Effect of grit grade and grit source on the germination, early morphology and health of Sitka spruce (Picea sitchensis (Bong.) Carr.).

Abstract

The impact of grit grade and source on the seed germination, early morphology and health of Sitka spruce (Picea sitchensis (Bong.) Carr.) germinants and on soil pH was investigated in a greenhouse trial. Seed germination, germinant morphology and health were best in the coarse (2.0-6.0 mm) grits, and grit source had no effect. Germination percentage, germinant size and number of healthy germinants were lowest in the fine (0.2-2.0 mm) grits, and there was significant variation among grit sources. The pH of the soil was increased in three grit sources within this grade, and in one by nearly two pH units. Results for the mixed (0.2-6.0 mm) grits were closer to those obtained for the coarse grits for all variables except soil pH, but grit source effects were significant. The pH values for this grade were almost identical to those obtained for the fine grits.