REGULAR ARTICLE Soil fungi appear to have a retarding rather than a stimulating role on soil apatite weathering Mark M. Smits & Leif Johansson & Håkan Wallander Received: 7 April 2014 /Accepted: 25 July 2014 # Springer International Publishing Switzerland 2014 Abstract Aims Vegetation stimulates, in general, soil mineral weathering. It has been hypothesized that plant- associated microorganisms, especially ectomycorrhizal fungi play a major role in this process. We studied apatite dissolution in a vegetation gradient in southern Norway to test the role of ectomycorrhizal vegetation on mineral weathering. Methods A natural occurring lead contamination, prob- ably present since the last glaciation, caused a gradient from bare soil, via sparse grass to healthy spruce forest. We measured apatite content, soil solution chemistry, δ 13 C, δ 15 N, C, N and ergosterol content in soil profiles along the gradient. Results The apatite loss for each soil depth could be described by the same proton-based, dissolution function over the whole vegetation gradient. The devi- ation from the 30–40 cm depth pH model showed, in the top 20 cm, a negative correlation with ergosterol, and a positive correlation with δ 13 C. These correlations could reflect an inhibiting effect of biotic activity through the production of large weight organic acids and degrada- tion of low molecular weight organic acids. Conclusions Vegetation accelerates apatite dissolution by acidifying the soil solution, but soil fungi appeared to have a retarding, rather than an enhancing effect on this process. Keywords Apatite . Fungi . Vegetation . Weathering . DOM Introduction Rock-forming minerals are the primary source of most plant nutrients (Marschner 1995 ). But mineral weathering is a slow process. In most soils nutrient input from mineral weathering into the available nutrient pool is small compared to recycling of organically bound nutrients (Schlesinger 1991), but essential to compen- sate for nutrient losses from the ecosystem. In this light it is important to know the drivers of mineral weathering in soils. Several field studies have demonstrated the stimulating effect of vegetation, and forests in particular, on mineral dissolution rates (Moulton et al. 2000; Nezat et al. 2004; Taylor et al. 2009). As most plants live in symbiotic relationship with mycorrhizal fungi (Smith and Read 2008), associated with their roots, these fungi Plant Soil DOI 10.1007/s11104-014-2222-6 Responsible Editor: Thom W. Kuyper.. Electronic supplementary material The online version of this article (doi:10.1007/s11104-014-2222-6) contains supplementary material, which is available to authorized users. M. M. Smits (*) Centre for Environmental Sciences, Environmental Biology Group, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium e-mail: mark.smits@uhasselt.be M. M. Smits : H. Wallander Department of Microbial Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden L. Johansson Department of Geology, Lund University, Sölvegatan 12, 223 62 Lund, Sweden