Yield and nutrient use efficiency of lettuce grown at different electrical conductivity levels of hydroponic solutions

In tropical conditions, optimizing electrical conductivity (EC) in hydroponic systems is crucial, as excessive EC can increase saline stress and reduce lettuce growth and nutrient uptake. The study was carried out using randomized block design with four treatments of EC (0.8, 1.3, 1.8, and 2.3 dS m−1) with five replications. EC levels between 0.9 and 1.4 dS m−1 resulted in the highest fresh and dry matter accumulation in both shoots and roots of lettuce. Shoot P, K, Mg, and Fe accumulation and root B accumulation was improved under EC of 0.8 dS m−1. The shoot N, S, Ca, B, Cu, Mn, and Zn accumulation was enhanced with ECs of 1.3, 1.0, 0.9, 1.1, 1.1, 1.4, and 1.5 dS m−1, respectively. In addition, EC 1.3 dS m−1 increased the efficiency of N, P, K, S, Mg, B, Cu, Fe, Zn, and Mn during lettuce cultivation. Thus, EC 1.3 dS m−1 was considered more suitable for lettuce cultivation due to increased leaves yield and shoot accumulation of K, N, Ca, P, Mg, S, B, Mn, Fe and Cu, in addition to increasing N, S, K, B, Zn, Cu, Mn and Fe use efficiency during hydroponic lettuce cultivation.