The influence of rock powders on microbial activity of three forest soils

Abstract

Abstract To improve the quality of forest soils by applying basic rock powders tests were carried out in Vorarlberg (Austria) in 1987: in the vicinity of Möggers on Stagno‐Mollic Gleysol under Abieti‐Fagetum luzuletosum , in Nenzing on Calcaric Regosol and Cambisol under Abieti‐Fagetum luzuletosum and in Montafon on Stagno‐Dystric Gleysol under Homogyno‐Piceetum . The effects of a low dosage of rock powder application on nitrification, basal respiration, microbial biomass, xylanase, phosphatase and protease activities, the amount of nitrate nitrogen (NO 3 − ‐N), and the soil pH were investigated. Additions of rock powder increased protease, NO 3 − ‐N content and pH, but decreased phosphatase in the A h ‐horizon of the Stagno‐Mollic Gleysol. After 3 years the A h ‐horizon from the experimental site Nenzing showed statistically verified differences of all investigated parameters except xylanase. In the acid spruce forest soils of the Montafon site the rock powder had no statistically significant effect on microbiological parameters. Only the soil pH increased. It can be postulated that the application of rock powders furthered C‐ and N‐mineralization. In the long run this affects the turnover of mineral nutrients in forest ecosystems.