Above-ground phytomass and below-ground biomass prodution of Salvia verbenaca Linné

Abstract

Salvia verbenaca L. is a ruderal herbaceous plant, very common in the Mediterranean region. Its flowers are prized for their appearance, and it displays a high degree of adaptability in relatiopn to habitat sites with a paucity of resources. The objective of this study was to obtain data about the prodution of phytomass and root biomass, with a view to the probable use of this species in urban green spaces. A two-year field experiment was undertaken, comprising four tratments of eight randomly selected plots, four being used in each year. This species was manual seed broadcast at the following densities: 20 000, 15 000, 10 000,5 000 viable seeds m2. The prodution of phytomass and root biomass was assessed through periodic collections, during the seasonal cycle of the species under study. In the first year there appears to have been a tendency for an increase in seed density to cause an increase in phytomass production. In the second year, by which time the plants had settled, when seed density rose from 5 000 to 10 000, a slight increase in phytomass prodution occurred. However, when the seed density rose from 10 000 to 20 000 seed m2 a decrease in phytomass production was observed. Root biomass in the first year, had minimum value in January and a maximum value in june-July. In the second year, the highest values were observed in May. The relationship between above and below ground biomass, for the first-year experiment, decreased over the cutting dates. However, an inverse behaviour occurred in the second year. Although the values of the phytomass obtained did not reveal statistically significant differences between treatments, when the plants were found already established, they appeared to indicate that densities of seeding between 5 000 and 10 000 m2 could be more advantageous.