Split-nitrogen application with cover cropping reduces subsurface nitrate losses while maintaining corn yields

Giovani Preza-Fontes, Cameron M. Pittelkow, Kristin D. Greer, Rabin Bhattarai, Laura E. Christianson

Research output: Contribution to journalArticlepeer-review


Artificial subsurface drainage is essential to sustain crop production in many areas but may also impair water quality by exacerbating nitrate (NO3)–nitrogen (N) delivery downstream. Cover crops and split-N application have been promoted as key conservation practices for reducing NO3–N losses, but few studies have simultaneously assessed their effect on water quality and crop productivity. A field study was conducted to evaluate the effects of N application timing and cover crops on subsurface drainage NO3–N losses and grain yield in continuous corn (Zea mays L.). Treatments were preplant-N: 224 kg N ha–1 split-applied with 60% fall + 40% preplant in 2018, or as single preplant applications in 2019 and 2020; split-N: 40% preplant + 60% side-dress (V6–V7); split-N + cover crop (CC): Split-N + cereal rye (Secale cereale L.); and a zero N plot as the control. Across the 3-yr study period, split-N + CC significantly reduced flow-weighted NO3–N concentration and NO3–N loss by 35 and 37%, respectively, compared with preplant-N. However, flow-weighted NO3–N concentration (4.3 mg L–1) and NO3–N loss (22.4 kg ha–1) with split-N were not significantly different from either preplant-N (4.8 mg L–1 and 26.4 kg ha–1, respectively) or split-N + CC (3.1 mg L–1 and 16.7 kg ha–1, respectively). Corn yield was significantly lower in the control treatment but did not differ among N fertilized treatments in any year. These results indicate that combining split-N application with cover crops holds promise for meeting the statewide interim milestone NO3–N reduction target of 15% by 2025 without negatively impacting crop productivity.

Original languageEnglish (US)
JournalJournal of Environmental Quality
StateAccepted/In press - 2021

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law


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