Influence of soil inorganic nitrogen and root diameter size on legume cover crop root decomposition and nitrogen release

Arun D. Jani, Julie M. Grossman, Thomas J. Smyth, Shuijin Hu

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Aims: Legume cover crops are primarily grown for their contribution to soil N pools, but the effect that this added N has on cover crop root decomposition and N release is poorly understood. Our primary objective was to determine the effect that soil N and root diameter size have on root decomposition and N release. Methods: We determined coarse (>1-mm diameter) and fine (<1-mm diameter) root distribution for crimson clover (Trifolium incarnatum) and hairy vetch (Vicia villosa Roth) using greenhouse-grown plants, and followed with a 12-week incubation in which coarse and fine roots from both species were incubated under natural and elevated (200 kg ha−1) soil N levels. Results: Crimson clover and hairy vetch consisted primarily of fine roots (≥79 %), which decomposed and released N faster than coarse roots. Soil N addition had a small positive effect on root decomposition, but an inconsistent effect on root N release. There was a net increase in soil inorganic N for all treatments after 12 weeks. Conclusion: These results improved our understanding of decomposition and N release from crimson clover and hairy vetch roots, and are valuable to farmers seeking to better manage soil C and N pools.

Original languageEnglish (US)
Pages (from-to)57-68
Number of pages12
JournalPlant and Soil
Volume393
Issue number1-2
DOIs
StatePublished - Aug 29 2015

Keywords

  • Fine and coarse roots
  • Legume cover crops
  • Nitrogen release
  • Root decomposition

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