Denmark's National Inventory Report 2005 - Submitted under the ...

6.5 NMVOC emission
Less than 1% of the NMVOC emission origins from the agricultural sector, which in the Danish
emission inventory includes emission from arable land crops and grassland. Activity data is given
from Statistics Denmark. The emission factor for arable land crops (393 g NMVOC/ha) and grassland
(2120 g NMVOC/ha) (Fenhann and Kilde 1994, (Priemé and Christensen 1991).
Table 6.27 NMVOC emission from agricultural soils 1990 - 2003
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Arable crops (1000 ha) 2 336 2 341 2 340 2 314 2 303 2 322 2 307 2 293 2 254 2 044 2 064 2 075 2 138 2 125
Grassland (1000 ha) 498 478 458 473 472 466 462 463 484 647 446 450 403 405
NMVOC emission (Gg) 1.90 1.89 1.88 1.91 2.18 1.76 1.77 1.69 1.69 1.65 1.68 1.69 1.65 1.64
6.6 Uncertainties
Table 6.25 shows the estimated uncertainties for some of the emission sources based on expert
judgement (Olesen et al. 2001, Gyldenkærne, pers. comm., 2004). The uncertainties for the number
of animals and hectares grown with different crops are very small. The Danish Normative System
for animal excretions is based on data from the Danish Agricultural Advisory Centre (DAAC).
DAAC is the central office for all Danish agricultural advisory services. DAAC does a lot of research
as well as collecting efficacy reports from the Danish farmers for dairy production, meat
production, pig production etc. to optimise the productivity in Danish agriculture. In total feeding
plans from 15-18% of the Danish dairy production, 25-30% of the pig production, 80-90% of the
poultry production and approximately 100% of the fur production are collected. These basic feeding
plans are used to develop the Danish Normative System. The Normative System has been updated
annually from 2000. For dairy cows approximately 800 feeding plans are used to develop the
norm figures. The normative figures (Poulsen et al. 2001) are the arithmetic mean. Based on the
feeding plans the standard deviation in N-excretion rates between farms can be estimated to ±20%
for all animal types (Hanne D. Poulsen, DIAS, pers. comm). However, due to the large number of
farms included in the norm figures the arithmetic mean can be assumed as a very good estimate
with a low uncertainty. All cattle, sheep and goats have their own ID-number (ear tags) and hence
the uncertainty in these number is almost absent. Statistics Denmark has estimated the uncertainty
in the number of pigs to less than 1%. The combined effect of low uncertainty in actual animal
numbers, feed consumption and excretion rates give a very low uncertainty in the activity data.
The major uncertainty is therefore related to the emission factors.
In general the Tier1 uncertainty is used in the emission factors. A normal distribution is assumed.
In the future Monte Carlo simulations will be made to increase the outcome from the uncertainty
analysis.
The highest uncertainty is connected with manure management and nitrous oxide from leaching.
The applied emission factor for CH 4 from manure management is 10%. This figure may be underestimated
and the uncertainty is therefore increased to 100% until further investigations reveal
new data. Research on this topic will be made in Denmark in the next 2-3 years.
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