View article

Sphagnum‐bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear whether P‐addition can alleviate physiological N‐stress in Sphagnum plants. A 3‐year fertilisation experiment was conducted in lawns of a pristine Sphagnum magellanicum bog in Patagonia, where competing vascular plants were practically absent. Background wet deposition of nitrogen was low (∼0.1–0.2 g·N·m⁻²·year⁻¹). Nitrogen (4 g·N·m⁻²·year⁻¹) and phosphorus (1 g·P·m⁻²·year⁻¹) were applied, separately and in combination, six times during the growing season. P‐addition substantially increased biomass production of Sphagnum. Nitrogen and phosphorus changed the morphology of Sphagnum …