Amelioration Effects against Salinity Stress in Strawberry by Bentonite–Zeolite Mixture, Glycine Betaine, and Bacillus amyloliquefaciens in Terms of Plant Growth, Nutrient Content, Soil Properties, Yield, and Fruit Quality Characteristics

Strawberry, the most significant berry crop, is characterized as a salt-sensitive plant. The present study aimed to examine ways to alleviate salinity symptoms (34 mM of NaCl in irrigation water) in strawberry plants. For this purpose, the osmolyte glycine betaine was foliarly applied, a mixture of bentonite–zeolite was added to the substrate, and a microbial product based on Bacillys amyloliquefaciens as a soil drench were tested in terms of plant growth and nutrient status, yield, fruit physiological and organoleptic characteristics, as well as phytochemical properties (phenolic compounds, carbohydrates, organic acids, anthocyanins, and antioxidant capacity), and soil physicochemical properties. Salinity severely reduced plant growth and yield, while the effects on fruit quality were also distinct. Treatments alleviated to some extent these negative effects. Plant nutrient content was not severely affected by product application, and neither were most of the soil physicochemical properties. Among the products applied, the mixture of bentonite plus zeolite and glycine betaine proved to be more efficient in ameliorating toxicity symptoms, as both treatments preserved plant hydric status and plant growth, while glycine betaine resulted in an almost 30% higher yield than the treatment with saline water.