RUFAS.routines.field.soil.nitrogen_cycling.nitrification_volatilization module

class RUFAS.routines.field.soil.nitrogen_cycling.nitrification_volatilization.NitrificationVolatilization(soil_data: SoilData | None = None, field_size: float | None = None)

Bases: object

Manages the nitrification and volatilization operations for the ammonium pool, in accordance with SWAT section 3:1.3.

Parameters

soil_dataSoilData, optional

The SoilData object used by this module for tracking the nitrification and volatilization of ammonium in the soil. If not provided, a new SoilData object will be instantiated.

field_sizefloat, optional

The size of the field in hectares (ha), used to initialize a SoilData object if one is not directly provided.

Attributes

dataSoilData

Holds the SoilData object for tracking nitrification and volatilization processes.

Notes

The provision of a field size is crucial when a pre-configured SoilData object is not available, as it enables the initialization of a SoilData object. This allows for the simulation of nitrification and volatilization processes specific to the given field size.

__init__(soil_data: SoilData | None = None, field_size: float | None = None)

do_daily_nitrification_and_volatilization() → None

Conducts the nitrification and volatilization of ammonium within the soil profile on a daily basis.

Notes

This method uses the nutrient_cycling_water_factor calculated by LayerData, instead of the water factor that SWAT specifies for use in calculating denitrification/volatilization (see SWAT Theoretical documentation eqn. 3:1.3.2, 3).

References

SWAT Theoretical documentation section 3:1.3

static _calculate_nitrification_volatilization_temp_factor(temperature: float) → float

Calculates the nitrification/volatilization temperature factor.

Parameters

temperaturefloat

Current temperature of the soil layer (degrees C).

Returns

float

The nitrification/volatilization temperature factor of the current layer of soil (unitless).

Notes

SWAT does not explicitly say that this temperature factor should be upper-bounded at 1.0, but after discussion with Pete Vadas it came to light that this factor needs to have an upper bound.

References

SWAT Theoretical documentation eqn. 3:1.3.1

static _calculate_nitrification_soil_water_factor(water_content: float, wilting_point: float, field_capacity: float) → float

Calculates the soil water factor for nitrification.

Parameters

water_contentfloat

Water present in this soil layer (mm).

wilting_pointfloat

Amount of water in this soil layer when at wilting point (mm).

field_capacityfloat

Amount of water in this soil layer when at field capacity (mm).

Returns

float

The nitrification soil water factor (unitless).

Notes

The SWAT documentation for this equation appears to be misaligned with its implementation, see the file nitvol.f (https://bitbucket.org/blacklandgrasslandmodels/swat_development/src/master/nitvol.f).

References

SWAT Theoretical documentation eqn. 3:1.3.2, 3

static _calculate_volatilization_depth_factor(depth: float) → float

Calculates the depth factor for use in determining volatilization.

Parameters

depthfloat

The depth of the center of this soil layer (mm).

Returns

float

The volatilization depth factor (unitless).

References

SWAT Theoretical documentation eqn. 3:1.3.4

static _calculate_nitrification_regulator(temp_factor: float, water_factor: float) → float

Calculates the nitrification regulator for this layer of soil.

Parameters

temp_factorfloat

The nitrification/volatilization temperature factor of the current layer of soil (unitless).

water_factorfloat

The nitrification soil water factor of the current soil layer (unitless).

Returns

float

The nitrification regulator for this layer of soil (unitless).

References

SWAT Theoretical documentation eqn. 3:1.3.6

static _calculate_volatilization_regulator(temp_factor: float, depth_factor: float, cation_exchange_factor: float) → float

Calculates the volatilization regulator for this layer of soil.

Parameters

temp_factorfloat

The nitrification/volatilization temperature factor of the current layer of soil (unitless).

depth_factorfloat

The volatilization depth factor (unitless).

cation_exchange_factorfloat

The volatilization cation exchange factor (unitless).

Returns

float

The volatilization regulator for this layer of soil (unitless).

References

SWAT Theoretical documentation eqn. 3:1.3.7

static _calculate_total_ammonium_lost(ammonium_content: float, nitrification_regulator: float, volatilization_regulator: float) → float

Calculates the amount of ammonium lost to nitrification and volatilization.

Parameters

ammonium_contentfloat

The ammonium content of this soil layer (kg / ha).

nitrification_regulatorfloat

The nitrification regulator for this layer of soil (unitless).

volatilization_regulatorfloat

The volatilization regulator for this layer of soil (unitless).

Returns

float

The amount of ammonium lost to nitrification and volatilization (kg / ha).

References

SWAT Theoretical documentation eqn. 3:1.3.8

static _calculate_ammonium_loss_fraction(regulator: float) → float

Calculates the fraction of lost ammonium that is lost to the specified process.

Parameters

regulatorfloat

The regulator for the process that ammonium is being lost to (unitless).

Returns

float

Fraction of lost ammonium that is lost due to the given process (unitless).

References

SWAT Theoretical documentation eqn. 3:1.3.9, 10

Notes

This method is used to calculate the fraction of ammonium lost to both nitrification and volatilization.

static _calculate_ammonium_lost_to_process(total_lost_ammonium: float, actual_loss_fraction: float, other_loss_fraction: float) → float

Calculates the amount of ammonium lost to the specified process.

Parameters

total_lost_ammoniumfloat

The total ammonium content lost to nitrification and volatilization (kg / ha).

actual_loss_fractionfloat

The loss fraction for the specified process that ammonium is being lost to (unitless).

other_loss_fractionfloat

The loss fraction for the other process that ammonium is lost to (unitless).

Returns

float

The amount of ammonium that is lost to the specified process (kg / ha).

References

SWAT Theoretical documentation eqn. 3:1.3.11, 12

Notes

This method is intended to be used to calculate both the amount of ammonium lost to nitrification and to volatilization. To calculate the amount lost to nitrification, pass the nitrification loss fraction as the actual_loss_fraction and the volatilization loss fraction as the other_loss_fraction, and vice versa for calculating the amount lost to volatilization.