Establishing the relationship of soil nitrogen immobilization to cereal rye residues in a mulched system

Alwyn Williams, M. Scott Wells, David A. Dickey, Shuijin Hu, Jude Maul, Daniel T. Raskin, S. Chris Reberg-Horton, Steven B. Mirsky

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Background and aims: Soil nitrogen (N) immobilization from cover crop residues may help suppress weeds. We established a gradient of cereal rye shoot biomass to determine the extent that soil N can be immobilized and its effect on redroot pigweed (Amaranthus retroflexus L.). Methods: A microplot study was conducted in no-till cereal rye (Secale cereale L.)—soybean (Glycine max L. (Merr.)) systems at two sites in eastern USA. Microplots received 0, 2000, 5000, 8000, 12,000 or 15,000 kg ha−1 of cereal rye shoot biomass, and were injected with two mg 15N kg−1 soil 5 cm below the soil surface. Pigweeds were sown and allowed to germinate. Results: Maximum rates of cereal rye shoot decomposition were observed at ≥5000 kg ha−1. Although cereal rye shoot N declined, shoots became enriched with 15N, indicating fungal transfer of soil N to shoots. Soil inorganic N declined by an average of 5 kg N ha−1. Pigweed tissue N and biomass were reduced in the presence of cereal rye. The magnitude of pigweed N reduction was similar across all shoot application rates. Conclusions: We found weak evidence for a cereal rye shoot-based N immobilization mechanism of weed suppression. Our results indicate N immobilization may be primarily due to root residues.

Original languageEnglish (US)
Pages (from-to)95-107
Number of pages13
JournalPlant and Soil
Issue number1-2
StatePublished - May 1 2018

Bibliographical note

Publisher Copyright:
© 2018, The Author(s).

Copyright 2018 Elsevier B.V., All rights reserved.


  • Cover crop mulch
  • N immobilization
  • N stable isotope
  • Residue decomposition
  • Secale cereale L
  • Weed suppression

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