Responses of Gerbera jamesonii Plants to Different Salinity Levels and Leaching Ratios When Grown in Soilless Culture

This study was carried out to determine the effects of different salinity levels and leaching ratios (LRs) on the growth, yield, quality, and water consumption of gerbera plants grown in soilless culture. Four nutrient solution salinity levels (S0: control; S1: S0 + 1 dS m−1; S2: S0 + 2 dS m−1; S3: S0 + 3 dS m−1) and two LRs (with drainage volumes of 25% of the applied nutrient solution volume (LR25) and 50% of the applied nutrient solution volume (LR50)) were tested in an open soilless culture system during the study which is included two separate production periods. The electrical conductivities (ECs) of the solutions with addition of NaCl to the S1, S2, and S3 treatments were greater than that of the S0 treatment. Gerbera jamesonii cv. ‘Skylina’ was used as the plant material and agricultural perlite was used as the growing medium. The results showed that there was no significant difference between the LRs with respect to yield and flower quality parameters in both growing seasons, whereas the yield decreased dramatically with an increase in salinity. It was found that the highest yield was obtained in the control treatment (S0) in which no additional salt was applied, while the lowest yield was obtained in the highest-salinity treatment (S3) in both growing seasons. Both the number and the weight of the flowers decreased as the salinity of the nutrient solution increased. In particular, a higher LR in saline conditions provided greater yields (i.e., greater flower numbers) in both seasons. This result showed that the LR functioned as an application to reduce the salt effect. In the first and second seasons, the calculated salinity threshold values were 1.4–2.1 dS m−1 for the EC of the nutrient solution and 1.7–2.8 dS m−1 for the EC of the drained solution. It was found that the gerbera plant is moderately sensitive to salinity.