RUFAS.routines.field.crop.nitrogen_uptake module

class RUFAS.routines.field.crop.nitrogen_uptake.NitrogenUptake(crop_data: CropData | None = None, nutrient_distro_param: float = 10.0, nutrient_shapes: list[float] | None = None, previous_nutrient: float | None = None, potential_nutrient_uptake: float | None = None, layer_nutrient_potentials: float | None = None, unmet_nutrient_demands: float | None = None, nutrient_requests: float | None = None, actual_nutrient_uptakes: list[float] | None = None, total_nutrient_uptake: float | None = None, fixed_nitrogen: float | None = None, nitrate_factor: float | None = None, fixation_stage_factor: float | None = None)

Bases: NonWaterUptake

Manages nitrogen incorporation in crops.

Parameters

crop_dataOptional[CropData], optional

An instance of CropData containing crop specifications and attributes. Defaults to a new instance of CropData if not provided.

nutrient_distro_paramfloat, default 10.0

Nitrogen uptake distribution parameter (unitless).

nutrient_shapesOptional[List[float]], default None

Shape coefficients for nitrogen uptake equations (unitless).

previous_nutrient: Optional[float], default None

Nitrogen in biomass on the previous day (kg/ha).

potential_nutrient_uptakeOptional[float], default None

Potential nitrogen uptake under ideal conditions (kg/ha).

layer_nutrient_potentialsOptional[float], default None

Potential nitrogen uptake from each soil layer (kg/ha).

unmet_nutrient_demandsOptional[float], default None

Unmet nitrogen demands by overlaying soil layers (kg/ha).

nutrient_requestsOptional[float], default None

Nitrogen requested from each soil layer (kg/ha).

actual_nutrient_uptakesOptional[List[float]], default None

Actual nitrogen uptake from each soil layer (kg/ha).

total_nutrient_uptakeOptional[float], default None

Total nitrogen uptake by the plant (kg/ha).

fixed_nitrogenOptional[float], default None

Total nitrogen fixed by the plant (kg/ha).

nitrate_factorOptional[float], default None

Soil nitrate factor (unitless).

fixation_stage_factorOptional[float], default None

Growth stage factor for nitrogen-fixing symbiotes (unitless).

Attributes

nutrient_distro_paramfloat

Nitrogen uptake distribution parameter (unitless).

nutrient_shapesOptional[List[float]]

Shape coefficients for nitrogen uptake equations (unitless).

previous_nutrientOptional[float]

Nitrogen in biomass on the previous day (kg/ha).

potential_nutrient_uptakeOptional[float]

Potential nitrogen uptake under ideal conditions (kg/ha).

layer_nutrient_potentialsOptional[float]

Potential nitrogen uptake from each soil layer (kg/ha).

unmet_nutrient_demandsOptional[float]

Unmet nitrogen demands by overlaying soil layers (kg/ha).

nutrient_requestsOptional[float]

Nitrogen requested from each soil layer (kg/ha).

actual_nutrient_uptakesOptional[List[float]]

Actual nitrogen uptake from each soil layer (kg/ha).

total_nutrient_uptakeOptional[float]

Total nitrogen uptake by the plant (kg/ha).

fixed_nitrogenOptional[float]

Total nitrogen fixed by the plant (kg/ha).

nitrate_factorOptional[float]

Soil nitrate factor (unitless).

fixation_stage_factorOptional[float]

Growth stage factor for nitrogen-fixing symbiotes (unitless).

References

‘Nitrogen Uptake’ section (5:2.3.1) of the SWAT model.

__init__(crop_data: CropData | None = None, nutrient_distro_param: float = 10.0, nutrient_shapes: list[float] | None = None, previous_nutrient: float | None = None, potential_nutrient_uptake: float | None = None, layer_nutrient_potentials: float | None = None, unmet_nutrient_demands: float | None = None, nutrient_requests: float | None = None, actual_nutrient_uptakes: list[float] | None = None, total_nutrient_uptake: float | None = None, fixed_nitrogen: float | None = None, nitrate_factor: float | None = None, fixation_stage_factor: float | None = None)

uptake(soil_data: SoilData) → None

Main nitrogen incorporation function that runs all nitrogen processes and stores nitrogen as biomass.

Parameters

soil_dataSoilData

The SoilData object that tracks soil properties and nitrogen content.

Notes

Calling this function executes all nitrogen incorporation routines. It calculates the amount of nitrogen the plant desires based on its current growth stage and the available nitrogen in the soil. The function then extracts nitrogen from the accessible soil profile. If there’s any unmet nitrogen demand, the plant may attempt to fix atmospheric nitrogen. The nitrogen from both extraction and fixation is then added to the plant’s biomass, contributing to its growth.

try_fixation(total_accessible_nitrates: float, soil_water_factor: float) → None

Attempts to fix nitrogen if the plant is capable of nitrogen fixation.

Parameters

total_accessible_nitratesfloat

The total amount of nitrates accessible to the plant’s roots (kg/ha).

soil_water_factorfloat

A factor representing the availability of water in the soil, affecting the plant’s ability to fix nitrogen (unitless).

Notes

If the plant species is a nitrogen fixer, this method simulates the fixation of atmospheric nitrogen, enhancing the nitrogen content available to the plant. If the plant is not a nitrogen fixer, no action is taken, and the method does not affect the plant or soil properties. The humorous note implies that non-nitrogen fixing plants do not adversely affect themselves when this method is called.

update_fixation_attributes(total_accessible_nitrates: float) → None

Updates attributes necessary for nitrogen fixation.

Parameters

total_accessible_nitratesfloat

The total nitrates accessible to the plant’s roots.

fix_nitrogen(water_factor: float) → None

Fixes nitrogen, based on any remaining demand not met by actual uptake.

Parameters

water_factorfloat

A factor representing the availability of water in the soil, affecting the efficiency of nitrogen fixation (unitless).

static _determine_nitrate_factor(total_accessible_nitrates: float) → float

Calculates soil nitrate factor.

Parameters

total_accessible_nitratesfloat

Total nitrates available in the soil layers accessible to roots (kg nitrate / ha).

Returns

float

The soil nitrate factor, in the range [0.0, 1.0].

References

SWAT Theoretical documentation equations 5:2.3.15, 5:2.3.16, 5:2.3.17

Notes

Equation 5:2.3.16 in the SWAT Theoretical documentation (and associated SWAT code in the file nfix.f) is seemingly wrong. This equation originates from the EPIC model (see line 31 of NFIX.f90). Also note that in EPIC, the total accessible nitrates in the soil profile are divided by the amount of residue (RD(JKK)), which RuFaS does not do.

static _determine_fixation_stage_factor(heat_fraction: float) → float

Calculates the fixation symbiotic growth stage factor.

Parameters

heat_fractionfloat

The accumulated fraction of potential heat units (PHU).

Returns

float

The growth stage factor for symbiotic organisms involved in nitrogen fixation (unitless).

Notes

The symbiotic organisms that fix nitrogen exist at different densities depending upon the age of the plant. This growth stage factor reflects the density and activity level of these symbiotic organisms relative to the plant’s growth stage.

References

SWAT 2:2.3.10 - 2:2.3.14

static _determine_fixed_nitrogen(demand: float, stage_factor: float, water_factor: float, nitrate_factor: float) → float

Calculates the amount of nitrogen fixed by a plant.

Parameters

demandfloat

Nitrogen demand not met by uptake from soil (kg/ha).

stage_factorfloat

Growth stage factor, ranging from 0 to 1 (unitless).

water_factorfloat

Soil water factor, ranging from 0 to 1 (unitless).

nitrate_factorfloat

Soil nitrate factor, ranging from 0 to 1 (unitless).

Returns

float

The amount of nitrogen added to plant biomass through fixation, capped at the demand (kg/ha).

References

SWAT 5:2.3.9

_abc_impl = <_abc._abc_data object>