Barley is one of the most important Scottish crops with major economic implications for the Scottish economy because of its use in whisky and beer production. Managing nitrogen (N) fertilizer at field scale for barley is difficult because of the complexity to simultaneously achieve profitability, malting quality and reducing N losses to groundwater. The aim of this study was to model spatial and temporal optimal N fertilizer rates to reduce nitrate leaching while improving grain yield and quality in malting barley. A calibrated and validated crop growth model (DSSAT) was used to identify the optimal amount of N fertilization rates to be applied in the field. The optimal amount of N fertilizer varied between 120 and 140 kg N ha⁻¹ (as average over the 34 years) to maximize the economic return, grain N% and minimize environmental impact. The malting barley premium paid to farmers varies with N content thus affecting marginal net return, with variation ranging from 500 to 2000 GBP ha⁻¹. The use of long-term weather data for the simulations allowed the calculation of outcomes from 34 different growing seasons. This information combined with the different premium levels paid to farmers can be helpful in identifying the possible combinations between grain quality premium-N fertilizer-weather conditions. Modelling the long-term data showed that the simulated N leaching (kg N ha⁻¹) was highly variable between years and the greatest trade-off was for the amount of N leached. The overall the applied N fertilizer rate had a strong effect on the risk of a trade-off developing over the 34 different growing seasons.

大麦是苏格兰最重要的农作物之一，因为它在威士忌和啤酒生产中的应用对苏格兰经济具有重要的经济意义。大麦难以在田间规模上管理氮肥，因为要同时实现盈利，制麦质量和减少氮素对地下水的损失非常复杂。这项研究的目的是模拟时空最佳氮肥用量，以减少硝酸盐的淋失，同时提高大麦麦芽的谷物产量和品质。使用经过校准和验证的作物生长模型（DSSAT）来确定要在田间施用的最佳氮肥施用量。最佳氮肥用量在120至140 kg N ha ^-1之间（在过去34年中的平均值），以实现最大的经济回报，N％的谷物含量以及对环境的影响最小化。向农民支付的麦芽大麦保费随氮含量的不同而变化，从而影响边际净收益，变化范围为500至2000英镑ha ^-1。使用长期天气数据进行模拟可以计算来自34个不同生长季节的结果。该信息与支付给农民的不同溢价水平相结合，有助于确定谷物质量溢价-N肥料-天气状况之间的可能组合。长期数据建模表明，模拟的氮淋失（kg N ha ^-1）在几年之间变化很大，最大的折衷是浸出的N量。总体而言，氮肥施用量对34个不同生长季节中权衡风险的发展产生了重大影响。