The importance of rock-derived mineral nutrients (P, K, Mn, Mg, and Ca) in plant physiological function is well established. However, one important and relatively unexplored question is whether or not the same rules of plant nutrient use efficiency apply to these essential elements even if they are not limiting to primary production. We examined conifer growth and nutrient use dynamics across sites with contrasting geologies (sedimentary and volcanic) that vary in both rock-derived mineral nutrient and N availability. Differences in bedrock geochemistry generally corresponded to differences in available soil nutrients, such that the volcanic site tended to have greater available nutrients. Foliar nutrient concentrations reflected both differences in bedrock chemistry and indices of available soil nutrients for P, K, and Mn. Aboveground biomass production did not follow expected patterns and was greater for trees growing on low nutrient sites, but only with respect to the annual woody increment. Fine litter production did not differ between sites. Finally, we found evidence for trade-offs between two commonly examined components of nutrient use efficiency (NUE): nutrient productivity (A n) and mean residence time of nutrients. However, we did not find evidence for higher plant NUE in soils with lower nutrient availability for N or rock-derived nutrients.
Bibliographical noteFunding Information:
Acknowledgments We are grateful for the assistance with laboratory and fieldwork provided by C. Lawrence, D. Fernandez, J. Carr-asco, C. Flagg, and Z. Seligman. We would like to thank W. Bowman, N. Barger, T. Zelikova, M. Keville, and B. Sullivan for their comments and advice on an early version of this manuscript. This work was support by an A. W. Mellon Foundation grant made to J. C. Neff.
- Mineral nutrition