This working group aims to integrate theory and evidence about competing nitrogen acquisition strategies, about phosphorus in the regolith, and about mycorrhizal strategy.

Arising from the first meeting, a review was developed (Adams, Rennenberg, Warren, Schmidt) about the proportions of different N-fractions (different amino-acids and other components) in plant tissues.

The second and third meetings pursued two main topics:

1. A review of the costs of taking up nitrogen from different N-sources, e.g. directly from organic matter via mycorrhizas, from dissolved organic N (amino-acids), from NH4 in soil solution, from NO3 in soil solution, via N-fixation from the atmosphere. P-relations are also under consideration. This review is associated with some theory and model building about the game-theoretical relations between alternative plant uptake strategies that focus on different N-sources.

2. Modifying Rastetter's multiple-element-limitation model MEL for the particular purpose of investigating competition among alternative N-uptake strategies. Since MEL is capable of simulating soil nutrient relations and plant nutrient strategies during extended successions leading to old and nutrient poor soils, this potentially connects the quantification of nutrient uptake costs to plant ecological strategies and to long-term ecosystem development and retrogression.

A short manuscript about different nitrogen uptake strategies is in review, and a more comprehensive review manuscript is being prepared. Discussions at this working group also led on to formation of WG26 Phosphorus in Landscapes.

Last updated March 2007