The effects of soil temperature on urea hydrolysis, nitrification, and plant utilization

Urea is being produced in large amounts for use in plastics, feeds and fertilizers. Although it has been used as a fertilizer for many years, it has not been until recent years that adequate supplies have been available for extensive use as a fertilizer. It was the purpose of this investigation to study some of the factors that influence the availability of urea nitrogen to plants. The two main objectives of this study were: (1) to determine the rate of urea hydrolysis subsequent nitrification to nitrate nitrogen at several controlled soil temperatures, and (2) to determine the yield and chemical composition of ryegrass forage grown under controlled conditions with different rates of nitrogen fertilization from urea and ammonium nitrate.