Exercise 6. Determining Manure Application Rates
for Your Farm

(adapted from Olson and McKenzie, 1998)
In this exercise, use the amount of manure produced on your operation, as well as soil and manure tests if possible, to determine manure application rates. Application rates will be determined for both nitrogen and phosphorus. If soil and manure tests are not available, use the Alberta Code of Practice (AAFRDa) values for manure analysis and Data Sheet 4 for nitrogen and phosphate recommendations. Data Sheet # 4. General fertilizer recommendations for Alberta (Rate in pounds of nutrient per acre) a (AAFRD 1995b).
Crop Previous
crop
Brownb Dark Brownb Thin Black Black and Grey Wooded
nitrogen
(N)
phosphate
(P2O5)
nitrogen
(N)
phosphate
(P2O5)
nitrogen
(N)
phosphate
(P2O5)
nitrogen
(N)
phosphate
(P2O5)
potassium
(K2O)
sulphur
(S)
Spring Wheat fallow 5 - 20 10 - 20 5 - 20 15 - 35 5 - 25 15 - 35 5 - 35 15 - 40

stubble 20 - 50 0 - 15 25 - 60 0 - 25 35 - 65 10 - 35 30 - 80 15 - 40

Malting barley fallow - - 5 - 15 15 - 35 5 - 25 15 - 35 5 - 35 15 - 40

stubble - - 25 - 50 0 - 25 35 - 65 10 - 35 30 - 80 15 - 40

Oats and
feed barley
fallow 5 - 20 10 - 20 5 - 15 15 - 35 5 - 30 15 - 35 5 - 40 15 - 40

stubble 20 - 55 0 - 15 35 - 65 0 - 25 35 - 80 15 - 35 40 - 100 15 - 45

Fall rye fallow - - 25 - 35 20 - 30 25 - 35 20 - 35 5 - 20 20 - 35

stubble - - 30 - 55 15 - 25 30 - 60 15 - 30 35 - 70 20 - 35

Winter wheat fallow 20 - 30 10 - 25 25 - 35 20 - 40 25 - 45 25 - 45 -


stubble 25 - 55 10 - 25 30 - 65 15 - 30 40 - 80 20 - 40 -


Flax fallow - - 5 - 10 10 - 20 5 - 10 15 - 20 5 - 10 15 - 20

stubble - - 20 - 30 0 - 15 20 - 45 0 - 20 20 - 45 15 - 20

Canola and
mustard
fallow 5 - 15 10 - 20 5 - 30 15 - 20 5 - 35 15 - 25 5 - 45 15 - 35 - 0 - 10
stubble 20 - 55 10 - 15 35 - 70 15 - 20 30 - 80 15 - 25 40 - 100 15 - 35 - 0 - 20
Grass for seed - - 30 - 60 0 - 15 30 - 70 0 - 30 45 - 90 0 - 40 - 0 - 10
For forage (with <20% legume) - - 40 - 90* 0 - 15 60 - 110* 0 - 30 60 - 120 0 - 40 - 0 - 10
Grass - Legume 20-40% legume - - 30 - 65 0 - 20 40 - 80 0 - 35 45 - 90 0 - 35 - 0 - 30
40-60% Legume - - 10 - 30 0 - 35 10 - 30 0 - 45 10 - 30 0 - 50 - 0 - 30
Legume > than 60% - - - - - - 0 - 10 0 - 60 - 0 - 30

- - 0 - 10 0 - 35 0 - 10 0 - 50



Potatoes fallow - - - - - - 25 - 50 45 - 90 30 - 60 0
stubble - - - - - - 70 - 110 55 - 110 50 - 100 0

a Residual response to the higher rates may persist for two years, particularly when the year of application is dry and production is low. Therefore annual application may not always be necessary.
b See comments regarding soil moisture reserves and their importance in determining crop rotations and choosing fertilizer rates under major Soil Group and Choosing the right kind of fertilizer.

Brown soils - occur in semi-arid short grass prairie region, annual precipitation about 30cm. Moisture limits crop production the most. Stubble cropping not recommended unless >75 cm of moist soil on medium textured(loam) soils or 55cm on fine textured(clay) soils.

Dark Brown soils - occur in prairie region, annual average precipitation about 35cm. Stubble cropping not not recommended unless >68cm of moist soil on medium textured soils, 50cm on fine textured soils

Thin Black soils - occur as a strip within the Black zone. Rainfall quite variable in this area. Increased production can be realized from adjusting crop rotations and fertilizer rates to match soil moisture reserves.

Black and Grey Wooded - little need for fallowing to store soil moisture. Higher rates of fertilizer recommended in Data Sheet #4 are suggested when previous experience has shown a good response to fertilizer and other management practices are geared to high yields.

Nitrogen fertilizer requirements cover a very wide range of application rates. For example, crops grown on fallow will often require little or no additional nitrogen, whereas non-legume crops grown on stubble land can give profitable returns to application rates of 100 lb/acre or more of nitrogen (N). The yield potential of crops is a major factor affecting nitrogen fertilizer requirements.

 

Worksheets

Land needed to maintain a nitrogen balance

A
Manure (tons)
B
Manure application rate (tons/acre)
A / B
Land required (acres) to maintain a nitrogen balance

   

Land needed to maintain a phosphorus balance

A
Manure (tons)
B
Manure application rate (tons/acre)
A / B
Land required (acres) to maintain a phosphorous balance

   

 

Application based on Nitrogen A
Acres
B*
Recommended N fertilizer rate (lbs/acre)
C**
Manure Crop N
content (lbs/ton)
D= B / C
Manure Application
rate (tons/acre)
E= A X D
Total Manure Applied (tons)
Manure remaining starting from 360 tons***
Field Name and next crop










































Application based on Phosphorus F
Acres
G*
Recommended P2O5 fertilizer rate (lbs/acre)
H**
Manure Crop P2O5 content (lbs/ton)
I= G / H
Manure application
rate (tons/acre)
J= F x I
Total Manure
Applied (tons)
Manure remaining starting from 360 tons***
Field name and next crop
























































* Based on soil test recommendations, or if not available, use Data Sheet 4
** From data sheet 3
*** From exercise 1a