The management of climate-resilient grassland systems is important for stable livestock fodder production. In the face of climate change, maintaining productivity while minimizing yield variance of grassland systems is increasingly challenging. To achieve climate-resilient and stable productivity of grasslands, a better understanding of the climatic drivers of long-term trends in yield variance and its dependence on agronomic inputs is required. Based on the Park Grass Experiment at Rothamsted (UK), we report for the first time the long-term trends in yield variance of grassland (1965–2018) in plots given different fertilizer and lime applications, with contrasting productivity and plant species diversity. We implemented a statistical model that allowed yield variance to be determined independently of yield level. Environmental abiotic covariates were included in a novel criss-cross regression approach to determine climatic drivers of yield variance and its dependence on agronomic management. Our findings highlight that sufficient liming and moderate fertilization can reduce yield variance while maintaining productivity and limiting loss of plant species diversity. Plots receiving the highest rate of nitrogen fertilizer or farmyard manure had the highest yield but were also more responsive to environmental variability and had less plant species diversity. We identified the days of water stress from March to October and temperature from July to August as the two main climatic drivers, explaining approximately one-third of the observed yield variance. These drivers helped explain consistent unimodal trends in yield variance—with a peak in approximately 1995, after which variance declined. Here, for the first time, we provide a novel statistical framework and a unique long-term dataset for understanding the trends in yield variance of managed grassland. The application of the criss-cross regression approach in other long-term agro-ecological trials could help identify climatic drivers of production risk and to derive agronomic strategies for improving the climate resilience of cropping systems.

气候适应型草原系统的管理对于牲畜饲料的稳定生产非常重要。面对气候变化，在保持生产力的同时最大限度地减少草地系统的产量差异变得越来越具有挑战性。为了实现草原的气候适应能力和稳定生产力，需要更好地了解产量差异长期趋势的气候驱动因素及其对农业投入的依赖性。基于英国洛桑的公园草地实验，我们首次报告了不同肥料和石灰施用情况下草地产量方差的长期趋势（1965-2018），并对比生产力和植物物种多样性。我们实施了一个统计模型，允许独立于产量水平确定产量方差。环境非生物协变量被纳入一种新颖的交叉回归方法中，以确定产量差异的气候驱动因素及其对农艺管理的依赖性。我们的研究结果强调，充足的石灰和适度的施肥可以减少产量差异，同时保持生产力并限制植物物种多样性的丧失。施氮肥或农家肥比例最高的地块产量最高，但对环境变化的反应更灵敏，植物物种多样性也较低。我们将 3 月至 10 月的缺水天数和 7 月至 8 月的气温确定为两个主要气候驱动因素，解释了观察到的产量差异的大约三分之一。这些驱动因素有助于解释产量方差的一致单峰趋势——大约在 1995 年达到峰值，之后方差下降。在这里，我们首次提供了一个新颖的统计框架和一个独特的长期数据集，用于了解管理草地产量方差的趋势。在其他长期农业生态试验中应用交叉回归方法可以帮助确定生产风险的气候驱动因素，并得出提高耕作系统气候适应能力的农艺策略。