Influence of Nutrient Source and Growing Environment on Tissue Elemental Concentration and Yield of Cos Lettuce in Hydroponic Culture

Complete fertilizers formulated for fertigation and soil application are commonly used in hydroponic production. However, these are unsuitable for hydroponic culture of many crops because of imbalances in mineral nutrient composition. Currently, research information about the effect of nonhydroponic fertilizers and the confounding effects of crop type and culture condition on crop yield is limited. The influence of mineral nutrient source (FERT) and growing environment (two controlled environment hydroponic greenhouses; CEHG) with different temperature and relative humidity (RH) regimes on mineral elemental concentration and yield of cos lettuce (Lactuca sativa L. var. longifolia Lam.), cv. Cimmaron, were determined in a nutrient film technique (NFT) hydroponic culture. With the exception of calcium, both CEHG and FERT had a significant effect on the tissue concentration of all the macronutrients, and the concentration of micronutrients in lettuce tissue were optimum, regardless of FERT and CEHG, except for Fe (APHN and CAMG) and Mo (APHN). However, low tissue concentration of macronutrients may have contributed to reducing the marketable yield, which was also significantly affected by FERT.