Passive plant uptake

A passive plant uptake of trace elements can optionally be chosen in the model (see switch PassiveUptake). This uptake is calculated for the leaf, stem and roots separately, and is a function of plant water uptake, W_upt (see section Water uptake by roots). Thus, passive trace element uptake from the mineral pool to the leaf, S_{TEMin→TELeafP}, is calculated as:

                                         (2.62)

where C_TEMin is the concentration of trace elements in the dissolved phase, s_PUscale is a scaling parameter determining the efficiency of the uptake, and f_PULeaf is an fraction of the total passive uptake allocated to the leaf.

The same equation is used analogously to calculate the passive uptake to stem, S_{TEMin→TEStemP}, and roots, S_{TEMin→TERootsP}, by exchanging f_PULeaf to f_PUStem or f_PURoot respectively. The root fraction, f_PURoot, is calculated by:

                                                                   (2.63)

The total passive uptake of trace elements, S_{TEMin→TEPlantP}, is the sum of the passive uptake to the leaves, stem and roots.