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N chain calculations

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Danish/Dansk

N CHAIN CALCULATIONS

The amount of N2O emissions related to a given amount of fertilizer N is determined by the entire N chain from the original fertilizer use to the final uses and losses.

This tool deals with N amounts and N2O emissions from a different perspective, following the N from a given source instead of calculating total amounts from different sources.

Therefore it enables detailed calculations of N uptake efficiencies and N2O emissions related to specific crops, crop rotations, and uses such as fodder, food, and fuel; in connexion with fodder, the N is followed through the animals to food and to manure and further through the following crop(s).

Each calculation begins with a specific amount of fertilizer N and follows it through a specific first crop to specific uses and losses, and it follows the recycled N, if any, through specific subsequent crops to specific uses and losses, until the entire amount of N has left the agricultural circulation.

The comprehensive N chain calculations spreadsheet consists of five Sheets; you may open/close the following summaries to see their contents, structure, purpose, and bases:

Sheet A: Introductory part
  • General information;
  • List of contents for the whole spreadsheet;
  • Detailed explanatory notes for the whole spreadsheet;
  • Verifiable sources for the whole spreadsheet.
Sheet B: Danish crop values
  • Basic properties of a number of crops, including precrop values, N contents, and digestibility;
  • Basic yields and N uptake efficiencies;
  • Recalculated yields and N uptake efficiencies when precrop values are incorporated;
  • Recalculated yields and N uptake efficiencies when straw is used;
  • Total yields and N uptake efficiencies when plant residues are included.

All yields and N uptake efficiencies are calculated for each of the Danish soil types and as weighed averages for all Danish soil types.

All values are based upon norm figures/statistics.

Sheet C: N chain calculations, Danish average values

Page C1: Basic values:

  • Crop values from Sheet B for normal agricultural use of crops;
  • Corresponding crop values for other crop parts in connexion with liquid biofuels;
  • Properties of fertilizer/manures, including volatilization and N efficiencies, depending on manure handling;
  • Fodder to food efficiencies for a number of domestic animals;
  • N2O emission values according to the 1996 and 2006 IPCC Guidelines.

All values are based upon norm figures/Danish National Inventories/IPCC Guidelines.

Page C2: Calculations:

  • Heading describing the first two years of crop rotation;
  • N2O emission values:
    • N2O-N to N in first crop;
    • N2O-N to N in final use;
    • N2O-N to N in original fertilizer.
  • Final N amounts used and lost;
  • Crop rotation, uses, and losses, all based upon user options;
  • Possible additions of non IPCC Guidelines emission values and total N2O emisions.
Sheet D: N chain calculations, with optional basic values

Page D1: Basic values:

  • Crop values, some from Sheet B, N uptake efficiencies and fertilizer amounts optionally chosen by the user;
  • Properties of fertilizer/manures, including volatilization and N efficiencies, depending on manure handling;
  • Fodder to food efficiencies for a number of domestic animals, optionally chosen by the user;
  • N2O emission values according to the 1996 and 2006 IPCC Guidelines.

All values are based upon user values/norm figures/Danish National Inventories/IPCC Guidelines.

Page D2: Calculations:

  • Heading describing the first two years of crop rotation;
  • N2O emission values:
    • N2O-N to N in first crop;
    • N2O-N to N in final use;
    • N2O-N to N in original fertilizer.
  • Final N amounts used and lost;
  • Crop rotation, uses, and losses, all based upon user options;
  • Possible additions of non IPCC Guidelines emission values and total N2O emisions.
Sheet E: Total Danish N amounts
  • Total N amounts in Danish fodder from different sources;
  • Shares of total fodder N amounts from specific sources, especially cereals and rapeseed fodder cakes;
  • Total N amounts in synthetic N fertilizer and animal manure applied to Danish fields.

All values are based upon statistics.

Get the current version of the N chain calculations spreadsheet as OpenOffice (ODS) and use it, and/or get the individual Sheets as PDF and read them:
Sheet A
Sheet B
Sheet C
Sheet D
Sheet E

The N chain calculations form an important part of the basis of the Disproof of the ACP biofuel paper, performed with extended Sheets C and D. Get the extended versions here.

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