Wood Ash Application and Liming: Effects on Soil Chemical Properties and Growth of Scots Pine Transplants

摘要

The effects of varying doses of wood ash (2.5 and 5.0 t ha~(-1)) and limestone (1.0, 2.0 and 4.0 t ha~(-1)) on soil chemical properties and growth of Scots pine (Pinus sylvestris L.) transplants on an acidic forest soil were investigated in a reforestation area in eastern Finland. The ash and limestone were applied either on the soil surface or were mixed into the topsoil using disc ploughing. All the treatments were replicated three times. Soil samples were taken from the unploughed plots only. Woodash and liming had reduced acidity in both the organic layer and 0-10 cm mineral soil layer for 15 years after application. The pH increase in the organic layer was 1.6 and 2.7 pH units on the plots treated with 2.5 and 5 t ha~(-1)of ash, and 0.7, 1.0 and 1.7 units on the plots treated with 1, 2 and 4 t ha~(-1) of lime, respectively. Depending on the dose, ash application resulted in a significant 41 to 47% increase and liming 34 to 46% increase in the base saturation of the organic layer. Surface broadcast of ash and lime significantly increased height growth. On the ash plots the mean height after 15 years was 24-27% and on the limed plots 14-23% greater than on the control plots. There were also signs of an increase in breast height diameter causedby ash application and liming. Liming or ash application after being mixed into the surface soil by ploughing had no effect on height growth of the pines, except for the highest lime dose. Instead, ploughing as such had a significant increasing effect both on survival and height growth of the trees.