Just the right amount of nitrogen ensures safer lettuce

The discussion about nitrate accumulation in hydroponic lettuces gained new momentum after the release of data by Ítalo Guedes, an agricultural engineer and researcher at Embrapa, highlighting how different proportions of NO3? and NH4? influence the growth and quality of the leaves. The information comes from a study conducted in a container farm, in a DFT system and with complete environmental control, including an average DLI of 14.5 mol m² day, which allowed for an accurate evaluation of the plants' response to different forms of Nitrogen. According to the data presented, the increase in the proportion of nitrate in the nutrient solution consistently raised the NO3? content in the sap and leaves. Nevertheless, the levels remained below the limits of European legislation, a relevant point for productions in fully controlled environments, such as automated greenhouses and vertical farms. Concentrations higher than 15 percent of N-NH4? resulted in a drop in productivity, lower ...