Table 1.

Model variables and parameters. Units correspond to values that would be expected in an agricultural field trial.

Variable	Description	Unit
dCday	Daily gross productivity	tDW ha–1
dCday	Daily root P uptake	kgP ha–1
Ci	Current C pool	tDW ha–1
Pi	Current P pool	kgP ha–1
$C_i^{*}$	Updated C pool	tDW ha–1
$P_i^{*}$	Updated P pool	kgP ha–1
dCi	Daily C allocation	tDW ha–1
rCi	Daily C respiration	tDW ha–1
dPi	Daily P allocation	kgP ha–1
mPi	Daily grain remobilised P	kgP ha–1
Constant
dt	Time step	day
kCL	Assimilation rate	tDW tDW–1 leaf day–1
kPR	Root P uptake rate	kgP tDW–1 root day–1
CL,max	LUE half-saturation point	tDW leaf ha–1
ρL,max	PUE half-saturation point	kgP tDW–1 leaf
fC,i=S,G	C allocation fraction	tDW tDW–1 leaf
λC,i=L,R, S,G	C respiration rate	day–1
fP,i=R,S	P allocation fraction	kgP kgP–1leaf
kmP , i =R, L, S	Grain P remobilisation fraction	tDW–1 grain day–1

For the hydroponic studies, the units change according to the scale of the experiment to gDW pot ^–1 for biomass and mgP pot ^–1 for P. i denotes organs which are leaves (L), roots (R), stem (S), and grain (G). DW stands for dry weight.