Spatial Variation in Soil pH of Beech Forests in Relation to Buffering Properties and Soil Depths

Abstract

The relations between variation in soil pH at distances ranging from 0.05 m to 4 m were examined on three data sets concerning beech forests on Brown Forest Soils by using a requisite sampling design and cumulative frequency distributions of difference in soil pH. Scales of spatial variation were found to exist, i.e. variation increased with an increase in distance between sampling points. Two critical distance ranges were distinguished where variation plateaus with no increase seemed to exist, viz 0.10.7 m and 1.5-2.5 m, the former coinciding with the annual growth length (reported in the literature) of two important field layer species (Mercurialis perennis L. and Lamium galeobdolon L.). Parts of the pH range with rapid pH buffering were found to be related to low spatial variation in soil pH and vice versa. Spatial variation was shown to be independent of soil depth within 1 m horizontal distance, but for distances greater than 1 m the deeper soil layers (16-35 cm soil depth) displayed a higher variation than the uppermost ones (0-9 cm soil depth), possible causes being large-scale patterns in water flow and root growth.