The efficacy of repeated applications of the urease inhibitor N-(n-butyl) thiophosphoric triamide for improving the efficiency of urea fertilizer utilization on temperate grassland
The effect of N-(n-butyl) thiophosphoric triamide (nBTPT)-amended urea on herbage dry-matter yield and nitrogen offtake by perennial ryegrass (Lolium perenne) was studied in fifteen grassland experiments at two sites in Northern Ireland between 1994 and 1996. The dry-matter yield and N offtake with applied urea was only significantly lower than that with applied calcium ammonium nitrate (CAN) on four occasions. On these occasions nBTPT increased the yield from the application of urea making it almost as effective as CAN. There was no evidence of any adverse effect on grass production with repeated applications of nBTPT-amended urea over a 3-year period and no indication that its efficacy to reduce NH3, loss from ureatreated swards declined when used repeatedly on the same soil.
Document Type: Research Article
Affiliations: 1: School of Agriculture and Food Science, The Queen's University of Belfast, UK 2: Agricultural and Environmental Science Division, Department of Agriculture for Northem Ireland, Belfast, UK
Publication date: 1998-06-01