Effects of liming and fertilization on growth, soil chemistry and soil water chemistry in a Norway spruce plantation on a nutrient-poor soil in Denmark

Abstract

During recent years indications of nutritional imbalances in coniferous forest ecosystems have become more common in southern Scandinavia and central Europe. Deposition of acidifying substances, and relative deficiencies of nutrients, and soil acidification are supposed to be important contributing factors in the picture of forest damage. The need for counteractions such as liming and fertilization is thus pressing. A combined liming and fertilization trial was performed in a 59-year-old Norway spruce stand on a nutrient-poor soil at Klosterhede, Denmark. Two types of lime (calcite and dolomite combined with additional kieserite and phosphorus) were applied alone and in combination with conventional NPK fertilizer to form five different treatments. The treatments were carried out in 1986 and in 1994. All the treatments led to significantly increased leaching of ions from the soil within the first 8 months after treatment. Combined calcite and kieserite applications induced acidification pushes in the first period after the treatments. The magnitude of these changes varied strongly according to the different treatments. The alteration of the chemical composition of the soil water seemed to peak within 8 months following the treatments and it was largely eradicated 8 years after establishment of the trial, and 3 years following the last NPK fertilization. The desired geochemical changes of the soil solid phase regarding the counteraction of acidification were achieved in the upper horizons of limed plots (decreased exchangeable acidity (AC) and concentration of exchangeable Al 3+, and increased concentration of exchangeable Ca 2+ and Mg 2+, base saturation (BS), cation exchange capacity (CEC) and pH H 2O ). Results from the O horizons (N and C concentration, C N ratio and horizon thickness) indicate that mobilization of nitrogen did not increase notably within the first 8 years of treatment in the limed plots, even though the pH H 2O in the O horizon of the limed plots was increased and the C N ratio was below 30. The various treatments caused no significant differences in growth increment. The strongest effect observed was a growth rate reduction caused by application of kieserite and calcite. This reduction can presumably be ascribed to stress or even toxicity caused by the increased concentrations of Al 3+ and SO 4 2−, and decreased levels of pH in the soil water in the first period after the treatment.