RUFAS.routines.field.field.manure_application module

RUFAS.routines.field.field.manure_application.FRESH_FRACTION_OF_ORGANIC_NITROGEN = 0.9286

This fraction was used in the evaluation of RuFaS Soil Nitrogen cycling, and was validated empirically.

RUFAS.routines.field.field.manure_application.SOIL_INFILTRATION = 0.6

Surphos assumes infiltration of 60% of nutrients from manure with less than 15% dry matter

class RUFAS.routines.field.field.manure_application.ManureApplication(soil_data: SoilData | None = None, field_size: float | None = None)

Bases: object

This class contains all necessary methods for adding new applications for manure phosphorus to a field, based on the SurPhos model.

Parameters

soil_dataSoilData, optional

The SoilData object used by this module to track manure phosphorus activity, creates new one if one is not provided.

field_sizefloat, optional

Used to initialize a SoilData object for this module to work with, if a pre-configured SoilData object is not provided (ha).

Attributes

dataSoilData

Reference to the SoilData object that is being tracked

Methods

apply_grazing_manure(dry_matter_mass: float, dry_matter_fraction: float, total_phosphorus_mass: float,

inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, field_size: float) -> None

This method takes a new application of machine-applied manure phosphorus and adds it to the existing pool to be tracked.

apply_machine_manure(dry_matter_mass: float, dry_matter_fraction: float,

total_phosphorus_mass: float, field_coverage: float, application_depth: float, surface_remainder_fraction: float, field_size: float, inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, water_extractable_inorganic_phosphorus_fraction: float = None, source_animal: str = None) -> None

This method takes a new application of machine-applied manure phosphorus and adds it to the existing pool to be tracked.

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

apply_grazing_manure(dry_matter_mass: float, dry_matter_fraction: float, total_phosphorus_mass: float, inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, field_size: float) → None

This method takes a new application of machine-applied manure phosphorus and adds it to the existing pool to

be tracked.

Parameters

dry_matter_massfloat

Dry weight equivalent of this application (kg).

dry_matter_fractionfloat

Fraction of this manure application that is dry matter, in the range (0.0, 1.0] (unitless).

total_phosphorus_massfloat

Total mass of phosphorus in this application of manure (kg).

inorganic_nitrogen_fractionfloat

Fraction of dry manure mass that is inorganic nitrogen (unitless).

ammonium_fractionfloat

Fraction of inorganic nitrogen that is ammonium (unitless).

organic_nitrogen_fractionfloat

Fraction of dry manure mass that is organic nitrogen (unitless).

field_sizefloat

Size of the field (ha).

Notes

The hardcoded values that determine the distribution of phosphorus between the water extractable inorganic/organic and stable inorganic/organic pools are listed in the SurPhos theoretical documentation page 7, in the paragraph immediately following the head “Simulation of Grazing Manure Transforms”.

apply_machine_manure(dry_matter_mass: float, dry_matter_fraction: float, total_phosphorus_mass: float, field_coverage: float, application_depth: float, surface_remainder_fraction: float, field_size: float, inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, water_extractable_inorganic_phosphorus_fraction: float | None = None, source_animal: str | None = None) → None

This method takes a new application of machine-applied manure phosphorus and adds it to the existing pool to

be tracked.

Parameters

dry_matter_massfloat

Dry weight equivalent of this application (kg).

dry_matter_fractionfloat

Fraction of this manure application that is dry matter, in the range (0.0, 1.0] (unitless).

total_phosphorus_massfloat

Total mass of phosphorus in this application of manure (kg).

field_coveragefloat

Fraction of the field this manure is applied to (unitless).

application_depthfloat

Depth at which fertilizer is injected into the soil (mm).

surface_remainder_fractionfloat

Fraction of fertilizer applied that remains on the soil surface after application (unitless).

field_sizefloat

Size of the field (ha).

inorganic_nitrogen_fractionfloat

Fraction of dry manure mass that is inorganic nitrogen (unitless).

ammonium_fractionfloat

Fraction of inorganic nitrogen that is ammonium (unitless).

organic_nitrogen_fractionfloat

Fraction of dry manure mass that is organic nitrogen (unitless).

water_extractable_inorganic_phosphorus_fractionfloat, default=None

Fraction of total phosphorus in this application of manure that is water extractable inorganic phosphorus, in the range [0.0, 1.0] (unitless).

source_animalstr, default=None

Type of animal that produced this manure (options are “CATTLE”, “SWINE”, or “POULTRY”) (unitless).

Raises

ValueError

If the water extractable inorganic phosphorus fraction is not inside the range [0.0, 0.95].

Notes

When manure is applied that contains 15% or less solid matter, the slurry immediately infiltrates the soil. The SurPhos theoretical documentation states that “the model assumes slurry liquid immediately infiltrates into soil and adds 60% of all manure P to corresponding soil P pools”.

_add_nitrogen_to_soil_layer(layer_index: int, dry_matter_mass: float, inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, field_size: float) → None

Adds nitrogen into the top of the soil profile when manure is applied to the field.

Parameters

layer_indexint

Index of the soil layer to be added to (unitless).

dry_matter_massfloat

Dry weight equivalent of this application (kg).

inorganic_nitrogen_fractionfloat

Fraction of dry manure mass that is inorganic nitrogen (unitless).

ammonium_fractionfloat

Fraction of inorganic nitrogen that is ammonium (unitless).

organic_nitrogen_fractionfloat

Fraction of dry manure mass that is organic nitrogen (unitless).

field_sizefloat

Size of the field (ha).

References

SWAT Theoretical documentation section 6:1.7 pseudocode_field_management [FM.4.D.1]

Notes

This method allows nitrogen to be added to any soil layer in the profile by specifying the index of that layer. The top soil layer will always be at index 0.

Instead of partitioning organic nitrogen between the fresh and active pools, it is partitioned between the stable and active pools. Refer to the pseudocode for this.

_apply_subsurface_manure(total_phosphorus_mass: float, water_extractable_inorganic_phosphorus_fraction: float, water_extractable_organic_phosphorus_fraction: float, stable_inorganic_phosphorus_fraction: float, stable_organic_phosphorus_fraction: float, dry_matter_mass: float, inorganic_nitrogen_fraction: float, ammonium_fraction: float, organic_nitrogen_fraction: float, application_depth: float, subsurface_fraction: float, field_size: float) → None

Applies subsurface nutrients to the soil profile.

Parameters

total_phosphorus_massfloat

Total mass of phosphorus in this application of manure (kg).

water_extractable_inorganic_phosphorus_fractionfloat

Fraction of total phosphorus in this application of manure that is water extractable inorganic phosphorus, in the range [0.0, 1.0] (unitless).

water_extractable_organic_phosphorus_fractionfloat

Fraction of total phosphorus in this application of manure that is water extractable organic phosphorus, in the range [0.0, 1.0] (unitless).

stable_inorganic_phosphorus_fractionfloat

Fraction of total phosphorus in this application of manure that is stable inorganic phosphorus, in the range [0.0, 1.0] (unitless).

stable_organic_phosphorus_fractionfloat

Fraction of total phosphorus in this application of manure that is stable organic phosphorus, in the range [0.0, 1.0] (unitless).

dry_matter_massfloat

Dry weight equivalent of the manure application (kg).

inorganic_nitrogen_fractionfloat

Fraction of dry manure mass that is inorganic nitrogen (unitless).

ammonium_fractionfloat

Fraction of inorganic nitrogen that is ammonium (unitless).

organic_nitrogen_fractionfloat

Fraction of dry manure mass that is organic nitrogen (unitless).

application_depthfloat

Depth at which fertilizer is injected into the soil (mm).

subsurface_fractionfloat

Fraction of total manure application that is applied below the soil surface (unitless).

field_sizefloat

Size of the field (ha).

Notes

Only 95% of water extractable organic and stable organic phosphorus are put into their corresponding pools because that is how SurPhos transfers organic phosphorus, as an approximation for organic phosphorus loss. This practice will be changed when issue #444 is addressed.

static _determine_grazing_manure_field_coverage(field_size: float, total_manure_applied: float) → float

Calculates the fraction of the field covered by manure that was applied by grazers.

Parameters

field_sizefloat

Size of the field (ha)

total_manure_appliedfloat

Total mass of the manure application (kg)

Returns

float

The fraction of the field covered by manure (unitless)

Notes

This method is only used for calculating the field coverage for manure applied by grazers. It is based on the relationship specified in the SurPhos theoretical documentation which states that the ratio is 250 grams of manure to 659 square centimeters of field coverage (James et al., 2007).

References

James E., Kleinman P., Veith T., Stedman R., Sharpley A. (2007) Phosphorus contributions from

pastured dairy cattle to streams of the Cannonsville Watershed, New York. Journal of Soil and Water Conservation 62:40-47.

static _determine_moisture_factor(dry_matter_fraction: float) → float

This method determines the moisture factor of a new manure application based on how much manure was applied

and how much water was in the application.

Parameters

dry_matter_fractionfloat

Fraction of this manure application that is dry matter, in the range (0.0, 1.0] (unitless)

Returns

float

The moisture factor of this application of manure (unitless)

Raises

ValueError

If the dry matter content is not inside the range (0.0, 1.0]

Notes

This equation is not listed in the SurPhos theoretical documentation, but is present in both the SurPhos Python and Fortran code (see manure.f and manure.py, lines 30, 31 and 41, 42 respectively). This equation is a way of determining the moisture factor based on the amount of dry matter mass in the manure application that produces more accurate results.

static _determine_weighted_manure_attributes(old_total_dry_mass: float, old_moisture_factor: float, old_field_coverage: float, application_dry_mass: float, application_dry_fraction: float, application_field_coverage: float) → Dict

Recalculates the manure pool attributes that use a weighted average to find their new values.

Parameters

old_total_dry_massfloat

Dry weight equivalent of the manure that was already on the field (kg)

old_moisture_factorfloat

Moisture factor of the manure that was already on the field, between [0, 0.9] (unitless)

old_field_coveragefloat

The fraction of the area of the field that was already covered by old manure, between [0, 1] (unitless)

application_dry_massfloat

Dry weight equivalent of manure application (kg)

application_dry_fractionfloat

Fraction of this manure application that is dry matter, in the range (0.0, 1.0] (unitless)

application_field_coveragefloat

Fraction of the field covered by the manure application (unitless)

Returns

new_dry_matter_massfloat

The new dry weight equivalent of manure on the field (kg)

new_moisture_factorfloat

The new moisture factor of the manure on the field, in the range [0, 0.9] (unitless)

new_field_coveragefloat

The new fraction of field area that is covered by manure, in the range [0, 1] (unitless)

Notes

To keep a more accurate state of the manure and grazing phosphorus pools, the field coverage and moisture variables are recalculated to be a weighted average of the new and preexisting field coverage and moisture variables, weighted by mass.

static _determine_water_extractable_inorganic_phosphorus_fraction_by_animal(animal_type: str | None) → float

Parameters

animal_typestr

Type of animal that produced the manure (can be either “CATTLE”, “SWINE”, or “POULTRY”)

Returns

float

Fraction of manure that is water-extractable inorganic phosphorus (unitless)

Raises

ValueError

If the animal type passed does not match any of the supported types.

Notes

These are reasonable defaults provided Pete Vadas.