Polysulphate application significantly increases lettuce fresh and dry biomass, and increases Ca and S concentrations in the leaves.
Northern R&D Farm, Israel.
To evaluate Polysulphate as calcium source for lettuce, using a greenhouse soilless production system.
The experiment was designed in complete random blocks, with six replicates consisting of five pots each. Plants were grown under controlled greenhouse conditions in 4 L pots filled with perlite. Treatments included four rates of granular Polysulphate: 0 (control), 0.25, 0.50, and 0.75 g/L that were thoroughly mixed with the perlite before planting.
Water used for irrigation was desalinated using reverse osmosis to a level of 0.6 mEq Ca/L. Plants in all treatments were fertigated throughout the experiment with NPK 5:3:8 + MgSO4. Irrigation was scheduled three times a day for 10 minutes per irrigation (approx. 1 L/day).
- Polysulphate application significantly increased lettuce fresh and dry biomass, adding up to 25% to the fresh weight of the plants.
- Ca and S concentrations in the leaves were significantly higher with Polysulphate application, but no response was observed to the nutrient dose.
- Polysulphate application can ensure enough available Ca to satisfy lettuce requirements and guarantee high produce quality.
Similar letters indicate no significant differences between treatments at p <0.05.