Enhancing Almond Seed Germination and Growth Through Microbial Priming: A Biostimulation Strategy for Sustainable Agriculture

Microbial priming is an emerging strategy in sustainable agriculture that involves the use of beneficial microorganisms to enhance agricultural productivity and sustainability. This innovative approach leverages the natural interactions between plants and microorganisms to promote plant growth and improve soil health. This study explores the application of microbial priming on almond seeds, focusing on the biostimulant effect of soil-based microbial extracts from a mediterranean shrub Pistacia lentiscus L. as an ecological strategy to improve the germination and seedling of almond (Prunus dulcis (Mill.)). The extraction process of soil differentiates three extracts: the first separates AMF spores (Myco) from all other bacterial and fungal consortia (MW), and the third combines the two previous extracts (MW + Myco). The experiment evaluated germination rates, seedling growth parameters, and conducted physico-chemical soil analyses. Arbuscular Mycorrhizal Fungi (AMF) colonization was also measured. Microbial priming significantly improved germination rates and enhanced seedling growth compared to untreated controls. The three microbial extracts showed significant effects on germination rate after 20 days, exceeding 90%. After 27 days, all treatments reach their maximum (100%). Seedling indicators allow MW + Myco extract to be considered as the most powerful extract on almond seedling growth. The combination of microbial and endomycorrhizal fungal extracts could be considered as a facilitator of seedling growth of almond. The AMF colonization was notably higher in treated plants. Overall, microbial priming effectively enhances almond seed germination and seedling growth, demonstrating its potential as a sustainable biostimulation strategy in agriculture. This practice boosts crop productivity and promotes soil health by enriching microbial communities and improving nutrient cycling. These results open up perspectives towards a natural-based strategy able to facilitate the germination and early seedling of almonds in both nurseries and in the field—and to enhance the productivity and health of almond cultivation in special Mediterranean area.