Should we define volumic soil concentrations in mol of component per m3 or in mol of C per m3 and then use the CN ratio for N balance?

[GeraultTr]

@frees86
Along with DOM massic concentrations, should we define volumic soil concentrations in mol of labile organic components (hexose, amino-acids, mucilage and cells) per m3 or in mol of C per m3 and then use the CN ratio for N balance?

In both case we will need another parameter for each component, the average number of C per atom, because we will anyway need component concentrations for gradients with root, and C concentrations to aggregate all soluble components in the DOC and DON pools.

[frees86]

The C:N ratio of DOM is not expected to be fixed, so you could not really use it. The DOC and DON should be rather considered as independent from each other, then you express them in mol of C per m3 and mol of N per m3, respectively. You can assume that DOC and DON follow the same fate when leaching from one voxel to another. Only the story of microbial uptake of DON is a bit uncertain: should it depend on microbial use of DOC or not? That's why we need further testing...

[GeraultTr]

For the link between DON uptake and DOC degradation, I assume we need to investigate either this is an active transport or not from the litterature?

But still I don't understand how we can go from hexose, mucilage, released cells and amino acid mol.m-3 to DOC mol of C / m3. For molecules with a mix of C & N, we need to introduce a stoechiometry paremeter to be able to sum the individual rhizodeposits' contribution to overall DOC?

Also, if we consider DOC movements, we will still need to somehow split the incoming DOC flow for each type of rhizodeposits according a proportion to update individual concentrations, which seems weird to me. I would rather compute solute-specific transport and balance, then sum as DOC so it will impact the degradation rates on the next step. What do you think?

(All my questions would be the same for DON but I simplified here)