Strategic Nitrogen Recommendations for Potatoes: Soil- and Climate-Specific Insights from the Model-Based Identifying NEMO Framework

Sustainable potato production requires optimized nitrogen (N) management to balance productivity and environmental protection. Determining crop N requirements before planting remains challenging due to large variations in weather, soil properties, and yield potential across years and regions. We apply a model-based framework, Identifying Nitrogen Ecophysiologically Modeled Optimum (NEMO), using the STICS crop model and decades of climate data (1984–2022) to simulate yield-to-N responses across four agroclimatic regions in Prince Edward Island (PEI), Canada. Results indicate that soils with lower sand content (e.g., CTW and ARY) sustain higher productivity and require less N (116–152 kg ha−1) than the sandier CLO soil (166–231 kg ha−1) to achieve a fresh yield of 40 t ha−1 at 80% moisture, with recommended N rates generally lower in Western PEI (Summerside, 121–175 kg ha−1) than in Eastern PEI (Souris, 149–231 kg ha−1) across the major soils. Recommended rates are 27–55 kg ha−1 below guidelines. Targeting medium yields supports a two-stage management strategy that minimizes excess N risk and improves resilience under variable seasonal conditions. A moderate N reduction of about 35 kg ha−1 from current recommendations results in an average fresh yield loss of 2.6 t ha−1 (CAD $511 ha−1), partially offset by fertilizer savings (CAD $19 ha−1) and substantial environmental benefits valued at CAD $385–2870 ha−1. These findings highlight that moderate, risk-based N management can deliver both economic and ecological gains for sustainable potato production.