Walnut shells can improve lettuce quality

A study from the University of Évora reveals that a mix of walnut shells and biochar can replace 20% of coconut fiber in horticultural substrates without affecting lettuce productivity. The research, conducted at the Herdade Experimental da Mitra, also found a 61% reduction in nitrate concentration in lettuce leaves. The study highlights the potential of using crushed walnut shells, a byproduct of the agri-food industry, as a substrate component. The findings suggest that substrate composition can influence both crop productivity and the quality of horticultural products, contributing to circular economy principles and reducing reliance on imported materials. Further research is needed to optimize formulations and irrigation management.