Response to nitrogen of three annual grasses

Abstract

The responses of three annual grasses (Lolium rigidum, Vulpia myuros, and Hordeum leporinum) to nitrogen fertilizer were studied at three densities. Total herbage and nitrogen uptake were measured at four harvest dates. The response of the three grasses to nitrogen depended on their density. At low density both Lolium and Hordeum had greater dry weight increase than Vulpia, but at high density Vulpia responded as well as Lolium and better than Hordeum. By comparing the nitrogen responses at similar amounts of available herbage it was seen that, over a wide range of availability, both Lolium and Vulpia had greater absolute response than Hordeum. It was concluded that nitrogen response would probably be greatest on swards of Lolium or Vulpia that have a particular amount of available herbage.