The evaluation of urea as a nitrogen fertilizer on wheat

Nitrogen fertilization has become an important farming practice in the past seventy five years. During the latter part of the nineteenth Century the use of sodium nitrate increased rapidly in Europe and America (3). Shortly after 1893 ammonium sulfate, a by-product of the coke industry, appeared on the American market.

Urea, imported from Germany, was used to a limited extent from 1924 to 1936, primarily in the preparation of commercial, mixed fertilizers. A product having the name Urason was placed on the market in 1938. It consisted of urea treated with cocoa shell meal rock phosphate dust which coated the individual particles. Since World War II the production of nitrogen fertilizers has increased rapidly, and today there are many products available including urea fertilizers which have appeared under trade names such as Floranid, Urear, Calsi-Urear, and Agramon (15).

While some studies have been made of urea as a nitrogen fertilizer, there is much to be learned of its behavior in soils and its relative efficiency under different soil and crop conditions. The purposes of this investigation have been:

(1) To evaluate urea as a nitrogen fertilizer on wheat under several soil conditions in Tennessee, and

(2) To determine rates of urea conversion to ammonia and nitrate and to determine the influence of certain factors which affect this conversion.