If an excess of nitrogen is present in the soil, the nitrate content may be too high, particularly if some other essential nutrient is not adequate. Vegetables produced on high organic soils, and even where no fertilizer nitrogen is applied, frequently have a higher nitrate content than the same species grown in Missouri with soil nitrogen treatment. Nitrate-nitrogen values are given in Table 5 to demonstrate the range for a given vegetable. Tomatoes with vigorous foliage are usually low in nitrate content. However, where the plant is defoliated by disease, weather or other factors, the nitrate from the soil may move directly to the fruit and accumulate.
Conversion factors Several expressions are frequently used with reference to nitrogen.
Table 6 includes those commonly used and provides a ready reference in making conversions from one expression to another. Copyright 1999 University of Missouri. Published by University Extension , University of Missouri-Columbia. Ronald J. Turner, Director, Cooperative Extension Service, University of Missouri and Lincoln University, Columbia, Missouri 65211. University Extension does not discriminate on the basis of race, color, national origin, sex, religion, age, disability or status as a Vietnam-era veteran in employment or programs.