Effects of ash fertilization and prescribed burning on macronutrient, heavy metal, sulphur and 137Cs concentrations in lingonberries (Vaccinium vitis-idaea)

The effects of ash fertilization and prescribed burning on the P, K, Ca, Mg, Mn, S, Fe, Al, Cu, Zn, Cd, Cr, Ni and Cs-137 concentrations in lingonberry (Vaccinium vitis-idaea L.) berries were investigated in a 100-year-old Scots pine (Pinus sylvestris L.) stand growing on a dry site in central Finland. The treatments were control, prescribed burning and three ash-fertilizer doses of 1000, 2500 and 5000 kg ha(-1). The size of the plots was 30 x 30 m, and there were four replications per treatment. Lingonberries were collected two (1991) and seven (1996) growing seasons after the treatments. Ash fertilization had no effect on the heavy metal concentrations in the berries. Potassium was the only macronutrient whose concentration in the berries significantly increased after ash fertilization (5000 kg ha(-1)). Prescribed burning increased the berry Cd concentrations, which, however, remained low even after prescribed burning, The berry Cs-137 concentrations decreased as a result of ash fertilization and prescribed burning. The reduction in Cs-137 concentrations caused by ash fertilization may be an important finding especially for areas where the picking and consumption of berries has to be restricted as a result of radioactive fallout. (C) 2000 Elsevier Science B.V. All rights reserved.