University of Minnesota Extension
www.extension.umn.edu
612-624-1222


Extension > Local Extension Offices > Benton > County Agriculture Educator > Articles > Manure Nutrients Count on Next Year’s Crop Budget

Manure Nutrients Count on Next Year’s Crop Budget

University of Minnesota Extension, Stearns County News
October 7, 2015         
           
Source:  Dan Martens, Extension Educator
University of Minnesota Extension
Stearns, Benton & Morrison Counties

 

Manure Nutrients Count on Next Year’s Crop Budget
By Dan Martens, University of Minnesota Extension

FOLEY, Minn. (10/02/2015) —Manure application follows harvest; and manure nutrients can count a lot toward 2016 crop production budgets and potential for profits. Several practices and factors play into how well we do with capturing the nutrient value from manure and turning it into crop profits.

Let’s look at just nitrogen (N) for an average sample of liquid dairy manure that has 24 pounds of N per 1000 gallons. Let’s compare a manure application for nitrogen to applying urea where the nitrogen is worth $0.50 per pound. If the manure is applied and incorporated within 12 hours, 65% of this nitrogen could be available to next year’s crop. Then 65% x 24 pounds provides 15.6 pounds of N. That’s $7.80 of nitrogen value per 1000 gallons manure (15.6 lbs. x $0.50). If we use U of M guidelines that shows merit to applying 150 pounds N per acre for a particular soil type, we might apply 9,600 gallons of manure per acre (150 divided by 15.6 pounds N available per 1,000 gallons). The total value of the nitrogen available next year on a per acre basis would be $74.88.

We might have 20% of the nitrogen available the next year too. That would be another 30 pounds N per acre, theoretically worth $15, bringing the total to about $90 per acre ($75 + $15).

The % N available to the next crop varies with how and how soon the manure is incorporated. Here are some numbers just for first year available nitrogen and per acre value from 9,600 gallons on average liquid dairy manure.

Broadcast and Incorporated
     0 to 1/2 Day: 65%, $75
     1/2 to 4 Days: 45%, $52

Incorporated more than
    4 days later:    25%, $29
    Sweep Injection: 60%, $69
    Knife Injection:  45%, $52

Obviously this varies with equipment used, soil and weather conditions, and time of year. I’d expect that a knife application with disks that kicked a good amount of soil over the knife slot might do better. One suggestion is to apply manure, like we recommend for anhydrous ammonia in other parts of the state in the fall – after soil temperature is consistently below 50 degrees. This minimizes conversion of nitrogen to nitrates that are vulnerable to leaching with heavy rain events that could occur yet in the fall or following spring. Waiting that long may not be practical in the context of all the work farmers and custom manure applicators have to do.

Here are a few of the other things that might be considered:

  • Hauling Cost. It often costs more to haul and spread manure nutrients than to spread the same nutrients with commercial fertilizer. It might cost $0.01 per gallon of liquid manure. Then it would cost $96 to apply 9600 gallons of liquid dairy manure. There may be nutrients beyond the nitrogen that are needed that more than cover this cost. Livestock farms have to move manure. Another way to look at the economics might be to recover as much of the hauling cost as possible. 
  • Phosphorus Management. For most manure and soil situations, when manure is applied to meet the nitrogen need of the crop, we are applying more phosphorus than that crop needs. When soil test phosphorus levels get beyond certain levels for land within certain proximity to water channels, rules require manure applications to be made based on phosphorus crop needs. We may be applying more potassium than the crop needs also. The most effective way to manage phosphorus levels is for livestock farmers to share manure with crop farmers who don’t have livestock.
  • The Manure Bonus. Many farmers figure they get a 5 to 10% yield advantage by applying manure nutrients compared to commercial fertilizer. This might be due to other nutrients in the manure and manure’s benefit to soil biology and organic matter. Getting this bonus depends on effective manure nutrient management practices; and can be affected by weather and other factors also.


It is also important to consider Good Neighbor practices with manure applications. Neighbors do well to talk with each other about things. Consider wind direction when you can. Non-farm neighbors can remember other advantages they considered in moving to the country where agriculture is the primary land use.

For crop and livestock farmers looking at manure value together, search for “Minnesota Extension What’s Manure Worth” for a worksheet that can be helpful in looking at the value of manure based on many of the factors considered here. Remember the nutrients that have value are the nutrients that are available and needed for the land where it is applied, based on the crop grown.

U of M Extension, Soil and Water Conservation Districts, Crop Consultants, and Agronomy Advisors have resources for helping farmers look for better ways to make the best use of manure nutrients, while trying to make a living and taking care of soil and water resources the best you can. You see the benefits first on your own farm.

As with other fall work, make SAFETY a priority.

 

Contacts

Daniel Martens
Extension Educator, Ag Production Systems
(320) 968-5077
marte011@umn.edu
  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy