Cover Crops and Soil Amendments: New Insights on Nitrogen Distribution

Strategic Insights -

Researchers at Louisiana State University have published a new study on the impact of cover crops and soil amendments on nitrogen distribution in soil aggregates under no-till management. The study, funded by the USDA-ARS National Program 216 and the Mississippi Soybean Promotion Board, examined the effects of cover crops and fertilization treatments on nitrogen distribution in topsoil. The results showed that microaggregates dominated and contained the largest nitrogen stock, and that soil amendments, particularly poultry litter with flue gas desulfurization gypsum and lignite, stabilized aggregates and increased nitrogen accumulation.

Key Takeaways:

  • The study examined the effects of cover crops and fertilization treatments on nitrogen distribution in topsoil under no-till management, a system commonly used in corn production.
  • Microaggregates (0.25-0.053 mm) dominated (38.3-50.1%) and contained the largest nitrogen stock (mean: 1.09 Mg ha-1) in a no-till rainfed corn system.
  • Cover crops had no significant effect on nitrogen content and stock, but poultry litter with flue gas desulfurization gypsum and lignite improved nitrogen content and stock in 1-0.5 mm aggregates.
  • Long-term studies are needed to assess the benefits of cover crops and soil amendments on soil health.
  • The study supports the importance of soil amendments, particularly poultry litter with flue gas desulfurization gypsum and lignite, in stabilizing aggregates and increasing nitrogen accumulation.
  • The research was funded by the USDA-ARS National Program 216 and the Mississippi Soybean Promotion Board.

Statistics:

  • 38.3-50.1% of microaggregates dominated in the no-till rainfed corn system.
  • 1.09 Mg ha-1 was the mean nitrogen stock in microaggregates.
  • 25.2-41.9% of bulk soil nitrogen was contributed by microaggregates.
  • 1-0.5 mm aggregates showed improved nitrogen content and stock with poultry litter treatment.
  • 2 mm aggregates showed enhanced bulk soil nitrogen and stock with poultry litter with flue gas desulfurization gypsum and lignite treatment.

Sources:

  • Impact of winter cover crop and soil amendments on total and aggregate-associated nitrogen in a no-till corn field. npj Sustainable Agriculture, 2025,3(1):1-10.
  • USDA-ARS National Program 216
  • Mississippi Soybean Promotion Board
  • Louisiana State University Agricultural Center (contact: Wei Dai)
  • doi.org.sdpl.idm.oclc.org/10.1038/s44264-025-00077-x
  • NewsRx LLC.