Effect of organic ferti̇li̇zer use on salt stress tolerance in lettuce

In this study investigating the effectiveness of organic fertilizer applications for increasing salt tolerance in lettuce, Caipira (Şakira) curly lettuce variety (Batavia type) was used as material. Seedlings were planted in peat:perlite mixture and vermicompost, barnyard manure and humic acid were applied to the pots during planting. For stressed plants, 100 mM NaCl (salt) dose was applied 18 days after planting the seedlings. Plants harvested at the end of stress were examined in terms of green parts, fresh and dry weights, plant height, girth and crown width, root collar diameter, leaf area, total yield, relative water content (YOSİ), SPAD value, green parts Na, Cl, K and Ca contents. Salt stress caused a decrease in plant growth parameters, SPAD value, total yield, YOSİ, K, and Ca contents; while there was an increase in TSS, Na and Cl ion concentrations. On the other hand, in organic fertilizer applications together with salt stress, on average, 66-102% improvement was achieved in fresh and dry weight; 4-42% in plant height and root diameter; 29-70% in plant circumference and crown width; 140-208% in leaf area, 40-63% in total yield; 35-49% in YOSI values; 24-45% in K content; 14-59% in Ca content compared to salt stress. In addition, Na ion uptake was limited to 17-24%, Cl ion uptake was limited to 7-15%. As a result of the study, it was determined that organic fertilizer applications improved the damage caused by salt stress at varying rates and were effective in increasing tolerance, and among the applications, vermicompost and barn manure applications came to the fore in terms of this positive effect.