Opportunities to improve nitrogen use efficiency in an intensive vegetable system without compromising yield

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Intensive vegetable cropping relies on substantial nitrogen (N) inputs, leading to significant environmental losses, including nitrous oxide (N2O) emissions.
• Optimizing N management is crucial for reducing environmental impact while maintaining crop productivity.

Purpose of the Study:

• To investigate methods for reducing N input in intensive vegetable systems without compromising yield.
• To assess the impact of reduced N input and nitrification inhibitors on N losses and N2O emissions.

Main Methods:

• Field trial comparing control (no N), manure only, grower practice (GP), and 2/3 GP treatments.
• Evaluated treatments with and without 3,4-dimethylpyrazole phosphate (DMPP), a nitrification inhibitor.
• Utilized 15N-labeled fertilizer to track N recovery in the GP treatment.

Main Results:

• Reducing N input by one-third did not affect celery yield or apparent N use efficiency (ANUE).
• Manure-only application reduced yield compared to GP.
• DMPP increased ANUE but did not improve yield.
• GP treatment resulted in over 50% N loss and significant N2O emissions (10 kg N ha-1).
• Reduced N input or manure-only application decreased N2O emissions by over 70% relative to GP.

Conclusions:

• There is a clear opportunity to reduce N input and N2O emissions in intensive vegetable systems.
• Sustainable reductions in N fertilizer are achievable without compromising vegetable yield.
• Nitrification inhibitors can enhance N use efficiency.