Assessing crop production and rotation economically, environmentally and nutritionally in the Republic of Ireland

The importance of finding alternative protein sources to partially replace dietary meat intake has been emphasised. A comparison of different plant-based protein sources, namely cereals (wheat, barley, oats), brassicas (oilseed rape) and legumes (peas, beans), in terms of economic, environmental and nutritional metrics, would help identify optimal strategies for protein production. Due to potential complementarity in a crop rotation production system, including cereals, brassicas and legumes should be investigated as a potential action for stakeholders. This study focuses on the Republic of Ireland, an interesting case study given the limited share of legumes in arable land despite somewhat favourable bio-physical conditions and an increased emphasis on crop rotation financial support under the latest Irish Common Agricultural Policy strategic plan. Our results indicate that legume production is more efficient than oilseed rape and cereal production in terms of greenhouse gas (GHG) emissions and protein yield, but legumes’ gross margin per hectare is less that of cereals. Greenhouse gas emissions per 100 g of protein is also lower for legumes compared to other crops. All scenarios modelled enhanced crop rotations in Ireland and led to an increase in gross margin and protein yield, as well as a decrease in GHG emissions per hectare. Crop rotations including cereals, legumes and brassicas have the potential to support agricultural GHG emissions reduction in Ireland. To realise these benefits, public policies should address the barriers to protein crop production such as the lack of market outlets. Rewarding the agronomic risks associated with legume production should also be emphasised.