Chitin and Biochar in strawberry cultivation

Strawberry cultivation is associated with high mineral fertilizer doses and excessive use of chemical plant protection products. Based on previous research, we expected that chitin application to the growing medium will increase the nutrient availability and activate the plant’s systemic defense response, resulting in higher strawberry yields and less disease symptoms. We set up two experiments in which the temporal variability and differences in initial nutrient concentrations of the growing media were taken into account. Chitin induced the plant’s shoot biomass, explained by elevated N concentration in the growing medium and/or the attraction of plant-growth promoting fungal genera towards the plant root, such as Mortierella and Umbelopsis. The over-excessive N concentration and P and K deficiencies in  the chitin treatment led to nutrient disbalances. This may explain the decreased fruit yield and disease resistance of the fruits towards Botrytis cinerea. In contrast, chitin caused a clear defense priming effect of the strawberry leaves, with a strong induction of the jasmonic acid response, resulting in less disease symptoms. Chitin caused positive effects on shoot growth and disease resistance of the leaves, but caution needs to be taken for nutrient disbalances leading to negative influences on fruit production and disease susceptibly. Strawberry plants were grown and harvested under multiple conditions: grown in peat substrate, mock-inoculated,grown in chitin or biochar-enriched peat substrate, mock-inoculated, grown in peat substrate and B. cinerea inoculated or grown in chitin or biochar-enriched peat substrate and B. cinerea inoculated