Salinity Levels Affecting Growth, Yield and Quality of Strawberry Grown in Peat Bags

Abstract

To estimate the critical salinity level of nutrient solution for strawberry (Fragaria × ananassa Duch.), ‘Nyoho’ plants were grown in peat bags (8 plants in 28 × 80 cm bags containing 18 liter of medium) with solutions prepared with tap water (EC 15 mS/m; Na, 0.35; Cl, 0.29 mM). NaCl (0, 4, 8 and 12 mM) was added to the standard solution containing NO₃-N, 8; NH₄-N, 0.85; P, 0.85; K, 3.8; Ca, 2.05; Mg, 0.93 mM and micro elements. Only the strength of mineral elements, but not that of NaCl, was changed according to the seasons, ranging from 50 to 100% of the standard solution. Concentration of Na and Cl in petiole increased with inclreases in the concentration of NaCl. Total soluble solids and titratable acidity were highest in the control fruit, but the concentration of NaCl did not affect significantly. Severe tip burn occurred in the calyx of the primary flower in plants supplied with 12 mM of NaCl. Average fruit weight and total yield were significantly lower in 12 mM of NaCl compared to the others. The occurrence of tip burn was also stimulated slightly by 8 mM of NaCl, but it only slightly affected the yield. When the EC value of the obtainable water containing NaCl and/or other ions is lower than 100 mS/m, equivalent to 8 mM of NaCl, the water may be available for strawberry production with peat bags.