The Influence of Fertilizer on Nitrate, Nitrite and Vitamin C Contents in Vegetables

Abstract

The aim of this study was to examine the influence of fertilization on nitrate, nitrite, and vitamin C contents in vegetables. All seedlings (mustard, bokchoy, spinach, and lettuce) were grown in the greenhouse in polybags with organic and inorganic fertilizers. Nitrite was derivitized with sulfanilic acid and N-(1-naphthyl) ethylenediamine dihydrochloride in acetic acid solution, then absorbance measured by spectrophotometer at 540 nm. Nitrate reduced to nitrite by adding zincum powder in acidic condition, then determined as nitrite. Vitamin C was titrated with 2,6-dichlorophenol indophenol.The study show that the influence of organic fertilizers increased nitrate, nitrite and vitamin C contents with increasing doses. Inorganic fertilizers was found to be more influential to increase nitrite and nitrate contents, but decreased vitamin C with increasing doses.This findings suggest that inorganic fertilizers more effective to increase nitrate and nitrite contents compared to organic fertilizers. Organic fertilization increased vitamin C, but inorganic fertilization decreased.