Abstract Optimizing nitrogen (N) application rate is essential for effective N management and requires an understanding of crop growth dynamics, nutrient partitioning, cultivar traits, and soil characteristics. The effects of seven in‐season N rates (37–391 kg N ha −1 ) on dry matter (DM) and N accumulation and partitioning at early‐ and late‐growth stages and tuber yield and quality of potato ( Solanum tuberosum L.) cv. Goldrush grown in the sandy soils of central Wisconsin were evaluated over three growing seasons. The objective was to identify optimal regression models to achieve a sustainable balance between maximizing marketable tuber yield and economic profitability. In‐season N applications improved total N uptake and tuber N concentration but reduced DM and N partitioning to tuber. Yield gains were most consistent between 277 and 295 kg N ha − 1 , with no additional benefit beyond this range. While the quadratic and linear‐plateau models best described total and marketable yield, respectively, model fits were similar, and critical N rates varied by <7%. Relative yield normalization improved model accuracy across years. These findings support model‐based, site‐ and cultivar‐specific N recommendations to improve N use efficiency and the need for broader, multi‐environment datasets to refine predictive models and ensure both agronomic performance and environmental sustainability in potato production systems.
Correia et al. (Fri,) studied this question.