LAUSR

ABSTRACT Nitrogen (N), phosphorus (P) and potassium (K) management are critical in optimizing potato yield, which is also influenced by environmental factors, and crop response to these factors may vary with cultivars. Application doses and times of NPK fertilizers and use of tolerant genotypes are the most commonly employed strategies for the amelioration of potato yield. The objective of this work was to assess the response of two potato cultivars distinct by their earliness characters concerning tuber maturation (mid-early and mid-late), to different NPK regimes. Experiments were carried out with Spunta and Daifla cultivars. The impact of deficiency, optimum and excess NPK rates was tested for different tuberization stages. This study has emphasized the importance of the cultivar in potato plants response to NPK fertilization doses. Spunta showed a higher production performance compared to Daifla. Daifla was distinguished by a good vegetation throughout the development cycle but gave a very low tuber yield. Abbreviation: NPK: Nitrogen (N), phosphorus (P) and potassium (K), DAP: Day after planting, I2KI: Potassium Iodide, HCl: Hydrochloric acid, P2O5: Phosphorus pentoxide, K2O: Potassium oxide, FW: Fresh weight, OM: Organic matter, C: Carbon, RS: Reducing sugar