Sustainable approaches for lettuce (Lactuca sativa L.) cultivation: application of biochar, microbial consortia and arbuscular mycorrhizal fungi

This PhD project aims to evaluate the effects of microbial biostimulants and biochar on the growth and quality of Lactuca sativa (variety Icaro), particularly under conditions of environmental stress. Lettuce plants were treated with Rhizophagus intraradices (arbuscular mycorrhizal fungi), biochar derived from wood pellets, and three different bacterial biostimulants. The study focused on assessing plant growth and the accumulation of bioactive compounds such as phenols, flavonoids, and nitrates. Field experiments conducted over two growing seasons showed beneficial effects due to combination of biochar and microbial. The most notable outcomes were observed in the greenhouse experiment under water stress conditions. Here, microbial biostimulants demonstrated their potential to maintain leaf growth and transpiration, even under stress, increasing in phenolic and flavonoid leaf concentrations, as well as overall antioxidant activity. These findings highlight the potential of microbial biostimulants and biochar to enhance plant resilience and nutritional quality, particularly in water-limited environments, contributing to more sustainable agricultural practices.