Effects of Novel Nitrogen Smart Fertilizer Formulations on Potato Production and Quality

Purpose Nitrogen (N) fertilization poses a series of concerns related to its impact on agroecosystems. This study evaluated a possible strategy to overcome those problems, investigating innovative urea smart fertilizers containing nitrification inhibitors (Methylene Blue – BM), urease inhibitor (Gallic Acid – GA), and their combinations (BMGA and GABM) for potato (Solanum tuberosum L.) fertilization. Methods A two–year study (2023–2024) was conducted on potato crop to compare the effects of four innovative urea smart fertilizers (GA, BM, GABM, BMGA) and a commercially available urea smart fertilizer (NBPT) applied at 100% and 75% of the recommended N dose (RND) on plant phenology, crop yield, crop biometry, tuber N content, nitrate (NO₃⁻) leaching, and soil N contents. The unfertilized and business as usual fertilization, with urea provided at 100% of RND, were used as controls. Results A model based on cumulated growing degree days (GDD) and Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie (BBCH) stage revealed that the smart fertilizers did not affect potato plant phenology. Soil analyses did not yield insightful results. Under BM–100, total and marketable yields, and plant height were the highest (40.3 ± 4.1 and 34.3 ± 3.8 t ha− 1, 56.3 ± 8.2 cm). Notably, smart urea at 75% dosage achieved yields comparable to commercial urea at 100% (on average 25.4 ± 2.8 t ha− 1 of marketable yield) and produced tubers with 7% less Total Kjeldhal nitrogen (TKN) content. Conversely, the highest NO3– concentration in leaching was found under NBPT–100 (169.2 ± 18.2 mg L–1) and BMGA–100 (198.7 ± 21.1 mg L–1). Conclusion This pioneering study identifies BM as a promising nitrification inhibitor for enhancing potato yield, underscoring the utility of smart urea in reducing agricultural N inputs while maintaining productivity.