Panicum virgatum L.). A study was conducted on two well-established ‘Cave-in-Rock’ switchgrass stands in Blacksburg (37° 11′ N, 80° 25′ W) and Orange (38° 13′ N, 78° 07′ W) Virginia, USA. Plots were fertilized in 2001 (year 1) with 0, 90, 180, or 270 kg N per hectare. No additional N was applied in 2002 (year 2) and 2003 (year 3), and biomass was harvested in July and November for years 2 and 3 (but only in November of year 1). Root and soil samples were collected in May, July, September, and November each year and analyzed for N. Nitrogen fertilization did not increase yields in 2001 (year 1), but it did provide residual benefits in 2002 (year 2) and 2003 (year 3). Root-N levels at 15 cm depth increased with fertilization, fluctuated seasonally between roots and shoots, and root-N was reduced over the course of the study. With two harvests per year, about 100 kg N hectare per year were removed in biomass, even in plots with no N added—suggesting N already present in the soils (at 15 cm depth) contributed to yields; but the soil mineral-N pools were reduced by the end of year 3. Nitrogen-use efficiency, apparent N recovery, and partial factor productivity were reduced with higher N applications. The data support the notion that biomass production can be achieved with minimal N inputs, but stands must be managed to maintain that N reserve over the long term. There is also a need to quantify the N pool to depths greater than 15 cm in other agro-ecoregions.

Keywords

Bioenergy crops Biofuel Fertilization Mineralization Nitrogen removal 

Abbreviations

ANR

apparent nitrogen recovery

KCl

potassium chloride

LSD

least significant difference

NUE

nitrogen use efficiency

PFP

partial factor productivity

SMN

soil mineral nitrogen

Copyright information

© Springer Science+Business Media, LLC. 2008

Authors and Affiliations

  1. 1.Department of Plant and Soil SciencesMississippi State UniversityStarkvilleUSA
  2. 2.Department of Crop and Soil Environmental SciencesVirginia TechBlacksburgUSA

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