Plant-Availability Coefficients

Some of the nutrients in manures are primarily in organic forms and must undergo microbial mineralization before those nutrients are available to plants. Once nutrients are in a plant-available form, some nutrients can potentially be lost in gaseous forms. For example, nitrogen is susceptible to gaseous losses due to volatilization of ammonia. As a result, the availability of nitrogen is dependent on the mineralization potential of the manure as well as the application method of the manure. Subsurface placement of manure tends to reduce volatile losses whereas surface applications tend to increase volatile losses.

Neither phosphorus nor potassium are subject to volatile losses, meaning manure application method has minimal effect on the availability of these two nutrients. In fact, current data reviewed by the NC Interagency Nutrient Management Committee shows that phosphorus and potassium availability from manure sources is no different than the availability from commercial-inorganic fertilizer sources. For this reason, effective 1 July 2013, the availability of phosphorus and potassium in manure sources will be assumed to be 100% (i.e., plant-availability coefficient of 1.0).

 

Plant Availability of nitrogen (N), phosphorus (P) and potassium (K) from manure nutrient sources.
N
P2O5
K2O
Production
System
NCDA&CS
Waste Code
Broadcast
or Irrigated
Incorporated
or Injected
Broadcast
or Irrigated
Incorporated
or Injected
Broadcast
or Irrigated
Incorporated
or Injected
Anaerobic Lagoon Liquids
Anaerobic Lagoon Liquid
– Swine
ALS
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Liquid
– Swine Farrow to Wean
ALF
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Liquid
– Poultry
ALP
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Liquid
– Other
ALO
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Sludges
Anaerobic Lagoon Sludge
– Swine
ASS
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Sludge
– Poultry
ASP
0.5
0.6
1.0
1.0
1.0
1.0
Anaerobic Lagoon Sludge
– Other
ASO
0.5
0.6
1.0
1.0
1.0
1.0
Slurries
Slurry
– Beef
LSB
0.4
0.6
1.0
1.0
1.0
1.0
Slurry
– Dairy
LSD
0.4
0.6
1.0
1.0
1.0
1.0
Slurry
– Swine
LSS
0.4
0.6
1.0
1.0
1.0
1.0
Slurry
– Other
LSO
0.4
0.6
1.0
1.0
1.0
1.0
Scraped or Stockpiled Manure
Scraped or Stockpiled
– Beef
SSB
0.4
0.6
1.0
1.0
1.0
1.0
Scraped or Stockpiled
– Dairy
SSD
0.4
0.6
1.0
1.0
1.0
1.0
Scraped or Stockpiled
– Horse
SSH
0.4
0.6
1.0
1.0
1.0
1.0
Scraped or Stockpiled
– Swine
SSS
0.4
0.6
1.0
1.0
1.0
1.0
Scraped or Stockpiled
– Other
SSO
0.4
0.6
1.0
1.0
1.0
1.0
Poultry Litters
Poultry Litter
– Breeders
HBB
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Broilers
HLB
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Broiler Pullets
HBP
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Layers
HLL
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Layer Pullets
HLP
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Turkeys
HLT
0.5
0.6
1.0
1.0
1.0
1.0
Poultry Litter
– Other
HLO
0.5
0.6
1.0
1.0
1.0
1.0