Context: Nitrogen (N) management in Australian broadacre dryland cropping systems is challenged by high climate variability and thus uncertain seasonal outcomes. Growers struggle to anticipate the seasonal crop N demand, applying conservative fertilizer N rates that trade upside yield and profit margin in favourable seasons for reduced risk of economic loss in unfavourable seasons. Strategic N banking is a strategy for stabilizing N supply from soil and fertilizer across seasons at an environmentally appropriate target. It reduces the complexity of seasonal N planning, increases resilience against climate variability and maximizes water-limited yields and profit across seasons. However, environmentally appropriate N bank targets are likely to vary among crop rotations, soil, and climatic conditions that occur across Australia's dryland cropping regions. Objectives: The study aimed to 1) identify optimal N bank targets across diverse production environments, 2) characterize the biophysical drivers of crop response to N banking, and 3) evaluate implications of N banking for grower decision-making. Methods: Long-term APSIM simulations were conducted across 3750 representative soil-climate-rotation combinations spanning Australian grain regions. Four optimal N bank targets were estimated based on productivity, profitability, and environmental net benefits (costing N losses). Biophysical drivers of crop response to N banking were analysed using regression tree and spatial analysis. Results & discussion: Optimal N bank targets varied widely but consistently maintained small positive N balance (similar to 30-80 kg N ha(-1) over 32 years), maximizing gross margins while maintaining near-neutral system N balances. Shadow cost analysis revealed substantial opportunity losses (-$500 to -$90 ha(-1)) under conservative farmer-average approaches while well-targeted N banking was only marginally worse-off (-$45 ha(-1)) than optimal annual N supply. Furthermore, the analyses showed that environmentally and economically optimal N bank targets were largely similar, with the environmental optimum not reducing productivity while consistently mitigating trade-offs between net benefit and environmental outcomes. Significance: Regionally tailored N bank targets offer a scalable, climate-resilient strategy to optimize N inputs, reduce environmental risks and support long-term crop productivity.