Biochar and Drying Technologies as Integrated Tools for Sustainable Pea Production and Functional Ingredient Generation

The growing demand for sustainable agriculture requires strategies that simultaneously recover soil quality, improve crop yield, and add value to food products. This study evaluates walnut shell biochar (450 °C) as a circular amendment applied at 0, 10, and 20 t ha −1 to an arid soil cultivated with pea ( Pisum sativum L. cv. Onward) in San Juan, Argentina. Biochar enhanced soil porosity, respiration, organic carbon, and cation exchange capacity, resulting in higher plant biomass and a 30.9% increase in pod yield for the 20 t ha −1 treatment. Pea grains were dehydrated by far-infrared drying at 70 °C, producing flour with improved lipid content, water absorption, and swelling capacity, which increased from 0.21 to 0.26 mL g −1 under the 20 t ha −1 treatment. The combined use of biochar and controlled drying highlights a viable pathway to close the soil–plant–food loop through resource valorization. This work contributes practical evidence of biochar’s multifunctional role in sustainable agri-food systems, aligned with circular economy principles.