May UPDATE to Manure Spreading Advisory #2 2014: South Coast Region

Do you know the nitrogen (N) fertilizer value of manure?

  • Example: A farmer broadcasts 45,000 L per hectare (4,000 imperial gallons per acre) of liquid manure in the spring. The N fertilizer value of this manure, in the year of application, depends largely on the total N and ammonium-N contents of the manure:

(% total N, % ammonium-N)

Equivalent N amount (kg/ha)

Value at $1.25/kg N

Value at $1.50/kg N

Dairy, liquid (0.13% N, 0.07% NH4-N)




Dairy, slurry (0.28% N, 0.15% NH4-N)




Hog, liquid (0.35% N, 0.26% NH4-N)




Your manure (?)





(% total N, % ammonium-N)

Equivalent N amount (lb/ac)

Value at $0.57/lb N

Value at $0.68/lb N

Dairy, liquid (0.13% N, 0.07% NH4-N)




Dairy, slurry (0.28% N, 0.15% NH4-N)




Hog, liquid (0.35% N, 0.26% NH4-N)




Your manure (?)




See the next page for the assumptions about N losses and availability.

  •  Reliable estimates come from analyses of your manure (see the April 1 Update).

Producers are responsible for decisions regarding manure spreading. Legislation gives no specific dates for manure spreading but it does not allow for manure to be spread in a manner that causes pollution. This Update is produced by government, in partnership with industry, to provide guidance to farmers regarding the Agricultural Waste Control Regulation and the ENVIRONMENTAL MANAGEMENT ACT. If a discrepancy arises between this document and the legislation, the legislation takes precedence. Following this advisory does not relieve anyone from their obligations under the LEGISLATION. The Province of British Columbia does not guarantee the accuracy or completeness of the information referenced here from legislation, and in no event is the Province liable or responsible for damages of any kind arising out of its use.

For further information, please contact: BC Ministry of Agriculture
David Poon, P.Ag 604-556-3098
Geoff Hughes-Games, P.Ag 604-556-3102

For questions of a regulatory nature: BC Ministry of Environment
George Rushworth, P.Ag 604-582-5211

Assumptions used to estimate equivalent fertilizer nitrogen (N) amounts (see above)

  • Application of manure at 45,000 L per hectare (4,000 imperial gallons per acre)
  • Total N and ammonium (NH4) N contents on an as-received basis o Dairy, liquid (98% water): 0.13% N; 0.07% NH4-N o Dairy, slurry (94% water): 0.28% N; 0.15% NH4-N o Hog (96% water): 0.35% N; 0.26% NH4-N o Actual values vary from farm to farm
  • Ammonia (NH3) loss: percentage of NH4 lost to the air was estimated using the Ammonia Loss calculator ( with the following assumptions:: o Broadcast by splashplate with no incorporation, at an air temperature of 10°C and no wind o Dairy, liquid (98% water): 43% loss of NH4 o Dairy, slurry (94% water): 62% loss of NH4 o Hog (96% water): 49% loss of NH4
  • Mineralization: 25% of the organic N transforms into plant-available form in the year of application. In manure, organic N is Total N minus NH4-N. Additional notes
  • The above excludes the N value of manure in the 2nd and 3rd year after manure application. The N is temporarily stored in soil organic N and released in the 2nd and 3rd years.
  • The value of phosphorus (P) or potassium (K) in manure depends on P or K levels in the receiving soil: the greater the soil test P or K, the less is the value of the manure P or K in general.
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