Informing the prediction of forage quality of Mediterranean grasslands using hyperspectral reflectance: Concentration vs content, phenology, and generalisation of models

Remote sensing has shown potential to provide accurate and real-time information on grassland forage quality, crucial for the management of livestock systems. However, there are still uncertainties that must be considered to make models reliable and practical. A source of discrepancy regards the measurement unit describing forage quality variables, namely either mass-based concentration (%) or mass per surface area content (kg ha−1). Furthermore, phenological patterns largely influence grassland reflectance and have a strong impact on model accuracy. Also, the generalisation of empirical models in heterogeneous grasslands can hinder their applicability.