How do root production and mortality affect soil carbon storage and nitrogen cycling?
Scaling plant nutrient use in nutrient-limited peatland ecosystems. A major finding of my research in peatlands was that the efficiency with which plants used nutrients differed at scales ranging from the leaf- to community level, and depended on whether the individual, species, and community were limited more by nitrogen or phosphorus availability. Nutritional constraints control excess carbon storage under elevated atmospheric [CO2]. In general, forests do not use nitrogen more efficiently for biomass production under elevated [CO2], due in large part to the way that carbon is allocated within the stand. For example, the increased production of ephemeral fine roots in a CO2-enriched sweetgum plantation necessitated increased nitrogen uptake from the soil to produce roots with a high nitrogen concentration. A nitrogen fertilization experiment in an adjacent sweetgum stand indicated that the increased production of ephemeral roots was most likely a mechanism for greater nitrogen acquis
