Growth reductions in cocksfoot (Dactylis glomerata L.) as a result of SO2 pollution

The effects of exposing Dactylis glomerata L. to 11 pphm SO₂ for four weeks were investigated using a wind tunnel fumigation system. The pollutant was found to cause significant reductions in the numbers of tillers and green leaves, leaf area, root/shoot ratio and all dry weight fractions measured. The percentage yield reductions found for D. glomerata were compared with those previously found for Lolium perenne L. under the same conditions of exposure. It was concluded that D. glomerata may be slightly more sensitive to SO₂ than L. perenne. The magnitudes of the yield reductions found in these experiments are greater than those previously reported and this is discussed in relation to the rate of air movement through the fumigation system. It is concluded that the effects of SO₂ on plants in the field, and subsequent losses in the yields of crops, may have been under-rated in the past.