Tone Ag Consulting Ltd.

With higher fertilizer prices, a couple people asked us about charging for the manure from their barns.  How do you determine what manure is worth?

Using the numbers from the Farm Practices Guidelines (FPG), application by injection, and the target nutrient rate of 100 lbs. N/acre, here are some figures for Farrow, Nursery, and Finisher barns.  These are rough, hand-wavy figures but can serve to give some idea of the value of manure.

Value of Nitrogen in Manure

The current price of N is about $0.53/lb.  If you are applying manure at about 100 lbs. N/acre, that is worth about $53.00 /acre

• Farrow barns have an average NH4-N of 16 lbs./1000 gal.
• Nursery barns have an average NH4-N of 20 lbs./1000 gal.
• Finisher barns have an average NH4-N of 24 lbs./1000 gal. 

For liquid hog manure, Organic N is usually a fairly small part of the N that will be available to the crop, so I have left it out of these calculations to keep things simple.  For solid manure, organic N is a much larger consideration. 

Target N is 100 lbs./acre, so you would inject:

• 6,250 gal/acre of manure from the Farrow barn
• 5,000 gal/acre of manure from the Nursery barn
• 4,200 gal/acre from the Finisher barn.

Value of Phosphate in Manure

• Farrow barns have an average P2O5 of 15 lbs./1000 gal.
• Nursery barns have an average P2O5 of 11 lbs./1000 gal.
• Finisher barns have an average P2O5 of 15 lbs./1000 gal. 

Phosphate (P2O5) is currently worth about $0.72/lb.

• 6,250 gal/acre * 15 lbs./1000 gal. * $0.72 / lb. = $67.50 / acre for a Farrow barn
• 5,000 gal/acre * 11 lbs./1000 gal. * $0.72 / lb. = $39.60 / acre for a Nursery barn
• 4,200 gal/acre * 15 lbs./1000 gal. * $0.72 / lb. = $45.36 / acre for a Finisher barn

Value of Potash in Manure

• Farrow barns have an average K2Oof 15 lbs./1000 gal.
• Nursery barns have an average K2O of 11 lbs./1000 gal.
• Finisher barns have an average K2O of 15 lbs./1000 gal. 

Potash(K2O) is currently worth about $0.58/lb.

• 6,250 gal/acre * 13 lbs./1000 gal. * $0.58 / lb. = $47.13 / acre for a Farrow barn
• 5,000 gal/acre * 19 lbs./1000 gal. * $0.58 / lb. = $55.10 / acre for a Nursery barn
• 4,200 gal/acre * 18 lbs./1000 gal. * $0.58 / lb. = $43.85 / acre for a Finisher barn

Value of Micronutrients and Other Manure Benefits

It’s difficult to say what micronutrients will be included in manure.  There are a variety of micronutrients supplied in manure, but which micronutrients will be supplied and at what levels depends on the types of animals and their diets.  One proven benefit of manure application is an increase in soil quality, particularly soil organic matter.  I have opted not to include these in the value of manure due to their variability.

Naive Calculation for the Value of Manure

Using only the Nitrogen, Phosphate, and Potash values, here is the value per acre of manure

• Manure from Farrow barns is worth about $167.67 / acre
• Manure from Nursery barns is worth about $147.70 / acre
• Manure from Finisher barns is worth about $142.21 / acre

This is a naive calculation because it assumes that all nutrients supplied are exactly what is needed by the crop.  Based on the examples above, you’re going to be getting 55-95 lbs. P2O5 / acre.  There are very few crops that can use that much P2O5, so the extra is used to build up the soil for next year.  It’s a similar situation for the K2O.  It’s not likely that a landowner will be willing to pay for these excess nutrients. 

Charging for Manure

The problem with charging for manure is that manure is quite variable.  There will be more or less nutrients at different points in the manure application, so some areas of the field may end up over or under fertilized.  At this point I know of no economical way of guaranteeing a consistent application of nutrients from manure.  There may be liability issues if you promise a farmer a precise amount of nutrients, so often operators end up undercharging and over-delivering.

Here are some of the common ways of charging a landowner for manure in Manitoba:

• Charge based on the value of the nitrogen that is applied to the land.     A landowner might pay 25-100% of the value of the equivalent amount of commercial nitrogen.  Estimate $13-$53 / acre for 100 lbs of N.
• Flat payments of $10-20 / acre
• Paying for application costs $42-$62 / acre based on fees of $0.01 / gallon
• Landowner favorite of getting the manure for free! $0

These are all well below the naive calculation’s values but it still shows that it’s worth it for operators to talk to landowners about what they would be willing to pay to have manure applied to their land.  

If you want to do your own calculations for the value of manure, see Bob Koehler and Bill Lazarus’s spreadsheet for Determining Manure Value (found via Manure Manager January/February 2009)

EDIT: Corrected typo.