Fluid nitrogen fertilizers for direct application in the United States

Abstract

The potential of ammonia as a lower cost source of nitrogen was first realized in California in the early 1930s when ammonia gas was added to irrigation waters. Direct injection followed in 1939. Increased availability of ammonia gas after the Second World War provided the impetus to subsequent commercial development. The agronomic and economic implications of pressure and non-pressure systems and the practical significance of nitrogen source are discussed in detail.