ROOT DYNAMICS IN A SALT-MARSH OVER 3 CONSECUTIVE YEARS

The minirhizotron technique has been used to study root development in a salt marsh in the western part of the ''Nationalpark Niedersachsisc hes Wattenmeer'' during a three-year period. The objective of our stud y was to evaluate root depth distribution and seasonal changes in grow th activities of natural plant root systems. Root number was counted a t monthly intervals in the top soil layer (0-0.2 m) for every 2 cm soi l depth. The number of roots was regarded as an easily detectable para meter reflecting root growth and decay. In general, highest rooting in tensity was found in the soil's subsurface layer (0-0.08 m). The numbe r of roots significantly decreased in deeper horizons of the soil. The re was also a significant increase and decrease in the number of roots in the course of a year. The highest rooting intensity was found in l ate winter to early spring, which substantially decreased towards mid summer when the plants were in their reproductive phase. The data indi cate that there is a clear seasonal pattern of root growth of salt mar sh species.