Table 1.

List of symbols of parameters of the source–sink model, and their definitions and units

Symbol	Definition	Unit
t	Days after anthesis	d
t b	Anthesis date (denoted as days after anthesis, so, set as zero in the model)	d
t m.si	Days after anthesis when the daily sink strength is maximal	d
t e.si	Days after anthesis when the daily sink strength has decreased to zero. te.si.M and te.si.N represent te.si for biomass and nitrogen, respectively	d
W si	Observed grain dry mass or nitrogen mass per unit ground area	g m–2
W b.si	Initial grain dry mass or nitrogen mass at anthesis (set as zero in the model)	g m–2
W x.si	Maximum grain dry mass or nitrogen mass per unit of ground area	g m–2
s max.si	Maximum sink strength (i.e. maximum rate of grain filling)	g m–2 d–1
$\overline{s}$ si	Mean sink strength (i.e. mean grain-filling rate) of the whole grain-filling period. $\overline{s}$si.M and $\overline{s}$si.N represent $\overline{s}$si for biomass and nitrogen, respectively	g m–2 d–1
S tot.si	Total sink demand of the whole grain-filling period. Stot.si.M and Stot.si.N represent Stot.si for biomass and nitrogen, respectively	g m–2
t m.so	Days after anthesis when the daily source activity declines at a maximum rate	d
t e.so	Days after anthesis when the daily source activity has decreased to zero. te.so.M and te.so.N represent te.so for biomass and nitrogen, respectively	d
W so	Observed above-ground biomass or nitrogen mass per unit ground area	g m–2
W b.so	Above-ground biomass or nitrogen mass per unit ground area at anthesis	g m–2
W x.so	Maximum above-ground biomass or nitrogen mass per unit ground area at the end of grain filling	g m–2
s max.so	Maximum daily source activity, which is set to be achieved at the onset of grain filling	g m–2 d–1
$\overline{s}$ so	Mean source activity of the whole grain-filling period. $\overline{s}$so.M and $\overline{s}$so.N represent $\overline{s}$so for biomass and nitrogen, respectively	g m–2 d–1
S tot.so	Total source supply of the whole grain-filling period. Stot.so.M and Stot.so.N represent Stot.so for biomass and nitrogen, respectively	g m–2
RE	Contribution of remobilized pre-anthesis biomass (or nitrogen) needed to final grain dry biomass (or final grain nitrogen mass)	%