THE EFFECTS OF SALT WATER AND SOIL TYPE UPON THE GERMINATION, ESTABLISHMENT AND VEGETATIVE GROWTH OF HOLCUS LANATUS L. AND LOLIUM PERENNE L.

Abstract

SUMMARY Holcus lanatus is the dominant grass over large areas of thin peat soil on the western sea‐cliffs of Lundy Island, exposed to salt spray. Its tolerance of artificial sea water (ASW) on peat or loam soils when grown alone or in mixture with either an agricultural cultivar of H. lanatus, Massey Basyn or with ‘Aberystwyth S. 23’Lolium perenne was investigated. Under salt spray, on peat soil, ‘Lundy’H. lanatus had the highest tillering ability and, unlike the others, its yield was unaffected by the spray. When high levels of salt were applied to the soil, the yield of L. perenne was lowest when it was grown on peat and was also in competition with ‘Lundy’H. lanatus. On peat soil, the agricultural cultivar of H. lanatus was more productive than L. perenne. It was also at least as productive as ‘Lundy’H. lanatus when grown on peat with a high level of salt in the soil solution.When immersed in a solution of ASW, the leaves of L. perenne retained approximately 17 times more salt than did those of either ‘Lundy’ or ‘Massey’H. lanatus. There was no evidence for sodium ions being adsorbed on to the cuticle of any of the grasses. ‘Seeds’ of both L. perenne and ‘Massey’H. lanatus germinated readily in 40% ASW. However, germination of ‘Lundy’H. lanatus‘seeds’ was much reduced at this salt level, especially from intact spikelets, although they germinated readily when transferred to fresh water. The establishment of ‘Lundy’H. lanatus under 120 kg ha−1 day−1 of sea‐salt was slower than that of the other two grasses.