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Garden with Insight v1.0 Help: Plant daily growth constraints group

Combined growth constraint today: A factor from zero to one for the combined constraint on above-ground plant growth. Equal to the lowest (worst) of the above-ground growth constraints: temperature, aeration (waterlogging), water, N stress, or P stress. Multiplied by new biomass.

Temperature growth constraint today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to soil surface temperature. Truncated sine function with maximum at optimal temperature for this plant.

Water stress growth constraint today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to inadequate water uptake. Based on the ratio of actual water uptake to potential transpiration, since water uptake is always limited by transpiration (which draws the water up).

N growth constraint today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to inadequate nitrogen uptake. Based on the ratio of lifetime actual N uptake to optimal N uptake and modified by an S curve that determines the plant's tolerance of N and P stress.

P growth constraint today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to inadequate phosphorus uptake. Based on the ratio of lifetime actual P uptake to optimal P uptake and modified by an S curve that determines the plant's tolerance of N and P stress.
Aeration growth constraint today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to waterlogging of the soil, which limits root respiration. Depends on soil water content and porosity in top meter of soil, critical aeration factor for plant tolerance, and S curve.

Combined constraint on root growth today: A factor from zero to one for the combined constraint on root growth (separate for each soil layer). Equal to the lowest (worst) of the root growth constraints: temperature, aluminum toxicity, and soil strength. Reduces root biomass and water uptake.

Temperature constraint on root growth today: Constraint from 0 (worst) to 1 (best) on root growth due to soil temperature in each soil layer. A sine function with its maximum at the optimal temperature for this plant (so lower or higher temperatures produce a reduced (worse) factor).

Aluminum toxicity constraint on root growth today: Constraint from 0 (worst) to 1 (best) on above-ground plant growth due to aluminum toxicity (excess of aluminum cations). Depends on aluminum saturation of soil and plant parameter for tolerance of aluminum.

Soil strength constraint on root growth today: Constraint from 0 (worst) to 1 (best) on root growth due to soil strength, a soil's ability to be compressed without deforming. Soil strength is good for roads but bad for roots. It increases with bulk density, sand content, and water content.

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Updated: May 4, 1998. Questions/comments on site to webmaster@kurtz-fernhout.com.
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