How does extended grassland-based dairy production affect energy productivity and GHG emission intensity? Trade-offs in milk-specialised farms

This study examines how the share of grassland shapes the relationship between energy productivity and greenhouse gas (GHG) emission intensity in Polish milk-specialised farms operating under mixed-forage systems. The analysis uses a balanced panel of dairy farms observed from 2014 to 2022 in the Polish FADN database. In the first stage, farm-level GHG estimates are used together with FADN input and output data to construct Hicks-Moorsteen indices of energy productivity change and GHG emission-intensity change. In the second stage, the causal effect of grassland share is identified using the Generalised Propensity Score combined with Generalised Additive Models. The results indicate that energy productivity generally increases with the grassland share, although the effect is non-linear and strongest at very low and very high levels. GHG emission intensity follows a U-shaped pattern: it declines as grassland share rises to around 50%, then increases at higher shares. The findings suggest a synergy zone at moderate grassland shares and a trade-off when pasture-based production becomes too dominant.