Garden with Insight v1.0 Help: stress/constraint
A stress or constraint on plant growth is anything that reduces plant growth from the optimal. Plants in shade are stressed, as are plants near polluting stacks or
drowned by silt near a river. Much work is being done to study the effects of various stresses, many
human-made, on plant growth.
In this simulation, there are two sets of stresses simulated: for general growth and for root growth. Each
stress factor (or growth constraint) ranges from zero to one. Because
these factors are used to reduce new growth by multiplication, a factor of one is best and a factor of zero is
The above ground stresses are: temperature stress (caused by too high or too low temperatures), water
stress (caused by lack of soil water), aeration stress (caused by too little
air in the soil), nitrogen stress (caused by not enough nitrate in the
soil), and phosphorus stress (caused by not enough labile P in the soil).
The combined growth constraint for general growth is the smallest (worst) of these factors.
The root stresses for each soil layer are: temperature stress (a different
equation than the general temperature stress), aluminum toxicity stress (caused by too many aluminum
Al3+ ions in the soil), and soil strength stress (caused by too much soil
compaction). The combined growth constraint for root growth is the smallest (worst) of these factors.