Hay production in Sicily: Life Cycle Assessment of a case study across two seasonal yields

Hay production is essential for livestock farming with Italian forage crops covered approximately 6 million hectares in 2023. However, forage production is highly sensitive to climatic variation, which can significant-ly affect yields, increasing the environmental pressure per unit of product.This study employs Life Cycle Assessment (LCA) to assess the environmental impacts of mixed hay pro-duction from different mediterranean forage species. Data were collected from a farm located in Cam-marata (AG), Sicily, over two growing seasons: a high-yield (HY) season in 2021-2022 and a low-yield (LY) season in 2023-2024. A “cradle-to-gate” system boundary was defined, covering the production and transport of inputs and field operations up to hay bale transport to the barn. Two distinct functional units (FUs) were employed: yield-scaled (ton of hay) and area-scaled (hectares of cultivated land). The LCA, performed using SimaPro 9.5.0.2 and the CML-IA baseline V3.09 / EU25 method, revealed that the choise of FU had a significant influence on the interpretation of environmental performance. In the LY season, impacts per tonne of hay were approximately 70% higher than in the HY season due to lower yields. However, when assessed per hectare, the difference was around 20%, with slightly higher impacts in the HY season, suggesting that agronomic practices remained consistent, and environmental pressure per unit area did not change significantly. Marine Aquatic Ecotoxicity per yield-scaled FU increased from 2.66E+05 (HY) to 1.02E+06 (LY) kg 1,4-DB eq. Similarly, GWP100a increased by a factor of 3.3, rising from 155 kg CO2 eq in the HY season to 512 kg CO2 eq in the LY season, reflecting higher input requirements and increased emissions per unit of biomass. Normalization of results showed the previous categories as the most affected, representing the primary areas of concern. Adaptive strategies will be essential for ensuring sustainable hay production while main-taining productivity.