Abstract
An experiment was performed to evaluate the effect of Trichoderma harzianum MVT801 combined with different ratios of nutrient solution (NR) (25%, 50%, and 100%) on the growth and physiological traits of Lactuca sativa "Lollo Rosso" plants cultivated in floating systems. Inoculation of lettuce plants with T. harzianum MVT801 (T(1)) in a floating system improves biometric properties, photosynthetic parameters, and nutrient uptake compared with uninoculated treatment (T(0)). The results clearly showed that in T(1), despite a 50% reduction in the ratio of nutrient solution, no significant difference was observed in the growth and photosynthesis characteristics and nutrient uptake in L. sativa "Lollo Rosso" leaves compared with a complete nutrient solution treatment (100%), which is one of the notable results of this study. In this regard, the highest yield was observed in T(1)NR(50) (inoculated with fungi and 50% of the nutrient solution) and T(1)NR(100) (inoculated with fungi and complete nutrient solution) treatments. Also, the highest concentrations of phosphorus and potassium in "Lollo Rosso" leaves were observed in T(1)NR(50) and T(1)NR(100) treatments. Accordingly, the use of T. harzianum in floating lettuce cultivation could be recommended to increase crop productivity and reduce the use of chemical fertilizers.