Forage brassicas have historically been used in high rainfall/irrigated temperate livestock systems, but there is increasing interest in diverse forage brassicas in drier mixed crop-livestock farming systems. Computer-based modelling is an important decision support tool used in agriculture to explore the adaptability of crops to different climates and agronomic management practices, but existing modelling tools for forage brassicas are limited to temperate environments. We parameterised the APSIM (Agricultural Production Systems Simulator) model for four forage brassica genotypes, including three diverse forage rape cultivars and a raphanobrassica. The model was calibrated using two experiments with repeated measures of biomass components, nutritive value, and leaf and canopy development. We then tested the model extensively using data from a diverse set of environments within Australian and New Zealand (23 sites across four agro-climatic zones). Model predictions of biomass were good for all the genotypes (NSE > 0.60, Nash-Sutcliffe efficiency; RMSE ~1.5 t DM/ha, root mean square error). Predictions of metabolisable energy yield were satisfactory for all genotypes (NSE 0.43–0.73; RMSE ~17.8 GJ ME/ha) but forage dry matter digestibility (DMD) were poorly predicted due to the small variation in observed data. Our robust and widely tested model can be confidently used to predict forage productivity of common and new forage brassicas across a wide range of production environments and agronomic management practices. This model will enable future work to develop a better understanding of the potential value of these important forage crops for livestock production systems.

饲料芸苔属植物历来用于高降雨量/灌溉温带畜牧系统，但在干燥的作物-畜牧业混合养殖系统中，人们对多样化的饲用芸苔属植物越来越感兴趣。基于计算机的建模是农业中用于探索作物对不同气候和农艺管理实践的适应性的重要决策支持工具，但现有的草料芸苔建模工具仅限于温带环境。我们为四种草料芸苔基因型参数化了 APSIM（农业生产系统模拟器）模型，包括三种不同的草料油菜品种和一种萝卜。使用重复测量生物量成分、营养价值以及叶和冠层发育的两个实验来校准该模型。然后，我们使用来自澳大利亚和新西兰不同环境的数据（跨越四个农业气候区的 23 个地点）对模型进行了广泛的测试。生物量的模型预测对所有基因型都有好处（NSE > 0.60，Nash-Sutcliffe 效率；RMSE ~1.5 t DM/ha，均方根误差）。所有基因型的可代谢能量产量的预测都令人满意（NSE 0.43-0.73；RMSE ~17.8 GJ ME/ha），但由于观察数据的微小变化，草料干物质消化率（DMD）的预测很差。我们强大且经过广泛测试的模型可以自信地用于预测各种生产环境和农艺管理实践中常见和新草料芸苔的草料生产力。