Measuring and modelling frost damage and termination of white mustard cover crop for conservation agriculture

Cover crops, cultivated for agroecological benefits, must be terminated before sowing the subsequent cash crop. Frost winterkill is a cost-effective, herbicide-free termination method of interest in conservation agriculture, where mechanical termination methods are limited and not always effective. Frost termination depends on interactions between weather and crop development stage, and affects soil nitrogen and water cycles differently from mechanical or chemical termination. Because many interacting factors are involved, simulation models can support cropping system analysis and water, nutrient and weed management decisions. Existing frost damage models developed for cereals have many parameters, limiting their transferability to cover crops. To address this gap, we developed a simplified frost damage model that simulates frost resistance temperature over time, and biomass frost damage after frost events. The model was calibrated using white mustard ( Sinapis alba L.) field data from Lombardy, Northern Italy, and evaluated against a four-year dataset of satellite-derived observations. Under the conditions examined, early sowing maximised biomass production (reaching 3.0–3.5 t DM ha −1 ) and ensured complete frost termination. Conversely, late-sown crops remained in a frost-resistant state and survived sub-zero temperatures down to −5.6 °C. The simulation of frost-damaged biomass had a modelling efficiency of 0.93 on the calibration dataset. After calibration, the model was independently evaluated and predicted first frost damage within the reference frost window with 89% accuracy, while late predictions had a median delay of 3 d. In future work, using broader datasets, its integration in cropping system models will enable decision support under different cover crop management scenarios.