Influence of source, time and method of application, and simulated rainfall on recovery of nitrogen fertilizers applied to bromegrass

摘要: Four field experiments were conducted in central Alberta to determine influence of the N source, time and method application simulated rainfall on recovery of15N-labelled fertilizers applied meadow bromegrass (Bromus biebersteinii Roem Shultz. cv. Regar) plants (topgrowth plus roots) soil. The first experiment compared two sources (urea ammonium nitrate (A.N.)) six times (early fall, late early winter, spring, spring spring-summer split) where surface-broadcast. Urea gave lower than A.N., regardless (on average by 16.4% 18.3% soil). For urea, higher other application, especially at Eckville site. applications fall or winter but was only slightly greater with application. second evaluated methods placement (surface-broadcasting banding). increased subsurface band over surface-broadcast 20.2% for 15.5% investigated effect amount (0, 5, 10, 20 40 mm) interval 1, 2, 4, 8, 16 d) between surface urea recovery. Simulated 10 mm immediately after moist soil 8.1–10.7% no rainfall. Delaying (20 4 d decreased 8.7–15.2%. In conclusion, improved greatly when placed below