POTENTIAL NITRATE LEVELS IN EDIBLE PLANT PARTS

Abstract

Over 25 important vegetables were grown at low to high rates of nitrogen fertilization, and their potential to accumulate nitrates determined. Leaf and stem tissues accumulated the highest levels of nitrate, followed by the roots. Fruits and floral parts accumulated only small amounts of nitrate. Some nitrate accumulation is a natural and necessary process and the levels of nitrate in the plants cannot be reduced much without reducing yield. The stage of maturity of the produce at harvest had little effect on nitrate accumulation. Differences in nitrate levels between cultivars of the same species were generally small. Nitrate accumulation increased as the rate of nitrogen fertilization increased. Nitrate sources of fertilizer resulted in higher nitrate accumulation than did ammoniacal sources. Even at the highest rates of nitrate accumulation observed, the possibilities of an adult consuming enough food to cause nitrate toxicosis are exceedingly remote. The levels of nitrate currently found in food pose no major health hazards to human adults.