Garden with Insight v1.0 Help: Plant next day functions: reduce biomass if water-stressed and senescent

The water stress growth constraint reduces new growth from photosynthesis if the soil is dry. As the plant ages (senesces), the simulation also reduces existing shoot biomass because the plant is less flexible in dealing with water stress as it ages. Only shoot biomass (in stems and leaves) is affected. The function to calculate the biomass loss uses the heat unit index to the fourth power, which causes the curve to ramp up around maturity (heat unit index = 1.0).

Of course, if there is no water stress, there is no reduction (this curve is with a constant water stress growth constaint of 0.8). In EPIC, this reduction in biomass only applies to perennial plants, but we changed it to apply to annuals also, because we want to simulate their slow dying-off.

calculation of water stress growth constraint
EPIC Loss of Senescent Plant Material
Model contents