Effect of Pruning and Urea Fertilization on Rejuvenation of Cultivated Lingonberry ( Vaccinium vitis-idaea L.) with Special Reference to Mycorrhizal Infection

Lingonberry (Vaccinium vitis-idaea L.) growth and development was studied in field experiments in Viikki, Finland (60°10′N, 25°00′E). The effects of pruning height (1 and 5 cm above ground) and urea fertilization (0-10 g m−2) were examined for their capacity to rejuvenate 10 year old lingonberry vegetation. Lingonberry roots collected from an experimental field were compared with those from wild stands for the presence of mycorrhizas. Lingonberry vegetation recovered exceptionally well from pruning after one growing season. High pruning (5 cm) resulted in higher number of new shoots than low pruning (1 cm), but low pruning and 5 g urea produced the most generative shoots and the greatest number of flower buds. Fertilizer application, in general, had very little effect. Fungal hyphae were detected in the root epidermis. Advantages of low pruning in lingonberry management and the effect of ammonium and nitrate nitrogen and role of mycorrhizal infection in nutrient uptake of lingonberry are discussed.