SEEDLING EMERGENCE OF ARTEMISIA-FRIGIDA IN RELATION TO HYDRATION DEHYDRATION CYCLES AND SEEDBED CHARACTERISTICS

Seedlings of Artemisia frigida emerged only when soil moisture was above -1.5 MPa and total emergence increased with the total amount of water supplied. Regardless of the watering regime, A. frigida required a minimum of 8-10 days before emerging at 10 degrees C and approximately 60 mm cumulative moisture to reach stable maximum emergence. When precipitation is low more seedlings will emerge if it is concentrated in a few events, while when precipitation increases, emergence will be greater if the intervals between precipitation events are short. A bare soil surface was the most favored seedbed and Selaginella densa inhibited emergence of A. frigida. However, even though few seedlings emerged from S. densa, this seedbed type is ecologically important because of its large coverage in the field.