Effect of nitrogen form on lettuce plant grown in hydroponic system

Abstract

The responses of grown lettuce plant to different nitrogen forms were evaluated under hydroponic system. Lettuce (Luctuca sativa L.) plants were grown in water culture having 4 nitrogen sources: (a) KNO3and Ca (NO3)2, (b) NH4NO3, (c) (NH4)2SO4or (d) CO(NH2)2. Growth, total nitrogen and nitrates in plants were determined. The NO3-fed plant was somewhat greater in both fresh weight and nitrate content than other plants. In contrast, the NH4- fed plants, showed lower nitrate content and fresh weight than the plants from corresponding three treatments. Total nitrogen content increased, according to applied N form, in the following order: Urea > ammonium sulphate > calcium and potassium nitrate > ammonium nitrate. These differences may be due to the variation in both of the uptake process and assimilation of nitrogen forms in the lettuce plants.