Responses of potato to different methods of zinc and boron application in midhills of Nepal

Zinc (Zn) and boron (B) are important micronutrients for potato production and they play a critical role to achieve the potential yield. This research was conducted to evaluate the effects of the foliar and soil application of Zn, B, and agriculture lime in enhancing potato (cv. Khumal Bikash) yield and size of tuber. The experiment was conducted for two consecutive years (2022 and 2023) at the National Potato Research Program, Khumaltar, Nepal. Seven fertilizer treatments, namely T1: recommended dose of NPK (RDF); T2: RDF+ Zn+ B; T3: RDF +B +Ag-lime; T4: RDF +Zn +Ag-lime; T5: RDF +Zn +B +Ag-Lime; T6: RDF +(Z +B) foliar Spray; T7: RDF + foliar Spray (2% urea +2% K) were arranged in a randomized complete block design. Foliar spray was applied twice, once at 40 DAP and again after 60 DAP. Ag-lime was applied before 15 DAP. Among seven treatments, T6 (RDF +Zn +B foliar spray) showed a significant effect on yield (31.84 t/ha) and its variables including vigor, uniformity and ground cover of potato followed by T5 (28.81 t/ha) and T7 compared to the treatments without Zn and B. Foliar application of mixture of Zn and B (3 kg Zn/ha + 2 kg B/ha) significantly improved germination, vigor, sizes and number of tuber and total yield compared to a separate application of Zn or B. The treatment T6 (RDF + Zn + B foliar) demonstrated the highest micronutrient efficiency (1494 kg ) highlighting the superior effectiveness of foliar application compared to other treatments. These findings suggest that micronutrients Zn and B is important to increase potato tuber yield and maximum benefits could be achieved with the foliar application at 2 splits.