Influence of salt content of pliocene clay soil on the emergence of six grasses

The effects of three soil salinity levels (450, 925, and 1150 μS/cm) on the emergence of six grasses from a clay badland area of central western Italy were investigated. The species were five annuals (Aegilops geniculata, Brachypodium distachyum. Hordeum maritimum, Parapholis incurva, and Parapholis strigosa) growing in the pioneer association ParapholidoArtemisietum creataceae and the perennial Bromus erectus, the dominant species of perennial grasslands. The tests were made in plastic pots filled with soils having different salt contents. A control, conducted in Petri dishes with distilled water, showed a high germination percentage for all species but different germination rates. In the soil tests, the emergence rate of all the species decreased with increasing soil salinity. Final emergence percentages were higher than 70% for all species and all salinities, except for P. incurva and P. strigosa (60 and 46.7%, respectively) at the highest salinity level. B. erectus showed the lowest emergence rate at all salinities, in line with its ecological features.