Biomass partitioning

Daily aboveground biomass (AGBd, kg m-2 d-1) (see Crop growth) is partitioned to leaves, panicles and stems.

AGBd is partitioned to leaves using a parabolic function which assumes the maximum value (input parameter; RipL0) at emergence and zero at flowering:

where DVS is development stage code (see Crop development), LeavesAGBd (kg m-2 day-1) is the AGBd partitioned to leaves. This approach to partitioning (based on a single parameter, RipL0) is a compromise between the SUCROS approach (van Keulen et al., 1982), considered difficult to be reasonably parameterized for large scale simulations and other simple, empirical approaches (e.g. the CropSyst approach, Stöckle et al., 2003).

AGBd partitioning to panicles starts at the panicle initiation stage (PI) and it is assumed as maximum (all the accumulated biomass is partitioned to panicles) at the beginning of the ripening phase. Like for the allocation of AGBd to leaves, a parabolic function is used:

where PanicleAGBd (kg m-2 day-1) is the AGBd partitioned to panicles.

In case the option for the simulation of spikelet sterility is activated, PanicleAGBd is daily multiplied by [1-sterility factor], with sterility factor (unitless) assuming values from 0.0 (0% sterility) to 1.0 (100% sterility).

Stem biomass is derived by subtracting panicles and leaves biomasses to total above ground biomass.

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