Garden with Insight v1.0 Help: Plant Growth - Heat unit accumulation
Phenological development of the crop is based on daily heat unit accumulation. It is computed by using
the equation [Equation 253] where HU, T(mx) and T(mn) are the values of heat units, maximum
temperature, and minimum temperature in degrees C on day k, and T(b) is the crop-specific base
temperature in degrees C (no growth occurs at or below T(b)) of crop j.
Equation 253
HU = (T(mx) + T(mn)) / 2 - T(b)
HU >= 0
Code:
same
Variables:
HU = HeatUnitAccumulationForDay
T(mx) = maxTempForDay_degC
T(mn) = minTempForDay_degC
T(b) = baseTempForCrop_degC
Heat unit index
A heat unit index (HUI) ranging from 0 at planting to 1.0 at physiological maturity is computed as
follows [Equation 254] where HUI is the heat unit index for day i and PHU is the potential heat units
required for the maturation of crop j. The value of PHU may be inputted or calculated by the model from
normal planting and harvest dates. Date of harvest, leaf area growth and senescence, optimum plant
nutrient concentrations, and partition of dry matter among roots, shoots, and economic yield are affected
by HUI.
Equation 254
HUI = HU / PHU
Code:
same
Variables:
HUI = HeatUnitIndex
HU = cumHeatUnits
PHU = heatUnitsAtMaturation
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