Techno-Economic (TEA) and Environmental (LCA) Assessment of Hulless and Hulled Oat Production Under Different Nitrogen Fertilization and Plant Protection Regimes

This study provides an integrated techno-economic (TEA) and environmental life cycle assessment (LCA) of 18 oat production technologies based on three-year field trials (Bałcyny, north-eastern Poland, 2017–2019). The design evaluated two oat morphotypes (hulled cv. Nawigator vs. hulless cv. Nagus) across three nitrogen fertilization levels (0, 60, and 120 kg N ha−1) and three plant protection regimes (untreated control, herbicide, herbicide + fungicide). To ensure commercial representativeness (ISO 14044), experimental yields were scaled to regional production levels (k=0.686). The functional unit was 1 kg of grain, supplemented by an area-based (per hectare) perspective. Moderate nitrogen fertilization (60 kg N ha−1) achieved the most balanced eco-efficiency profile, combining peak net margins (EUR 108 ha−1 for hulled oats with herbicide and EUR 72 ha−1 for untreated hulless oats) with minimal greenhouse gas emissions (0.24 and 0.31 kg CO2-eq kg−1, respectively). Increasing nitrogen to 120 kg N ha−1 induced diminishing economic returns and elevated eutrophication and acidification, despite improving land-use efficiency. The addition of a fungicide escalated freshwater ecotoxicity by 9- to 11-fold without yield benefits under moderate disease pressure. Due to a 40% higher grain yield, hulled oats exhibited superior cost dilution and lower environmental footprints per kilogram than hulless oats. These findings demonstrate that sustainable cereal production relies on intermediate input optimization rather than yield maximization.