The decomposition of crotonylidene di-urea in soil and the recovery of nitrogen by ryegrass

Abstract

SUMMARYCrotonylidene di-urea (CD-urea) in a sandy-loam and two clay-loam soils decomposed slowly at 7°C, and from 8 to 15% was recovered as mineral-N after 24 weeks. At 25°C, it decomposed faster in the sandy-loam than the clay-loam soils; with 100 ppm N, a maximum of 86% was recovered after 16 weeks, and 80% of 1000 ppm N after 24 weeks. Recovery after 24 weeks ranged from 30 to 60% in the clay loams.Ryegrass grown in pots produced more extra dry matter, containing more N, during 16 weeks when given ammonium sulphate than it did during 50 weeks with CD-urea.