Choice of activity data

There are two main types of activity data for estimating N2O emissions from manure management systems: (1) livestock population data, and (2) manure management system usage data.

Livestock population data, N(T)

The animal population data should be obtained using the approach described in Section 10.2. If using default nitrogen excretion rates to estimate N2O emissions from manure management systems, a Tier 1 livestock population characterisation is sufficient. To estimate N2O emissions from Manure Management using calculated nitrogen excretion rates, a Tier 2 characterisation must be performed. As noted in Section 10.2, good practice in characterising livestock populations is to conduct a single characterisation that will provide the activity data for all emissions sources that depend on livestock population data.

Manure management system usage data, MS(T,S)

The manure management system usage data used to estimate N2O emissions from Manure Management should be the same as those that are used to estimate CH4 emissions from Manure Management (see Table 10.18 for a summary of the main types of manure management systems). The portion of manure managed in each manure management system must be collected for each representative livestock category. Note that in some cases, manure may be managed in several types of manure management systems. For example, manure flushed from a dairy freestall barn to an anaerobic lagoon may first pass through a solids separation unit where some of the manure solids are removed and managed as a solid. Therefore, it is important to carefully consider the fraction of manure that is managed in each type of system.

The best means of obtaining manure management system distribution data is to consult regularly published national statistics. If such statistics are unavailable, the preferred alternative is to conduct an independent survey of manure management system usage. If the resources are not available to conduct a survey, experts should be consulted to obtain an opinion of the system distribution. If country-specific manure management system usage data are not available, default values should be used. The IPCC default values for dairy cows, other cattle, buffalo, swine (market and breeding swine), and poultry should be taken from Tables 10A-4 through 10A-8 of Annex 10A.2. Manure from other animal categories is typically managed in pastures and grazing operations.

Table 10.21

Default emission factors for direct N20 emissions from manure management

System

Definition

[kg N2O-N (kg Nitrogen excreted)-1]

Uncertainty ranges of EF3

Sourcea

Pasture/Range/ Paddock

The manure from pasture and range grazing animals is allowed to lie as is, and is not managed.

Direct and indirect N2O emissions associated with the manure deposited on agricultural soils and pasture, range, paddock systems are treated in Chapter 11, Section 11.2, N2O emissions from managed soils.

Daily spread

Manure is routinely removed from a confinement facility and is applied to cropland or pasture within 24 hours of excretion. N2O emissions during storage and treatment are assumed to be zero. N2O emissions from land application are covered under the Agricultural Soils category.

0

Not applicable

Judgement by IPCC Expert Group (see Co-chairs, Editors and Experts; N2O emissions from Manure Management).

Solid storageb

The storage of manure, typically for a period of several months, in unconfined piles or stacks. Manure is able to be stacked due to the presence of a sufficient amount of bedding material or loss of moisture by evaporation.

0.005

Factor of 2

Judgement of IPCC Expert Group in combination with Amon et al. (2001), which shows emissions ranging from 0.0027 to 0.01 kg N2O-N (kg N)-1.

Dry lot

A paved or unpaved open confinement area without any significant vegetative cover where accumulating manure may be removed periodically. Dry lots are most typically found in dry climates but also are used in humid climates.

0.02

Factor of 2

Judgement of IPCC Expert Group in combination with Kulling (2003).

With natural crust cover

0.005

Factor of 2

Judgement of IPCC Expert Group in combination with Sommer et al. (2000).

Liquid/Slurry

Manure is stored as excreted or with some minimal addition of water to facilitate handling and is stored in either tanks or earthen ponds.

Without natural crust cover

0

Not applicable

Judgement of IPCC Expert Group in combination with the following studies: Harper et al. (2000), Lague et al. (2004), Monteny et al. (2001), and Wagner-Riddle and Marinier (2003). Emissions are believed negligible based on the absence of oxidized forms of nitrogen entering systems in combination with low potential for nitrification and denitrification in the system.

Uncovered anaerobic lagoon

Anaerobic lagoons are designed and operated to combine waste stabilization and storage. Lagoon supernatant is usually used to remove manure from the associated confinement facilities to the lagoon. Anaerobic lagoons are designed with varying lengths of storage (up to a year or greater), depending on the climate region, the volatile solids loading rate, and other operational factors. The water from the lagoon may be recycled as flush water or used to irrigate and fertilise fields.

0

Not applicable

Judgement of IPCC Expert Group in combination with the following studies: Harper et al. (2000), Lague et al. (2004), Monteny et al. (2001), and Wagner-Riddle and Marinier (2003). Emissions are believed negligible based on the absence of oxidized forms of nitrogen entering systems in combination with low potential for nitrification and denitrification in the system.

Pit storage below animal confinements

Collection and storage of manure usually with little or no added water typically below a slatted floor in an enclosed animal confinement facility.

0.002

Factor of 2

Judgement of IPCC Expert Group in combination with the following studies: Amon et al. (2001), Kulling (2003), and Sneath et al. (1997).

Table 10.21 (continued) Default emission factors for direct N2O emissions from manure management

System

Definition

[kg N2O-N (kg Nitrogen excreted)-1]

Uncertainty ranges of EF3

Sourcea

Anaerobic digester

Anaerobic digesters are designed and operated for waste stabilization by the microbial reduction of complex organic compounds to CH4 and CO2, which is captured and flared or used as a fuel.

0

Not applicable

Judgement of IPCC Expert Group in combination with the following studies: Harper et al. (2000), Lague et al. (2004) Monteny et al. (2001), and Wagner-Riddle and Marinier (2003). Emissions are believed negligible based on the absence of oxidized forms of nitrogen entering systems in combination with low potential for nitrification and denitrification in the system.

Burned for fuel or as waste

The dung is excreted on fields. The sun dried dung cakes are burned for fuel.

The emissions associated with the burning of the dung are to be reported under the IPCC category 'Fuel Combustion' if the dung is used as fuel and under the IPCC category 'Waste Incineration' if the dung is burned without energy recovery.

Urine N deposited on pasture and paddock

Direct and indirect N2O emissions associated with the urine deposited on agricultural soils and pasture, range, paddock systems are treated in Chapter 11, Section 11.2, N2O emissions from managed soils.

As manure accumulates, bedding is continually added to absorb moisture over a production cycle and possibly for as long as 6 to 12 months. This manure management system also is known as a bedded pack manure management system and may be combined with a dry lot or pasture.

No mixing

0.01

Factor of 2

Average value based on Sommer and Moller (2000), Sommer (2000), Amon et al. (1998), and Nicks et al. (2003).

Cattle and swine deep bedding

Active mixing

0.07

Factor of 2

Average value based on Nicks et al. (2003) and Moller et al. (2000). Some literature cites higher values to 20% for well maintained, active mixing, but those systems included treatment for ammonia which is not typical.

Composting -In-Vesselc

Composting, typically in an enclosed channel, with forced aeration and continuous mixing.

0.006

Factor of 2

Judgement of IPCC Expert Group. Expected to be similar to static piles.

Composting -Static Pilec

Composting in piles with forced aeration but no mixing.

0.006

Factor of 2

Hao et al. (2001).

Composting -

Intensive

Windrowc

Composting in windrows with regular turning for mixing and aeration.

0.1

Factor of 2

Judgement of IPCC Expert Group. Expected to be greater than passive windrows and intensive composting operations, as emissions are a function of the turning frequency.

Composting -

Passive

Windrowc

Composting in windrows with infrequent turning for mixing and aeration.

0.01

Factor of 2

Hao et al. (2001).

Poultry manure with litter

Similar to deep bedding systems. Typically used for all poultry breeder flocks and for the production of meat type chickens (broilers) and other fowl.

0.001

Factor of 2

Judgement of IPCC Expert Group based on the high loss of ammonia from these systems, which limits the availability of nitrogen for nitrification/denitrification.

Poultry manure without litter

May be similar to open pits in enclosed animal confinement facilities or may be designed and operated to dry the manure as it accumulates. The latter is known as a high-rise manure management system and is a form of passive windrow composting when designed and operated properly.

0.001

Factor of 2

Judgement of IPCC Expert Group based on the high loss of ammonia from these systems, which limits the availability of nitrogen for nitrification/denitrification.

Table 10.21 (continued) Default emission factors for direct N2O emissions from manure management

System

Definition

[kg N2O-N (kg Nitrogen excreted)-1]

Uncertainty ranges of EF3

Source3

Aerobic treatment

The biological oxidation of manure collected as a liquid with either forced or natural aeration. Natural aeration is limited to aerobic and facultative ponds and wetland systems and is due primarily to photosynthesis. Hence, these systems typically become anoxic during periods without sunlight.

Natural aeration systems

0.01

Factor of 2

Judgement of IPCC Expert Group. Nitrification-denitrification is used widely for the removal of nitrogen in the biological treatment of municipal and industrial wastewaters with negligible N2O emissions. Limited oxidation may increase emissions compared to forced aeration systems.

Forced aeration systems

0.005

Factor of 2

Judgement of IPCC Expert Group. Nitrification-denitrification is used widely for the removal of nitrogen in the biological treatment of municipal and industrial wastewaters with negligible N2O emissions.

aAlso see Dustan (2002), which compiled information from some of the original references cited.

b Quantitative data should be used to distinguish whether the system is judged to be a solid storage or liquid/slurry. The borderline between dry and liquid can be drawn at 20% dry matter content.

c Composting is the biological oxidation of a solid waste including manure usually with bedding or another organic carbon source typically at thermophilic temperatures produced by microbial heat production.

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