FOREST SOIL MICROBIAL RESPONSE TO EMISSIONS FROM AN IRON AND STEEL WORKS

The influence of the emissions from an iron and steel works on soil respiration, fungal hyphal length, green-needle litter decomposition and microbial biomass C and N, in the humus of a Pinus sylvestris (L.) forest were investigated. Twelve study sites were established in a polluted area, 0.3-0.7 km from the plant. The same number of study sites were established in a control area, 3.5-4 km from the plant. The industrial emissions were manifested in significantly higher amounts of soil extractable cations (Ca, Mg, Mn, Fe, Zn, Al), higher soil pH and moisture, and lower total N and loss-on-ignition (LOI). A principal component analysis of the chemical data extracted a pollution axis which significantly explained the increase in fungal hyphal length and soil respiration in the polluted study sites and the opposite reaction for microbial biomass C and N. The percentage mass loss of green needle litter was not affected by the emissions from the steel works. The results are discussed in relation to forest soil liming.