Response of potato (Solanum tuberosum) to nano-DAP based nutrient management under varying phosphorus levels at sub-tropics of North-Western Indian region

Background Low phosphorus (P) use efficiency due to fixation limits potato productivity; therefore, this study evaluated the potential of nano-diammonium phosphate (nano-DAP) to sustain productivity under reduced P inputs. Methods A two-year field experiment (2024–25 and 2025–2026) was conducted at Lovely Professional University, Jalandhar, Punjab, India, under randomized complete block design to compare graded levels of conventional P with and without nano-DAP (seed treatment and foliar application). Agronomic parameters, productivity, nutrient uptake, and stress tolerance parameters were assessed, along with multivariate and FTIR analyses. Results The treatment T 1 1 (75% P through DAP + seed dressing of nano-DAP @ 10 mL L –1 water + two foliar sprays of nano-DAP @ 0.4% at 35 and 55 DAS + 100% recommended N and K) produced significantly higher growth and yield attributes, resulting in substantially higher tuber yield (289.47 q ha –1 ) and biological yield (385.71 q ha –1 ) over other treatments, and remained statistically at par with T 6 (100% P through DAP + 100% recommended N and K) and T 1 2 (100% P through DAP + seed dressing of nano-DAP @ 10 mL L –1 water + one foliar spray of nano-DAP @ 0.4% at 35 DAS + 100% recommended N and K). Conclusion Strategic integration of nano-diammonium phosphate (nano-DAP), i.e. , seed dressing @ 10 mL L –1 + two foliar sprays @ 0.4% at 35 and 55 DAS) with 75% P through DAP improved P use efficiency (agronomic and apparent recovery efficiency) and enabled a 25% reduction in conventional P without yield loss in potato production.