20.2 Soybean Plant Growth Model Equations
Assimilates(t) ¼ Assimilates(t À dt) + (photosynthesis À Allocation_to_stem À
Allocation_to_root À Allocation_to_seed À Allocation_to_Leaf_Area À
Shoot_Maintenance_Respiration - Root__Maintenance_Respiration) * dt
INIT Assimilates ¼ 0
INFLOWS:
photosynthesis ¼ leaf_area * ((Leaf_Assimilation_Rate * 3600) * 0.000012) * day_night__
switch- (photoinhibition * 3600) * 0.000012
OUTFLOWS:
Allocation_to_stem ¼ if time <¼ 1800 then Assimilates * percent_to_stem * root_
shoot__switch else 0
Allocation_to_root ¼ if time <¼ 500 then Assimilates * percent_to_root * root_
shoot__switch else Assimilates * 0.08 * root_shoot__switch
Allocation_to_seed ¼ (1-seed__Switch_control) * (1-seed__Switch_control_2)
* Assimilates * percent_to_seed
Allocation_to_Leaf_Area ¼ if time <¼ 2200 then Assimilates * percent_to_leaf
* leaf_switch else 0
Shoot_Maintenance_Respiration ¼ (Assimilates * Shoot_Maintenance_Rd)
Root__Maintenance_Respiration ¼ (Assimilates * Root_Maintenance_Rd)
Leaf(t) ¼ Leaf(t À dt) + (Allocation_to_Leaf_Area - Senescence) * dt
INIT Leaf ¼ 0.09
INFLOWS:
Allocation_to_Leaf_Area ¼ if time <¼ 2200 then Assimilates * percent_to_leaf
* leaf_switch else 0
OUTFLOWS:
Senescence ¼ if time <¼2200 then leaf * senesence_switch * 0.002 else leaf
* senesence_switch_2 * .02
Root(t) ¼ Root(t À dt) + (Allocation_to_root) * dt
INIT Root ¼ 0
INFLOWS:
Allocation_to_root ¼ if time <¼ 500 then Assimilates * percent_to_root * root_
shoot__switch else Assimilates * 0.08 * root_shoot__switch
Seed(t) ¼ Seed(t À dt) + (Allocation_to_seed) * dt
INIT Seed ¼ 0
INFLOWS:
Allocation_to_seed ¼ (1Àseed__Switch_control) * (1Àseed__Switch_control_2)
* Assimilates * percent_to_seed
Stem(t) ¼ Stem(t À dt) + (Allocation_to_stem) * dt
INIT Stem ¼ 0.1
INFLOWS:
Allocation_to_stem ¼ if time <¼ 1800 then Assimilates * percent_to_stem * root_
shoot__switch else 0
Daily_cycle ¼ (TIME MOD 24)+1
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20 Soybean Plant Growth