THE YIELD, NITROGEN AND NITRATE CONTENT OF REED CANARYGRASS, MEADOW FOXTAIL AND TIMOTHY FERTILIZED WITH NITROGEN

Abstract

The effects of five rates of nitrogen (N) fertilizer applied in the spring and four rates of N applied in the spring and after each harvest were determined on yield, percent N and nitrate accumulation in timothy (Phleum pratense L.), reed canarygrass (Phalaris arundinacea L.) and meadow foxtail (Alopecurus pratensis L.) for 4 yr. The three grass species were grown on a fine clay soil at Prince George, B.C. Meadow foxtail, reed canarygrass and timothy yields increased up to 5.0, 5.3 and 2.3 times, respectively, with spring-applied fertilizer. Yields of timothy were significantly higher than the other two species when no N was applied. Nitrogen content increased with increasing rates of applied N for the three grass species. Nitrate content measured as nitrate-nitrogen (NO3-N) increased with increasing N rates. Meadow foxtail accumulated the highest levels of NO3-N and reed canarygrass intermediate levels. The NO3-N content of timothy was always less than the minimum safe level of 0.15% NO3-N even at the highest N application rates. This minimum safe level was exceeded most often by meadow foxtail and sometimes by reed canarygrass.Key words: Yield, nitrogen, nitrate, reed canarygrass, meadow foxtail, timothy