Legume cover crops and tillage impact nitrogen dynamics in organic corn production

Alexander M. Liebman, Julie Grossman, Matthew Brown, M. Scott Wells, S. C. Reberg-Horton, Wei Shi

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Cover cropping and reduced tillage are two management practices that increase ecosystem services in agroecosystems. However, their interactive effects on N dynamics and cash crop yield are under-explored. In this study, four different termination approaches, employing no-till and tillage, and organic and conventional techniques were used with four winter annual leguminous cover crop species to investigate the combined effect on plant-available nitrogen (PAN) and subsequent organic corn (Zea mays L.) yield. Termination treatments included roller-crimping, flail-mowing, disking, and herbicide application with cover crops of Austrian winter pea (Pisum sativum L. subs. arvense, AWP), hairy vetch (Vicia villosa var. AU Early Cover, HV), balansa clover [Trifolium michelianum Savi ssp. balansae (Boiss.) Ponert, BC] and crimson clover (Trifolium incarnatum var. Dixie, CC). Plant-available N (NO -3 and NH+4) was determined using biweekly soil inorganic N extractions and resin probes. Cover crop biomass, cover crop C/N ratio, and cover crop total N were measured prior to termination. Nitrogen was most available from AWP and HV across termination methods at 6 to 10 wk after termination. Disked HV contributed highest levels of N across all 16 cropping by termination combinations. Highest biomass N was found in HV (226 kg ha-1), followed by AWP (189 kg ha-1) and CC (181 kg ha-1). Corn yield ranged widely, from 0.23 Mg ha-1 in 0 N control to >9 Mg ha-1 in HV and AWP treatments. Cover crop species plays an important role in N dynamics, frequently influencing soil processes to a more significant degree than termination approach.

Original languageEnglish (US)
Pages (from-to)1046-1057
Number of pages12
JournalAgronomy Journal
Issue number3
StatePublished - May 1 2018

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© 2018 by the American Society of Agronomy.


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