The effect of nitrogen fertiliser on the growth of Bromus sterilis in field boundary vegetation

Abstract Results from the first 3 years of experiments investigating the effects of mis-application of nitrogen fertiliser to hedgebank vegetation are 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 reproductive output by native populations of Bromus sterilis were apparent after 3 years although fertiliser caused a change towards the production of fewer, but larger panicles. Dry weight production and reproductive output of phytometers ( B. sterilis plants transplanted into the hedgerows as seedlings) was positively correlated with levels of applied fertiliser. These differences in response between transplanted seedlings and native populations were attributed to disturbance during the transplantation procedure. It is suggested that short term mis-application of fertiliser to hedgerows may only have great effects on the ‘weediness’ of boundary vegetation when combined with mechanical or other disturbance (e.g. herbicides).