Sulfur dynamics during long-term ecosystem development

Long-term soil and ecosystem development involves predictable changes in nitrogen (N) and phosphorus (P) availability and limitation, but far less is known about comparable changes in sulfur (S) despite its importance as an essential plant macronutrient and component of soil organic matter. We used a combination of elemental analysis, X-ray absorption spectroscopy, hydrolytic enzyme assays, and stable S isotope ratios to examine S in soil and leaf tissue along the 120,000-year Franz Josef chronosequence, New Zealand. Total soil S concentrations increased during the early stages of pedogenesis and then declined as soils aged. There was little variation in soil N:S ratios along the chronosequence other than in the youngest (5 year old) soil, although the carbon (C):S ratio increased markedly in the oldest soils and the P:S ratio decreased continuously along the chronosequence. Foliar S concentrations and N:S ratios varied widely among common plant species but did not change consistently with increasing soil age, although foliar P:S declined for several species in the older stages of the chronosequence. The chemical nature of soil organic S extracted frommineral and organic horizons and determined by S K-edge X-ray absorption nearedge fine-structure (XANES) spectroscopy was dominated by C-bonded S distributed approximately equally in highly-reduced and intermediate oxidation states, although ester-bonded S was also abundant throughout the chronosequence. Soil sulfatase activity expressed on a soil C basis was highest in young soils, indicating low S availability in the early stage of pedogenesis. Enzymatic C:S and N:S ratios varied little during ecosystem development, although the enzymatic P:S ratio increased continuously along the chronosequence. Stable S isotope ratios (dS) Responsible Editor: Steven Perakis. Electronic supplementary material The online version of this article (doi:10.1007/s10533-016-0208-6) contains supplementary material, which is available to authorized users. B. L. Turner (&) Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama e-mail: [email protected] L. M. Condron Agriculture and Life Sciences, Lincoln University, P.O. Box 84, Lincoln 7647, New Zealand C. A. M. France Museum Conservation Institute, Smithsonian Institution, 4210 Silver Hill Road, Suitland, MD 20746, USA J. Lehmann D. Solomon Department of Soil and Crop Sciences, Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY 14853, USA D. A. Peltzer S. J. Richardson Landcare Research, P.O. Box 69040, Canterbury, Lincoln 7640, New Zealand