AM0113 CSG15 Appendix 1

APPENDIX 1

DERIVATION OF EMISSION FACTORS FOR THE INVENTORY OF AMMONIA EMISSIONS FOR UK AGRICULTURE

NB: All emission factors are given in terms of NH3-N.

Cited sources are either scientific publications or DEFRA project Final Reports (given by Project Code), which are available from DEFRA.

CATTLE

Grazing

  • A updated version of the relationship between N input (kg N/ha) and ammonia emission (g N.lu-1d-1) from cattle grazed swards (Jarvis & Bussink 1990) was used, including data from Jarvis et al. 1989, Bussink 1992 and 1994, Ledgard 1996 and IGER (OC9117).

N input / Jarvis et al. ‘89 / Bussink ‘92 / Bussink ‘94 / Ledgard ‘96 / IGER OC9117 / WA0652
150 / 2
150 / 20
200 / 7.5
200 / 7.7
210 / 20
210 / 14 / 11.64
250 / 12.73 / 12.73
280 / 32
280 / 32
400 / 32.73
420 / 38
420 / 36
420 / 22

550 / 42.27 / 33.64
550 / 36.54

Fitted relationship:y = -0.51+0.0742 x (r2 0.68)

Average N inputs for dairy grazing and beef grazing given by British Survey of Fertiliser Practice ( as 155 and 53 kg N.ha-1y-1, respectively, giving emission factors of 10.99 and 3.42 g N.lu-1d-1, respectively.

Land spreading

Slurry

  • EF’s derived from the relationship between slurry DM content and ammonia emission (as % TAN applied) given by Smith & Chambers (1995).

Fitted relationship: y = 5.4 x + 4.5

Data used:

Slurry DM % / Loss as % TAN applied / Source
Cattle slurry on grass / 9.2 / 74 / Pain et al. 1988
9.2 / 76
9.2 / 47
9.2 / 43
6.5 / 38 / Thompson et al. 1990a
4.1 / 34
6.4 / 43
6.4 / 29
6.5 / 49 / Thompson et al. 1990b
7.7 / 31
8.6 / 38
6.0 / 74
4.3 / 34
4.5 / 59 / IGER OC9117
2.9 / 28
4.1 / 38
9.4 / 37
9.4 / 59
4.1 / 15
5.3 / 28 / ADAS OC9117 (Bridgets)
Cattle slurry on arable / 3.1 / 8 / ADAS OC9117 (Bridgets)
3.2 / 15
Pig slurry on grass / 1.8 / 13 / Pain et al. 1988
4.7 / 7 / Pain et al. 1989
4.6 / 8
Pig slurry on arable / 1.3 / 17 / ADAS OC9117 (Elveden)
4.4 / 22

EF’s as follows: Slurry DM %EF (% TAN applied)

<4 (use 2)15

4 - 8 (use 6)37

>8 (use 10)59

Many new data are available and a review of this area is required. There is some evidence that different relationships exist for slurry applications to grassland and to arable land; this will be reviewed when more experimental data have been gathered.

This relationship is used for slurry spread between August and April. For summer applications an EF of 60% is used, irrespective of slurry DM content.

Abatement techniques – slurry injection (Smith et al., 2000b)

Cattle slurry to grassland will be predominantly shallow injection (c. 50 mm) with an abatement efficiency of 70 %.

Pig slurry to arable land will be predominantly deep injection (>100 mm) with an abatement efficiency of 90 %.

Other abatement techniques (trailing shoe and band spreading) are currently used very little in the UK.

Abatement – incorporation

Incorporation within 1 day of application will reduce emission by 30 %. Incorporation within 1 week will reduce emission by 10 % (as used in MANNER, Chambers et al., 1999).

FYM

  • Data from experiments conducted by ADAS (Chambers et al., 1997) and IGER unpublished (WA0618)

FYM / Site / Emission
(% TAN applied) / Duration of experiment (d)
Cattlea / Boxworth / 30 / 18
Pig (old) a / Elveden / 73 / 9
Pig (fresh) a / Elveden / 89 / 9
Cattleb / IGER, North Wyke / 100* / 12
Cattleb / IGER, North Wyke / 100* / 12
Cattleb / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 94 / 12
Cattlec / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 100* / 12
Cattlec / IGER, North Wyke / 94 / 12
Cattlec / IGER, North Wyke / 81 / 12
Cattlec / IGER, North Wyke / 91 / 12
Cattled / IGER, North Wyke / 100* / 12
Cattled / IGER, North Wyke / 89 / 12
Cattlee / Inkberrow / 61 / 7
Cattleg / IGER, North Wyke / 100* / 12
Cattleg / IGER, North Wyke / 100* / 12
Cattleg / ADAS / 100* / 12
Cattleg / ADAS / 100* / 12
Pigc / Gleadthorpe / 100* / 10
Pigc / Gleadthorpe / 6 / 11
Pigc / Gleadthorpe / 40 / 9
Pigc / Gleadthorpe / 53 / 11
Pigc / Gleadthorpe / 33 / 11
Pigc / Drayton / 100* / 11
Pigc / Drayton / 100* / 12
Pigc / Drayton / 100* / 12
Pigc / Drayton / 100* / 12
Pigc / Boxworth / 100* / 12
Pigc / Boxworth / 100* / 12
Pigd / Terrington / 73 / 7
Pigd / Terrington / 8 / 7
Pigd / Terrington / 100 / 7
Pigd / Terrington / 25 / 7
Pigf / SRI / 73 / 7
Pigf / SRI / 75 / 7
Pigg / ADAS / 72 / 12
Pigg / ADAS / 73 / 12
Ducke / Middleton / 56 / 7

aChambers et al. (1997) bIGER project (WA0618) cIGER/ADAS project (WA0633)

dADAS/IGER project (WA0632) eADAS/IGER/SRI project (NT2001) gADAS/IGER project (WA0707)

* In some of the experiments measured loss was >100 % applied TAN. This is thought to be due to problems in analysis of the FYM and methodology is to be investigated.

Average emission factor of 81% of applied TAN.

Abatement – incorporation

Incorporation within 1 day of application will reduce emission by 55 %. Incorporation within 1 week will reduce emission by 25 % (as used in MANNER, Chambers et al., 1999).

Dirty water

  • An assumed DM of 2% gives an emission factor of 15% of applied TAN from the Smith & Chambers (1995) relationship.

Housing

Animal category / Mean EF
g.lu-1d-1 / Values
g.lu-1d-1 / Derived from n values / Source
Cattle slurry-based / 38.2 / 38.5
29.0
43
51
29.4 / 9
3
1 / Demmers et al. (1997)
ADAS/SRI (WA0653)
Phillips et al., in press
IGER (WA0632/AM0110)
Hill (2000)
Cattle straw-based / 25.6 / 13.7
20.6
35
33.2 / 3 / Demmers (1997)
IGER (WA0618),
IGER (WA0632/AM0110)
ADAS/SRI (WA0722)
Calves / 10.6 / 10.6 / Koerkamp et al., 1998

No distinction is made between dairy and beef cattle housing emission factor. Values from IGER (WA0632) and IGER (WA0618) refer to beef cattle; all others are for dairy cattle.

CAMAR data was not used (with exception of calves), as there were doubts about the methodology of measurements from naturally ventilated buildings.

The value for cattle on cubicles from SRI (Phillips et al., in press) excludes measurements made by the external tracer method. The data for the 3rd year of WA0653 was not used; measured emissions were very much lower than for the first 2 years, with several negative values for individual sampling points and dates, although there were no obvious explanatory factors.

Work by Phillips et al. (1998) suggests that summer emissions from dairy cattle housing, where the cattle come in for part of the day for milking, may be of a similar magnitude to winter emissions. An emission factor for summer housing emissions is not explicitly included in the inventory, but housing period is increased to account for the hours each day during the summer when the cattle are in. The emission factor for housing is likely to be higher in summer, because of higher temperatures. However, it is also likely that the floor area from which emission take place will be much reduced, as access to housing may be restricted. Further information on both management practices and emission factors are required to enable a better estimation from this source.

Hard standings

Data from Misselbrook et al., 2001.

Source / site means / mean EF
g NH3-N animal-1 d-1
dairy cow collecting yard / 12.79, 3.98, 4.15, 8.3† / 7.3
dairy cow feeding/loafing yard / 18.11*, 28.50 / 23.3
beef feeding/loafing yard / 16.20, 8.16 / 12.18*

† this value is from the pilot study (Misselbrook et al., 1998)

* omits one suspect high value

Emission factors were expressed per animal rather than per m2 surface area because there were discrepancies in the area per animal allowance between those on the measurement sites and those from survey data (Webb et al., 2001).

Storage

Store / Mean EF
g.m-2d-1 / Values
g.m-2d-1 / Derived from n values / Source
Slurry stores and lagoons without crusts / 4.34 / Assumed to be double that for crusted stores (WA0641)
Crusted slurry stores and lagoons, weeping wall stores / 2.17 / 0.6
1.27, 3.65, 5.7
0.44
1.8
1.7 / 2 / (Phillips et al., in press)
SRI (WA0625)
*IGER (WA0632)
SRI (WA0641)
Hill (2000)
FYM heaps / g.m-2 of initial heap surface area over 30 d
94 / 83
131
110
48
100 / 2
4
3
1 / *IGER (WA0618)
IGER (WA0519)
*IGER (WA0632)
IGER (WA0707)
IGER (WA0716)

Slurry stores are assumed to develop a crust unless they are stirred frequently.

Values derived from measurements made using Ferm tubes have been corrected to account for incomplete recovery of ammonia by Ferm tubes (Phillips et al., 1998). (*IGER values have been divided by 0.7).

Experimental data has shown that almost all of the total emission from stored FYM occurs during the first month after stacking. Therefore, the emission factor is now expressed as loss over the first 30 d storage (or, effectively, loss for heap life-time), and there is no extrapolation for longer storage periods (which may lead to overestimation of emission).

Dirty water

  • TAN content assumed to be 10 % that of slurry. EF therefore taken to be 10 % of that from non-crusted stores - 0.45 g N.m-2d-1.

SHEEP

Grazing

  • Upland sheep based on values from Jarvis et al. (1991) 0N, and grass/clover plots. Mean values for the 2 years were 0.92 and 0.19 g N.animal-1d-1, giving a mean EF of 0.56 g N.animal-1d-1.
  • Lowland sheep based on values from Jarvis et al. (1991) - 420N, clover and grass clover plots giving mean values over 2 yrs of 1.05 and 1.16 g N.animal-1d-1- and on new IGER unpublished data from North Wyke with values of 1.36, 3.95, 2.47, 0.89, 3.11 and 1.78 g N.animal-1d-1. Overall mean gives an EF of 2.0 g N.animal-1d-1.
  • EF for grazing lambs taken to be half the value for sheep, as lamb excretal output is approximately half that of sheep.

Land spreading

  • FYM - value for cattle used.

Housing

  • Based on EF for beef cattle. Ratio for excretal outputs of sheep and beef cattle, multiplied by emission factor for beef cattle housing on straw (converted to per animal per day) gives an emission factor of 4.85 g N.animal-1d-1.

Hard standings

A mean emission factor of 5.0 g NH3-N animal-1 d-1 derived from data from 2 sites (7.20 and 2.82 g NH3-N animal-1 d-1) from Misselbrook et al., 2001.

Storage

  • FYM - value for cattle used.

PIGS

Outdoors

  • Measurements conducted by Williams et al. (2000) give an emission factor for outdoor sows of 25 g N.lu-1d-1. Emission factor for boars assumed to be the same. For fatteners, based on the ratio of excretal outputs multiplied by the emission factor for outdoor sows.

Land spreading

  • Emission factors for slurry and FYM as for cattle.

Housing

Mean EF (gN.lu-1h-1) / Values
(gN.lu-1h-1) / Derived from n values / Source
Dry sows - slats / 0.71 / 0.71 / 2 / Peirson (1995)
- straw / 0.70 / 0.39
0.61
1.09 / 2
4 / Peirson (1995)
Koerkamp et al., 1998
SRI (OC9523)
Farrowing sows - slats / 1.11 / 1.35
0.86 / 3 / Peirson (1995)
Koerkamp et al., 1998
- straw / 1.10 / Estimated from ratio of EF’s for dry sows
Boars -straw / 0.70 / As for dry sows
Fatteners >20kg - slats / 3.16 / 2.92
2.14
4.41
3.02
3.30 / 2
4 / Peirson (1995)
Koerkamp et al., 1998
Demmers (1997)
Peirson (1995)
ADAS (WA0632)
Fatteners >20kg - straw / 2.84 / 2.26
1.18
5.09 / 2
4 / Peirson (1995)
Koerkamp et al., 1998
ADAS (WA0632)
< 20kg - slats / 1.16 / 1.45
0.86 / Peirson (1995)
Koerkamp et al., 1998
< 20kg - straw / 2.84 / As for >20 kg fatteners on straw

Hard standings

An emission factor of 0.32 g NH3-N animal-1 d-1 for pig loading areas (Misselbrook et al., 2001)

Storage

Store / Mean EF
g.m-2d-1 / Values
g.m-2d-1 / Derived from n values / Source
Circular stores, lagoons / 3.16 / 1.34
2.47, 6.2
2.4
1.56
5.0 / 4 / *ADAS (WA0632)
SRI (WA0625)
Phillips et al. (1997)
SRI (WA0708)
Phillips et al., in press
FYM heaps / g.m-2 of initial heap surface area over 30 d
317 / 576
113
262 / 4
1 / SRI (Williams)
*ADAS (WA0632)
ADAS (WA0716)

Values derived from measurements made using Ferm tubes have been corrected to account for incomplete recovery of ammonia by Ferm tubes (Phillips et al., 1998). (*ADAS values have been divided by 0.7).

As for cattle slurry, a common emission factor is used for circular tanks and lagoons.

All emission from FYM heap assumed to occur within first 30 d, regardless of length of storage period.

POULTRY

Outdoors

  • EF for outdoor poultry calculated as 63% of excretal AUN output (i.e. same EF as for land spreading). Note that only a small proportion of poultry droppings is estimated to be voided outside the house.

Land spreading

  • Emission factors from ADAS data:

Manure / Site / Emission (% UAN applied) / Duration of measurement (d)
Broilera / Elveden / 46 / 9
Broilera / Boxworth / 15 / 23
Turkeya / Freckenham / 41 / 30
Layera / Freckenham / 40 / 31
Broilerb / Gleadthorpe / 58 / 10
Broilerb / Gleadthorpe / 32 / 11
Broilerb / Gleadthorpe / 71 / 9
Broilerb / Gleadthorpe / 100* / 11
Broilerb / Gleadthorpe / 100* / 11
Broilerb / Drayton / 70 / 11
Broilerb / Drayton / 57 / 12
Broilerb / Drayton / 34 / 12
Broilerb / Drayton / 33 / 12
Broilerb / Boxworth / 100* / 12
Broilerb / Boxworth / 100* / 12
Layerb / Gleadthorpe / 56 / 10
Layerb / Gleadthorpe / 100* / 11
Layerb / Gleadthorpe / 100* / 9
Layerb / Drayton / 93 / 11
Layerb / Drayton / 62 / 12
Layerb / Drayton / 45 / 12
Layerb / Drayton / 68 / 12
Layerc / Rettendon / 61 / 21
Layerc / Rettendon / 57 / 35
Layerc / Rettendon / 45 / 21
Layerc / Rettendon / 51 / 34
Layerc / Betley / 83 / 21
Layerc / Betley / 49 / 14
Layerc / Betley / 84 / 20
Layerc / Betley / 49 / 21

aChambers et al. (1997) bIGER/ADAS project (WA0633) cADAS/IGER project (NT2001)

* In some of the experiments measured loss was >100 % applied UAN. This is thought to be due to problems in analysis of the poultry manure/litter and methodology is to be investigated.

The average emission factor is 63 % of applied UAN.

Abatement – incorporation (MANNER, Chambers et al., 1999)

Reduction in emission achieved by incorporation:

Incorporation within:1d1 week

Layer manure65%30%

Litter90%75%

Housing

Poultry category / Mean EF
g.lu-1h-1 / Values
g.lu-1h-1 / Derived from n values / Source
Layers- deep-pit (cages, perchery, free-range) / 6.2 / 6.1
7.68
3.29
5.8
8.2 / 3
6 / Wathes et al., 1997 (perchery)
Wathes et al., 1997 (deep-pit)
Peirson (1995) (deep-pit)
ADAS (WA0638) (deep-pit)
ADAS (WA0651 belt-scraped, Bitteswell)
Layers–belt-cleaned (cages) / 2.5 / 1.51
3.3
2.7 / 3
6
7 / Peirson (1995)
ADAS (WA0651 weekly scraping)
ADAS (WA0651 – belt scraped, Bitteswell)
Broilers/all other poultry / 2.8 / 6.84
1.56
3.84
1.65
2.25
1.5
2.8
2.2 / 4
3
4
4
4
2
2 / Wathes et al., 1997
Demmers (1997)
Peirson (1995, turkeys)
Robertson et al., 2002)
Frost et al., 2002
ADAS (WA0651 winter)
ADAS (WA0651 summer)
ADAS (WA0651 drinker study)

Layers in cages – systems where manure is scraped from a collection shelf through a floor slot to a deep-pit are included in the cages deep-pit category. Measurements under WA0651 indicated that a much lower emission factor was obtained for a daily belt-cleaning system as compared with weekly cleaning. However, such frequent cleaning would not be practised on commercial farms and the value is therefore not included here.

Storage

Storage losses can be divided into storage and ‘break-out’ (i.e. when loading to trailer/spreader takes place).

Storage losses

Mean EF / Values / Derived from n values / Source
gN m-2 initial heap s.a. over 30d
Layer manure / 761 / 93
1060
1090
800 / 2
4
4
1 / ADAS (WA0712)
ADAS (WA0651 – bs)
ADAS (WA0651 – dp)
ADAS (WA0651 – bs)
Litter (broilers) / 282 / 140
670
67
250 / 1
4
4
2 / ADAS (WA0712)
ADAS (WA0651 winter)
ADAS (WA0651 summer)
ADAS (WA0651 drinkers)

Break-out losses

Mean EF / Values / Derived from n values / Source
gN m-2 initial heap s.a. over 30d
Layer manure / 25 / 16
71
9
4 / 2
4
1
1 / ADAS (WA0712)
ADAS (WA0651 – bs)
ADAS (WA0651 – dp)
ADAS (WA0651 – bs)
Litter (broilers) / 10 / 26
3
3
7 / ADAS (WA0712)
ADAS (WA0651 winter)
ADAS (WA0651 summer)
ADAS (WA0651 drinkers)

All values corrected to account for Ferm tube recovery factor (divide by 0.7).

DEER

Grazing

  • Sheep grazing (lowland sheep) emission factor used as liveweights similar.

Land spreading

  • Emission factor for cattle FYM used.

Housing

  • Emission factor for sheep housing used.

Storage

  • Emission factor for cattle FYM used.

HORSES

Mean EF of 10.6 kg NH3-N per animal per year used, as for ‘other horses’ in non-agricultural emissions inventory (Sutton et al., 2000).

CONSERVED GRASSLAND & TILLAGE

  • Emission factors (as % N applied) derived from van der Weerden & Jarvis (1997):

FertiliserGrasslandTillage

Ammonium nitrate1.6 %0.8 %

Urea23 %11.5 %

Other1.6 %0.8 %

Sources of other inputs

Animal numbers and weights

Livestock numbers are from the “Digest of Agricultural Census Statistics for UK” (available from DEFRA website).

Livestock weights are from ADAS unpublished data:

Animal / Weight (kg) / Animal / Weight (kg)
Dairy cow (inc. heifers) / 550 / Sow / 200
Dairy heifer in calf / 400 / Farrower / 225
Beef cow (inc. heifers) / Boar / 250
Beef heifer in calf / Fattener >110 kg / 120
Bull / 340 / Fattener 20 – 110 kg / 65
Others > 2 yr / Fattener <20 kg / 12
Others 1-2 yr / Layer / 2.2
Others < 1yr / 140 / Broiler / 0.9
Pullet / 1.0
Breeding hen / 2.0
All other poultry / 4.0

Proportion of sheep in uplands from ADAS (Diane Spence).

Excretal outputs and TAN contents

Manure output values per animal are from Smith and Frost (2000) and Smith et al., (2000). Account is taken of time spent indoors and litter/bedding is included for FYM outputs. For milking dairy cattle, time indoors is increased to account for time in summer spent in buildings or yards for milking operation (equivalent to 3h per day throughout the grazing period).

Proportion of waste produced as slurry or FYM from ADAS Surveys of Animal Manure Practices in the Dairy, Beef, Pig and Poultry Industries (Smith et al., in press).

Slurry TAN contents from Smith and Frost (2000) and Smith et al., (2000a) with 50 % of total N assumed to be ammoniacal-N. TAN contents of FYM assumed to be 10 % of total N for stored FYM and 25 % for FYM spread to land directly from the house, obtained from MAFF (2000), Tables 1 & 2. Poultry AUN contents from MAFF (2000).

Dirty water volume applied to land assumed to be same as volume stored (Nicholson and Brewer, 1994) (for UK increased from E&W volume in same proportion as increase in cattle slurry), and all assumed to be applied to grassland.

Tonnage of poultry litter incinerated obtained directly from 3 power plants (Ayr, Eye and Thetford) using poultry litter as fuel (K Smith, ADAS). The estimate for 2000 was 470,000 t.

Land spreading

Proportion of waste applied to grassland and arable, proportion applied in summer (May-July), proportion applied by injection or irrigated and proportion incorporated within 1d or 1wk of application obtained from ADAS Surveys of Animal Manure Practices in the Dairy, Beef, Pig and Poultry Industries (Smith et al.,2000c, 2001a, 2001b). Proportion of cattle and pig FYM spread to land without storage also obtained from the same source.

Proportion of slurry in each dry matter category from ADAS unpublished (K Smith, B Chambers).

Housing

Proportion of animals in each housing type - cattle from ADAS Surveys of Animal Manure Practices in the Dairy and Beef Industries (1998), pigs from Sheppard (1998) and MLC Pig Yearbook 1993. Proportion of pigs outdoors from Sheppard (1998). Poultry housing and % manure dropped outdoors provided by A Walker (ADAS Gleadthorpe).

Cattle housing periods obtained from ADAS Surveys of Animal Manure Practices in the Dairy and Beef Industries (1998), with housing period of milking dairy cattle extended to account for time in for milking during the summer months. For sheep, ewes indoors for 30 d, lambs not indoors at all. Poultry and pigs assume 100 % occupancy as June census takes a snapshot of animal numbers which will reflect the actual % occupancy.

Storage

Waste storage areas for England and Wales from Nicholson and Brewer (1994). Areas for UK for cattle and pigs calculated by adding areas for Scotland and Northern Ireland from SAC Report (Baines et al., 1997). Area for sheep based on excretal output and storage area for cattle and pigs. Areas are adjusted annually by a multiplier based on holding numbers for each animal category, with 1993 as the base year.

The proportion of cattle stores crusted estimated from ADAS Surveys of Animal Manure Practices in the Dairy and Beef Industries (1998), with stores stirred never or only occasionally assumed to be crusted.

Storage period for poultry manure of 120 d from ADAS Surveys of Animal Manure Practices in the Poultry Industry (1998).

Hard standings

Usage derived from survey conducted under WA0528 (Webb et al., 2001).

Hard standing / Area per animal
(m2) / % animals using hard standing / Usage
(Days per year)
Dairy cow collecting yard / 1.74 / 65 / 365
Dairy cow feeding/loafing yard / 1.70 / 30 / 365
Dairy cow self-feed silage yard / 4.75 / 14 / 180
Beef cattle feeding/loafing yard / 4.32 / 45 / 180
Beef cattle self-feed silage / 4.71 / 9 / 180
Sheep handling area – lowland sheep / 0.92 / 67 / 24
- upland sheep / 0.92 / 67 / 6
Pig loading area / 1.00 / 19 / 4

NB Area per animal not actually used in calculation, but included here for reference.

Fertiliser