Biomass, nitrogen, and carbon loss from the novel oilseed pennycress relative to annual ryegrass and cereal rye

Abstract

The rate of pennycress residue decomposition and mineralization is critical in determining potential nutrient availability for following crops. To better understand pennycress decomposition, we examined biomass, nitrogen, and carbon loss from wild pennycress, gene edited AOP2 knockout pennycress, annual ryegrass, and cereal rye. Biomass was collected from all crops at the time of cash crop planting, and 20 g of biomass was placed in individual mesh forage bags (50 ± 10 mm). We placed 99 bags from each crop between rows of corn (n = 5) on the soil surface of the dominant soil types (SA and DR) at the ISU farm. Replicate bags were collected from each soil type over the following 84 days, weighed for biomass, and analyzed for carbon and nitrogen in the plant residue. Loss of biomass differed by crop and soil type (F = 3.7_3,32, p = 0.023) with annual ryegrass losing biomass most rapidly followed by cereal rye, wild-type pennycress, and the domesticated low glucosinolate, AOP2 knockout, pennycress. Nitrogen (F = 8.5_3,36, p < 0.0001) and carbon (F = 67.5_3,36, p < 0.0001) losses differed by crop and not soil type following a similar trend as biomass loss. Our results suggest that both wild-type and AOP2 knockout pennycress can be expected to decompose similarly to a rye cover crop but with slower nutrient loss. Pennycress has potential to act as an effective short-term nutrient sink in agroecosystems.

Keywords:

• Cover crop decomposition
• pennycress
• winter cover crop
• winter cash crop

Abbreviations

DR	=	Drummer and Elpaso soils
ISU	=	Illinois State University
K	=	decomposition rate
SA	=	Saybrook soils

Acknowledgments

C.M. O’Reilly and J.C. Sedbrook provided comments on early versions of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Data supporting the findings of this study are available upon request from the corresponding author, R.M.

Additional information

Funding

This work was supported by the U.S. Department of Agriculture; Grant: Agriculture and Food Research Initiative Competitive Grant No. 2019-69012-29851

Notes on contributors

Ryan T. Meyer

Ryan Meyer is a Master’s Student in the School of Biological Sciences at Illinois State University. He has previously studied environmental science and his current work focuses on the potential for cover crops to improve water quality in the Midwestern United States and in downstream aquatic ecosystems.

Nicholas J. Heller

Dr. Nicholas Heller is an Assistant Professor of Crop Sciences in the Department of Agriculture at Illinois State University. He is actively involved in assessing and analyzing regenerative ag practices with a specific focus on cover crop species and their interactions with preceding and following crops. Dr. Heller teaches breeding, genetics, agronomy, and statistics courses.

Alex W. Hafner

Alex Hafner is a recent graduate of Illinois State University achieving a B.S. in biology with a focus on plant genetics. Hafner currently works as a research assistant in a biometical genetics laboratory.

William L. Perry

Bill Perry is an aquatic ecologist studying the role of watershed management practices on stream water quality in the midwest. Perry has studied the role of eutrophication on lakes in northern Alaska, invasive species in the midwest and now controls of water quality in central Illinois. A major focus of the laboratory is on the potential for existing and new cover crops in helping improve biodiversity and water quality in central IL streams and downstream systems.