growth modifier for nitrogen availability

nitrogen response

Plant-available nitrogen (Nav) is used in response functions following Pastor and Post (1985) to derive the soil nutrient modifier fN (cf. Landsberg and Warings' (1997) fertility rating). We re-calculate the three N response classes of Pastor and Post (1985) as (Eq. 1)

\[\begin{aligned} f_{N}=max(1-e^{a_{N}\cdot (N_{av}-b_{N})}\: ;\: 0) \end{aligned} \] Eq. 1

with aN (-0.045, -0.055, -0.065) and bN (10, 25, 40) empirical parameters and the respective values for the three classes (tolerant, intermediate, intolerant of low N availability). This approach to derive growth response to N has been successfully applied in a number of gap model models, including LINKAGES (Wullschleger et al. 2003), ForClim (Bugmann 1996) and (in modified form) PICUS (Seidl et al. 2005).


Seidl, R., Rammer, W., Scheller, R.M., Spies, T.A. 2012. An individual-based process model to simulate landscape-scale forest ecosystem dynamics. Ecol. Model. 231, 87-100.

Created by rupert. Last Modification: Wednesday 09 of October, 2013 10:29:42 CEST by mariana.