Urea leaching in a sandy soil

Abstract

An experiment was developed to provide quantitative information about the leachability of urea per se. In order to make the study more complete, the movement of the hydrolytic products of urea was also determined. Comoro fine sandy loam columns with lengths of 30, 61, and 91 cm were fertilized with ¹ ⁵N-labelled urea and irrigated immediately with 10 cm of a leaching solution. Chemical analyses of the soil from the columns were performed after three, five, and six days respectively. Chemical analyses of increments of leachate were also done. A gamma-ray column scanner was used for moisture studies of the columns. It was found that all of the urea hydrolyzed or was immobilized within three days. The hydrolytic products accumulated mainly between 15 and 45 cm in depth. Approximately 50 percent of the added urea was immobilized within six days, and approximately 50 percent was found as nitrates in the 91 cm columns at the end of six days.