Nano-enabled fertilization alters nitrogen release dynamics and improves fertilizer use efficiency by reducing volatilization and leaching losses: Insights from 15N tracing and kinetic modelling

Abstract

Inefficient nitrogen (N) management in agroecosystems is largely driven by rapid nutrient release and substantial losses from conventional urea fertilizers, resulting in low nitrogen use efficiency (NUE) and environmental concerns. This study evaluated the ability of nano-enabled fertilization to regulate N dynamics to better synchronize N availability with crop demand. An integrated framework combining soil incubation, ammonia volatilization, nitrate leaching and 15N isotopic tracing was employed to quantify N transformation, loss pathways and plant uptake. The results revealed that conventional urea exhibited rapid N release, reaching peak available nitrogen concentrations of 183.4 mg kg-1 within 3 weeks, whereas nano urea treatments delayed peak nitrogen availability to 6–7 weeks, indicating a sustained release pattern. This behaviour was supported by kinetic modelling, where first-order release rate constants were markedly lower under nano urea (0.115–0.151 week-1) than under conventional urea (0.664–0.753 week-1), confirming slower and more controlled nitrogen release The sustained release significantly reduced ammonia volatilization loss by 53% (11.7 vs 24.7 mg kg-1) and nitrate leaching at 30 cm depth by 39% (81 vs 133 mg kg-1) under nano urea treatments compared to conventional urea under controlled conditions. Moreover, the application of integrated treatment (75% conventional urea as soil application + two foliar sprays of nano urea at critical growth stages of maize) achieved the highest total N uptake (2909.14 vs 2556.92 mg plant-1) and enhanced NUE (46.47 vs 44.21%) compared to sole urea application. Therefore, these findings suggested that nano-enabled fertilization regulates N release kinetics, reduces loss pathways and improves NUE by enhancing temporal synchronization between N availability and plant demand.