Reduced Nitrogen Losses after Conversion of Row Crop Agriculture to Perennial Biofuel Crops
- Candice M. Smitha,
- Mark B. David *ab,
- Corey A. Mitchellab,
- Michael D. Mastersa,
- Kristina J. Anderson-Teixeiraa,
- Carl J. Bernacchiace and
- Evan H. DeLuciaacd
- a Energy Biosciences Institute, Univ. of Illinois at Urbana-Champaign, Urbana, IL
b Dep. of Natural Resources and Environmental Sciences, Univ. of Illinois at Urbana-Champaign, Urbana, IL
c DeLucia, Dep. of Plant Biology, Univ. of Illinois at Urbana-Champaign, Urbana, IL
e USDA–ARS, Global Change and Photosynthesis Research Unit, Urbana, IL
d Institute of Genomic Biology, Univ. of Illinois at Urbana-Champaign, Urbana, IL
Current biofuel feedstock crops such as corn lead to large environmental losses of N through nitrate leaching and N2O emissions; second-generation cellulosic crops have the potential to reduce these N losses. We measured N losses and cycling in establishing miscanthus (Miscanthus × giganteus), switchgrass (Panicum virgatum L. fertilized with 56 kg N ha−1 yr−1), and mixed prairie, along with a corn (Zea mays L.)–corn–soybean [Glycine max (L.) Merr.] rotation (corn fertilized at 168–202 kg N ha−1). Nitrous oxide emissions, soil N mineralization, mid-profile nitrate leaching, and tile flow and nitrate concentrations were measured. Perennial crops quickly reduced nitrate leaching at a 50-cm soil depth as well as concentrations and loads from the tile systems (year 1 tile nitrate concentrations of 10–15 mg N L−1 declined significantly by year 4 in all perennial crops to <0.6 mg N L−1, with losses of <0.8 kg N ha−1 yr−1). Nitrous oxide emissions were 2.2 to 7.7 kg N ha−1 yr−1 in the corn–corn–soybean rotation but were <1.0 kg N ha−1 yr−1 by year 4 in the perennial crops. Overall N balances (atmospheric deposition + fertilization + soybean N2 fixation – harvest, leaching losses, and N2O emissions) were positive for corn and soybean (22 kg N ha−1 yr−1) as well as switchgrass (9.7 kg N ha−1 yr−1) but were −18 and −29 kg N ha−1 yr−1 for prairie and miscanthus, respectively. Our results demonstrate rapid tightening of the N cycle as perennial biofuel crops established on a rich Mollisol soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2013. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.