ADAS Study Finds Limited Benefits from Variable Rate Nitrogen Applications

New research from ADAS has found that variable rate nitrogen applications in winter wheat, winter barley, and oilseed rape fields may not be as beneficial as previously thought.

The study, which spanned five years across 11 commercial farms in the UK, discovered that variable rate nitrogen (VRN) applications would increase yields by only about 0.05 t/ha and improve profits by roughly £10/ha compared to a flat optimum nitrogen rate.

While VRN did result in small reductions in greenhouse gas emissions per tonne of crop produced, the environmental benefits were modest at best.

ADAS project lead Dr Kate Storer noted that 'crop needs are not uniform, even within the same field', highlighting the importance of precision farming tools for optimizing nitrogen applications.

The study's findings indicate that tailoring nitrogen applications by variably applying nitrogen within a field offers relatively little gain over applying an accurate flat optimum nitrogen rate across the field.