Various ammonium salts, urea, aqua ammonia, and anhydrous ammonia are important sources of nitrogen for the fertilization of agricultural crops. While ammonia and its compounds are useful as fertilizers, they can be, and often are, toxic to many plants (Willis and Rankin, 1930; Stout and Tolman, 1941; Raleigh, 1942; Stoll, 1954; Lorenz, 1955; Grogan and Zink, 1956; Allen, 1962; Cooke, 1962; Allred, 1963; Court et al, 1964; Hood and Ensminger, 1964). There are also products which have been designed to retard the oxidation of ammonia and its compounds (Go ring, 1962). It is therefore important that the effects of ammonia and its compounds on plants, plant growth and plant metabolism be fully understood
