Cj. Westman et S. Jauhiainen, SOIL ACIDITY IN 1970 AND 1989 IN A CONIFEROUS FOREST IN SOUTHWEST FINLAND, Canadian Journal of Soil Science, 78(3), 1998, pp. 477-479
Forest soil pH in southwest Finland was measured with identical sampli
ng and analysing methods in 1970 and 1989. The acidity of the organic
humus layer increased significantly as pH values measured on water and
on salt suspensions decreased between the two sampling dates. For the
mineral soil layers, no unambiguous trend was found, pH values measur
ed on salt suspension tended to be unchanged or lower, while pH on wat
er suspension in some soil layers were even higher in 1989 than in 197
0.