Liming and wood ash application are measures to decrease acidification
of forests soils. The assessment of lime requirement can be based on
that base saturation which indicates a low risk of acid toxicity. Beca
use of a wide spread Mg deficiency in Central European forests, Mg con
taining lime is normally applied. Ash from untreated wood is applied t
o decrease soil acidity as well as to improve K and P nutrition. In wo
od ash, K is the most soluble nutrient, follwed by Ca and Mg. The over
all dissolution rate of lime applied to the forest floor is about It h
a(-1) a(-1). After liming, soil solution alkalinity and Mg concentrati
ons increase markedly, while changes of Ca, H ions and Al concentratio
ns are less pronounced. After the application of wood ash, K concentra
tions increase due to the high K content and the high solubility of K
in wood ash, After the application of a sufficiently high dosage of li
me to the forest floor, the decrease of acidity in deeper soil layers
may need decades because of the low solubility of lime. Nitrification
and nitrate leaching induced by lime or wood ash may reduce their acid
buffering efficiency.