BORON RETENTION IN LIMED FOREST MOR

Boron (B) retention was studied in the mor humus of podzolic soil from boreal Norway spruce (Picea abies (L.) Karst.) forests. In a long-ter m liming experiment, ground limestone had been applied 30 years earlie r and again 12 years before sampling. Additionally a short-term field experiment was done to separate the effect of increased pH from calciu m (Ca) addition. In the short-term experiment the treatments were cont rol and two doses of CaCO3, CaSO4 and sodium + potassium (Na + K) carb onate mixture. These treatments were applied in the year before sampli ng. The B retention data conformed to a Freundlich model better than t o a Langmuir model. Considerable B adsorption occurred, probably mostl y due to the large organic matter content of mor. Liming significantly increased the quantity of adsorbed B in both experiments. Incubation with added B for 8 weeks considerably increased B retention and reduce d the difference between limed and unlimed soil. CaSO4 had no effect o n B retention characteristics, whereas Na + K treatment caused changes similar to those of lime. Therefore Ca probably has little influence on B adsorption in this pH range (3.0-5.9).