# Model Documentation

### | Version 4.0

created with goxygen 0.21.1

# 55_awms

# Animal waste management systems (55_awms)

## Description

This module calculates the nutrient (NPK) flows within animal waste management. It receives information on feed from the module 70_livestock, and provides information on recycled manure to 50_nr_soil_budget and information on greenhouse gas emissions to modules 51_nitrogen and 53_methane.

## Interfaces

Interfaces to other modules

### Input

module inputs (A: ipcc2006_aug16 | B: off)
| Description | Unit | A | B
--- | --- | --- | --- | ---
fm_attributes (attributes, kall) | Conversion factors - where X is ton N P K C DM WM or PJ GE | \(X/tDM\) | x |
im_development_state (t, i) | Development state according to the World Bank definition where 0=low income country 1=high income country in high income level | \(1\) | x |
im_slaughter_feed_share (t_all, i, kap, attributes) | Share of feed that is incorporated in animal biomass | \(1\) | x |
vm_dem_feed (i, kap, kall) | Regional feed demand including byproducts | \(10^6 tDM/yr\) | x |

### Output

module outputs
| Description | Unit
--- | --- | ---
vm_manure_confinement (i, kli, awms_conf, npk) | Manure excreted in confinements managed in different awms | \(10^6 t X\)
vm_manure (i, kli, awms, npk) | Calculation of manure excreted in confinements | \(10^6 t X\)
vm_manure_recycling (i, npk) | Manure being recycled to croplands | \(10^6 t X\)

## Realizations

### (A) ipcc2006_aug16

Manure excretion is estimated using a mass balance approach and based on NPK in feed and N in slaughtered animals (Bodirsky et al. (2012).). Animal waste management is largely based on the IPCC 2006 Guidelines for National Greenhouse Gas Inventories (IPCC (2006).).

Manure is estimated based on feed intake minus the NPK incorporated in the biomass of the slaughtered animal. We distinguish 4 general animal waste management systems based on what animals eat and where their manure remains. For simplification, we assume that pastures receive the manure of grazed biomass, while croplands receive the manure of cropbased feed. In reality, manure from grazing may be also excreted in stables and vice versa. Problematic may be in particular that grass can also be harvested and fed to animals in stables, and manure from confinements may be applied also to pastures. As both practices mostly appear in high-income countries and may also be causally linked (as nutrient deficits of pastures have to be balanced if biomass is removed), we assume they cancel out. We therefore distinguish only 4 categories: a) confined animals which receive concentrate feed and crop residues

\[\begin{multline*} v55\_feed\_intake\left(i2, kli, "confinement",npk\right) = \sum_{kcr}\left(vm\_dem\_feed(i2,kli,kcr) \cdot fm\_attributes(npk,kcr)\right) + \sum_{kap}\left(vm\_dem\_feed(i2,kli,kap) \cdot fm\_attributes(npk,kap)\right) + \sum_{ksd}\left(vm\_dem\_feed(i2,kli,ksd) \cdot fm\_attributes(npk,ksd)\right) + \sum_{kres}\left(vm\_dem\_feed(i2,kli,kres) \cdot fm\_attributes(npk,kres) \cdot \left(1-\left(1-\sum_{ct}im\_development\_state(ct,i2)\right)\right) \cdot 0.25\right) \end{multline*}\]

2. grazing animals on pastures where the manure stays on pastures

\[\begin{multline*} v55\_feed\_intake\left(i2, kli, "grazing",npk\right) = vm\_dem\_feed(i2,kli,"pasture") \cdot fm\_attributes(npk,"pasture") \cdot \left(1-ic55\_manure\_fuel\_shr(i2,kli)\right) \end{multline*}\]

3. grazing animals on pastures where the manure is collected as household fuel

\[\begin{multline*} v55\_feed\_intake\left(i2, kli, "fuel",npk\right) = vm\_dem\_feed(i2,kli,"pasture") \cdot fm\_attributes(npk,"pasture") \cdot \sum_{ct}ic55\_manure\_fuel\_shr(i2,kli) \end{multline*}\]

4. grazing animals eating crop residues on stubble fields.

\[\begin{multline*} v55\_feed\_intake\left(i2, kli, "stubble\_grazing",npk\right) = \sum_{kres}\left(vm\_dem\_feed(i2,kli,kres) \cdot fm\_attributes(npk,kres) \cdot \left(1 - \sum\left(ct,im\_development\_state(ct,i2)\right)\right) \cdot 0.25\right) \end{multline*}\]

Please note that the share of residues fed via stubble grazing depends on the development state and has to be subtracted from the residues fed to confined animals. We assume that in developing regions 25% of residues are grazed by animals on stubble fields, whereas stubble grazing is assumed to not occur in developed regions. The manure is estimated by subtracting from feed a certain share which is incorporated into animal biomass. This share depends on the productivity of the animal and is calculated in the preprocessing, also for computational reasons.

\[\begin{multline*} vm\_manure\left(i2, kli, awms,npk\right) = v55\_feed\_intake\left(i2, kli, awms,npk\right) \cdot \left(1-\sum_{ct}im\_slaughter\_feed\_share(ct,i2,kli,npk)\right) \end{multline*}\]

Manure excreted in confinements is further distinguished into 9 animal waste management systems.

\[\begin{multline*} vm\_manure\_confinement\left(i2,kli,awms\_conf, npk\right) = vm\_manure\left(i2, kli, "confinement", npk\right) \cdot ic55\_awms\_shr(i2,kli,awms\_conf) \end{multline*}\]

Each of these awms have different recycling shares (and different emission factors, see 51_nitrogen)

\[\begin{multline*} vm\_manure\_recycling(i2,npk) = \sum_{awms\_conf,kli}\left( vm\_manure\_confinement\left(i2,kli,awms\_conf, npk\right) \cdot i55\_manure\_recycling\_share(i2,kli,awms\_conf,npk)\right) \end{multline*}\]

> Limitations There are no known limitations.

### (B) off

> Limitations There are no known limitations.

## Definitions

### Objects

module-internal objects (A: ipcc2006_aug16 | B: off)
| Description | Unit | A | B
--- | --- | --- | --- | ---
f55_awms_recycling_share (i, kli, awms_conf) | share of Nr in confinement recycled | \(tNr/tNr\) | x |
f55_awms_shr (t_all, i, scen_conf55, kli, awms_conf) | share of Nr in confinement recycled | \(tNr/tNr\) | x |
f55_manure_fuel_shr (t_all, i, kli, gdp_scen09) | share of Nr in confinement recycled | \(tNr/tNr\) | x |
i55_manure_recycling_share (i, kli, awms_conf, npk) | Share of manure recycled | \(tNr/tNr\) | x |
ic55_awms_shr (i, kli, awms_conf) | Share of manure Nr managed in each animal waste management systems | \(tNr/tNr\) | x |
ic55_manure_fuel_shr (i, kli) | Share of manure excreted on pastures used for fuel | \(tNr/tNr\) | x |
q55_bal_intake_confinement (i, kli, npk) | Nutrient balance for intake in confinement | \(10^6 t X\) | x |
q55_bal_intake_fuel (i, kli, npk) | Nutrient balance for intake of grazing animals on pasture whose excreate are collected for household fuel | \(10^6 t X\) | x |
q55_bal_intake_grazing_cropland (i, kli, npk) | Nutrient balance for intake of grazing animals on cropland | \(10^6 t X\) | x |
q55_bal_intake_grazing_pasture (i, kli, npk) | Nutrient balance for intake of grazing animals on pastures | \(10^6 t X\) | x |
q55_bal_manure (i, kli, awms, npk) | Calculation of manure | \(10^6 t X\) | x |
q55_manure_confinement (i, kli, awms_conf, npk) | Manure from animals in confinement managed in different awms | \(10^6 t X\) | x |
q55_manure_recycling (i, npk) | Manure from animals in confinement recycling to cropland | \(10^6 t X\) | x |
v55_feed_intake (i, kli, awms, npk) | Calculation of manure excreted in confinements | \(10^6 t X\) | x |

### Sets

sets in use
| description
--- | ---
attributes | Product attributes characterizing a product (such as weight or energy content)
awms | animal waste management systems
awms_conf | animal waste management systems in confinements
gdp_scen09 | GDP scenario
i | World regions
kall | All products in the sectoral version
kap(k) | Animal products
kli(kap) | Livestock products
npk(nutrients) | Plant nutrients
scen_conf55 | awms scenarios
t_all | 5-year time periods
t(t_all) | Simulated time periods

## Authors

Benjamin Leon Bodirsky

## See Also

09_drivers, 16_demand, 50_nr_soil_budget, 51_nitrogen, 53_methane, 70_livestock

## References

Bodirsky, Benjamin Leon, Alexander Popp, Isabelle Weindl, Jan Philipp Dietrich, Susanne Rolinski, Lena Scheiffele, Christoph Schmitz, and Hermann Lotze-Campen. 2012. “Current State and Future Scenarios of the Global Agricultural Nitrogen Cycle.” Biogeosciences Discuss. 9 (3): 2755–2821. doi:10.5194/bgd-9-2755-2012.

IPCC. 2006. “2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National Greenhouse Gas Inventories Programme.”