The Effect of Foliar Fertilization with Different Doses of Nitrate Sources on Yield, Nitrate Accumulation and Cost of Lettuce (Lactuca sativa L.)

Abstract

The aim of this study was to determine effect of additional foliar fertilization with different doses of nitrate sources on yield, nitrate accumulation and cost of lettuce (Lactuca sativa L.) in field conditions. A summer heat resistant crisphead lettuce (cv. ‘Bohemia F1‘) was used as plant material. Also urea (CO(NH2)2), potassium nitrate (KNO3) and calcium nitrate (Ca(NO3)2) were used as additional foliar fertilization with doses of 0.4%, 0.6% and 0.8%. Total nitrogen values of lettuce leaves ranged from 2.20% (KNO3 0.4%) to 3.00% (Urea 0.8%). The highest nitrate accumulation was determined with 0.8% application of Ca(NO3)2 with 2610 mg kg-1, while the lowest nitrate accumulation was determined with 2070 mg kg-1 only in base fertilization (NH4NO3). As a result of additional foliar fertilization with different nitrogen sources, it was determined that the highest yield values were 4926 kg da-1 (Urea 0.6%), 4787 kg da-1 (Urea 0.8%) and 4719 kg da-1 (Ca(NO3)2) in lettuce, respectively. However, considering the fertilizer costs in the research where the other agricultural inputs are the same, in the profitability analysis, the highest profit was determined in additional foliar fertilization with different doses of urea (0.6%) due to its low cost compared to other fertilizers. According to the results of the research, when the profitability is taken into consideration, it can be clearly said that the treatments with urea are more suitable and recommendable additional foliar fertilization for both high yield and more profit.