THE EFFECT OF NITROGEN-FERTILIZER ON THE GROWTH OF BROMUS-STERILIS IN-FIELD BOUNDARY VEGETATION

Results from the first 3 years of experiments investigating the effect s of mis-application of nitrogen fertiliser to hedgebank vegetation ar e reported. Rates of fertiliser were chosen to simulate amounts which may be spread into hedge bottoms by spinning disc or oscillating spout spreaders. No significant effects on percentage cover or total reprod uctive output by native populations of Bromus sterilis were apparent a fter 3 years although fertiliser caused a change towards the productio n of fewer, but larger panicles. Dry weight production and reproductiv e output of phytometers (B. sterilis plants transplanted into the hedg erows as seedlings) was positively correlated with levels of applied f ertiliser. These differences in response between transplanted seedling s and native populations were attributed to disturbance during the tra nsplantation procedure. It is suggested that short term misapplication of fertiliser to hedgerows may only have great effects on the 'weedin ess' of boundary vegetation when combined with mechanical or other dis turbance (e.g. herbicides).