Garden with Insight v1.0 Help: Nitrogen  Denitrification
As one of the microbial processes, denitrification is a function of temperature and water content. The
equation used to estimate the denitrification rate is [Equation 170] where DN is the denitrification rate in
later l in kg/ha*day, TF(n) is the nutrient cycling temperature factor, C is the organic carbon content in
percent, and SWF is the soil water factor.
Equation 170
SWF = SW / FC
if SWF >= 0.95, DN = WNO3 * (1.0  exp(1.4 * TF(n) * C))
else DN = 0
Code:
if SWF >= 0.95, DN = WNO3 * (1.0  exp(1.4 * TF(n) * OM / SWT))
OM / SWT does NOT = C, because in other places in the code,
the relationship C = (OM / 1.72) / SWT * 0.01 is used.
Variables:
DN = DenitrificationForLayer_kgPha
SWF = soilWaterOverFieldCapacity
WNO3 = nitrate_kgPha
TF(n) = nutrientCyclingTempFactor
C = organicC_pct
OM = organicMatter_tPha
SWT = weight_tPha
The temperature factor is expressed by the equation [Equation 171] where T is soil temperature in degrees
C and subscript l refers to the layers.
Equation 171
TF(n) = max(0.1, T / (T + exp(9.93  0.312 * T)))
Code:
TF(n) = T / (T + 20551.0 * exp(0.312 * T))
but since exp(9.93) = 20551, this is the same
code does not have bound
Variables:
TF(n) = NutrientCyclingTempFactorForLayer
T = temperature_degC
The soil water factor considers total soil water in the equation [Equation 172] where SW is the soil water
content in layer l and FC is the field capacity in mm.
Equation 172
SWF = SW / FC
Code:
same
Variables:
SWF = SoilWaterOverFieldCapacityForLayer
SW = waterContent_mm
FC = fieldCapacity_mm
