Benefits of using silicon as a nutrient in sustainable strawberry production

Silicon is not considered an essential plant element and strawberries are not considered to be silicon accumulators. However, work at the University of Hertfordshire shows that the use of a bioavailable silicon nutrient has multifaceted benefits on strawberry plants. Field experiments (2012-2018) on a commercial strawberry farm at Wisbech, UK, consistently showed that weekly application (spray or root via the fertigation system) of the silicon nutrient at a concentration of 0.017% (volume/volume) on strawberries reduced the severity of strawberry powdery mildew (Podosphaera aphanis), regardless of cultivar. Silicon also delayed the epidemic build-up in the silicon nutrient alone treatment for up to 14 days when compared with untreated control. Reductions in the severity of two-spotted spider mite (Tetranychus urticae) on strawberries (P<0.05) were also observed (2014 and 2015). Glasshouse hydroponic (in Hoagland's solution) experiments (2018 and 2019) investigating silicon deficiency and toxicity showed that weekly application of 0.017% (v/v) silicon nutrient on strawberries resulted in more leaves and fruits, higher chlorophyll content, and higher Brix levels in the fruit (P<0.05); no classic deficiency symptoms were observed in untreated plants, however, there was stunting compared with silicon treated plants. The weekly application of 1.7% (v/v) silicon nutrient was found to have toxic effects on plants but no albinism was observed. Silicon was found mainly deposit in the leaf cuticle, epidermis and palisade layers; it resulted in increased cuticle thickness and the density of leaf wax, enhancing the passive defence pathway. The silicon nutrient is not essential but has stimulatory effects on strawberry growth; it protects plants against disease and pests, thus reducing pesticide usage, and making a valuable contribution to sustainable strawberry production.