PERFORMANCE OF HIGHBUSH BLUEBERRIES ON SITES PREVIOUSLY USED FOR AGRICULTURAL CROPS

Highbush blueberries (Vaccinium corymbosum) planted on arable land (previously cultivated with agricultural crops) showed very poor development, whereas plants on virgin land (cleared forest land) had good vegetative and generative growth. The differences in plant development at previously differently used sites can not sufficiently be explained by changes in physical or chemical soil properties or by various nutrient supply due to former land use (Bläsing, 1986).

A field study was conducted with Vaccinium corymbosum on a forest site (spontaneous seedlings in a pine forest), virgin land and arable land (both with cultivated plants). Root distribution measurements showed that plants on the forest site had widely spread, not very dense root systems, while the root systems on arable land were very dense and restricted to a small soil volume. Plants on virgin land had intermediate root growth. The Vaccinium roots at all sites were infected with ericoid mycorrhiza. The infection status was highest on the forest site and lowest on arable land, where a high assessment with non- mycorrhizal fungi was observed.