ESTIMATION OF N2O EMISSIONS FROM CROP RESIDUES

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ESTIMATION OF N2O EMISSIONS FROM CROP RESIDUES

• USING IPCC TIER 1a AND TIER 1b METHODS
• Adrian Leip
• Joint Research Centre

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IPCC METHODOLOGY FOR DIRECT EMISSIONS OF N2O FROM
AGRICULTURAL SOILS

• IPCC APPROACH TIER 1a

fraction of total aboveground crop biomass that
is removed from the field as crop. (IPCC 2000)
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• IPCC APPROACH TIER 1b

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Table 4.16 - IPCC 2001
If a default residue nitrogen content is needed
for a crop type for which a value is not provided
in Table 4.16, the non-crop specific default
values for N-fixing and Non-N-fixing crops that
are listed in Table 4-19 of the Reference Manual
of the IPCC Guidelines can be used (0.03 and
0.015 kg N/kg dry matter, respectively). (IPCC,
2000)
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The IPCC Guidelines present a default value for
FracR of 0.45 that is not consistent with the
default value presented for aboveground crop
residue and product. If FracR 0.45, then 55 of
the residue plus crop product mass equals
residue. However, if residue plus crop product
mass equals 2 times the crop product, then 50 of
the residue plus crop product mass equals
residue. (IPCC 2000, p. 4.59)
?

• Unit of factor 2 kg dry total biomass / kg dry
  biomass in crop product
• Unit of FracR kg N in crop residue / kg N
  dry total biomass

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Nitrogen fractions kg N (kg dry matter)-1
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EMISSIONS OF N2O FROM CROP RESIDUESGg N2O

• The German values are calculated with national
  data expressed in kg N/ha of crop produced, and
  therefore not directly comparable with the
  other values
• Spain uses a methodology developed by allocating
  the total amount of nitrogen extracted by the
  plants (calculated estimated in particular
  for the plant fractions burnt or buried into the
  soil (Ferreiro, 2003)

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RECOMMENDATIONS (i)

• The default values presented in Tier 1a and Tier
  1b methods yield large discrepancies in the
  emission estimates
• Default values for the nitrogen fraction in crop
  residues need to be streamlined.

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RECOMMENDATIONS (ii)

• The list of default parameter for calculating N2O
  emissions from crop residues does not reflect the
  complete cropping pattern in many countries.
• (a) MS are encouraged to deliver a list of
  important crops for which default values should
  be proposed
• (b) The guidelines should expand the list of
  default parameter for N2O emissions from crop
  residues.

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RECOMMENDATIONS (iii)

• National parameters are important for assuring
  high quality of the estimate for N2O emissions
  from crop residues. They are usually reported in
  the National Inventory Reports.

A link / the use of background Table4.F would
ensure a more transparent reporting of N2O
emissions from crop residues.
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parenthesis Countries which have reported
burning of crop residues
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RECOMMENDATIONS (iv)

• Intercrops are common in certain regions of
  Europe and affect largely timing and rate of
  nitrogen input.
• The use of intercrops should be reflected in the
  guidelines.

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• THANK YOU FOR YOUR ATTENTION !