Residue management

TOC

Description

Residues, i.e. above ground biomass from crops that are not the organ for which the crop is cultivated for (e.g. straw) can be harvested for specific purposes (e.g. feed) or left on the field to decay. In practice, residues can also be burnt in the field.

Details

This is implemented only for the carbon balance of cultivated soils.
Burning of residues is also implemented to diverge some carbon to the fire flux, but for soil carbon it’s equivalent to residue removal in LPJmL4 (carbon only version).
In LPJmL5, with nitrogen, that looks different, of course.

Technical Note

Residues in or out can so far only be specified at the global level. There’s a flag in
lpjml.conf|js that specifies whether residues are in or out.
Several things are still hard-coded (and in principle could be moved to param.par as well)
Whether to burn residues is specified here
lpjml.conf|js and the fraction to remove is set to 90% by default, see parameter in par/param.par and the computation in src/crop/harvest_crop.c

If residues are removed, the output file pft_rharvest is filled with values.

See Also

harvest, Output, carbon pools, Crop functional types

References

Bondeau A, Smith P C, Zaehle S, Schaphoff S, Lucht W, Cramer W, Gerten D, Lotze-Campen H, Müller C, Reichstein M and Smith B 2007 Modelling the role of agriculture for the 20th century global terrestrial carbon balance Global Change Biology 13 679-706 http://dx.doi.org/10.1111/j.1365-2486.2006.01305.x