Custom Manure Application in Minnesota

Gary Martens, Rick Martens, Don Martens
Martens Manurigation

Jim Hoeft, Mark Hoeft, and Rick Elkins
M Waste Applicators

Steve McCorquodale
McCorquodale Spreading Service

This paper was written by different custom applicators with different spreading equipment. The Martens apply liquid manure using a towed hose applicator. Jim and Mark Hoeft apply liquid manure using towed hose and tanks. One of their spreaders is equipped with Variable Rate Technology (VRT) allowing very precise application rates. Steve McCorquodale is a manure broker and applicator of poultry litter. Gary Martens will give the presentation with an emphasis on applying liquid manure using towed hose equipment.

The existing Minnesota Feedlot Rule requires that all manure applications are within agronomic rates. This rather vague definition is being refined in a revised feedlot rule. Under the existing rule nitrogen is the nutrient of concern, and it will continue to be so in most areas. However, in the revised rule phosphorus will be the nutrient of concern in "Special Protection Areas." Phosphorus will also be a concern in "disposal" situations where large amounts of manure are broadcast without incorporation to promote nitrogen volatilization.

Custom applicators have concerns about what constitutes a spill. For those applying solid manure a common concern is the liability question related to manure stockpiles. Responsible liquid manure applicators are concerned about bidding against thoughtless applicators that reduce costs by applying excessive amounts of manure.

In December 1997, we conducted a survey on commercial manure applicators. Survey postcards were sent out to 46 custom applicators. The respondents were two solid applicators and 18 liquid applicators. There were 17 custom liquid applicators in business from 1995 to 1997. Table 1 shows the amount of liquid manure applied from 1995 to 1997 by these 17 applicators.

Solid manure application differs from liquid manure application in several respects. Liquid manure is more likely applied on the land controlled by the facility generating the manure. Solid manure (especially, poultry litter) is often applied on land not controlled by the facility generating the manure. In fact, solid manure is often stockpiled, and these stockpiles may be from manure generated at different facilities. This leads to some interesting legal questions that have yet to be resolved.

Stockpiles are a major concern for custom applicators, and they should also be a concern for the manure generators supplying manure that ends up in a stockpile. If a stockpile is formed from several different sources, who is responsible if there is a problem?

Because crop producers are paying for the manure, it is hoped that there will be less of a tendency to apply manure in excess of agronomic requirements. However, there may be a temptation to apply excessive rates to build up soil levels of phosphorus. Again this could lead to questions of liability, especially if the manure source is from a stockpile created from several different generators.

Solid manure is often purchased by a crop producer in place of, or to supplement, commercial fertilizer. Custom applicators actively promote manure as a valuable crop nutrient. Some manure generators give manure away for the hauling; others charge a token amount, perhaps two dollars per ton. Custom applicators then resell it to crop farmers at a profit. The service they provide is the hauling and application. Purchasers of manure should be sure the applicator can apply manure evenly and at desired rates. They should also know the manure's nutrient content.

Solid poultry litter is more concentrated in nutrients than many liquid manures and can be hauled longer distances. Hauling within 15 miles is considered optimum, whereas two miles is about the maximum for a towed hose application of liquid manure.

Solid manure can be applied at rates a low as two tons per acre. Three thousand gallons (12.3 tons) would be a low application for liquid manure.

The method of calibration preferred by this applicator is to weigh a semi-truck load of manure at the application site. The known weight of manure is applied on a field of known size. Then the application rate is calculated by dividing the tons applied by the acres. This gives an application rate in tons per acre. Once a spreader is calibrated by this method it is easy to replicate the application rate by recording speed and settings.

Plastic sheets and plywood have not been effective in calibrating solid manure applicators when the manure is discharged at a fair velocity. Manure hitting the plastic or plywood is more likely to bounce off than manure hitting bare soil. This underestimates the application rate. A somewhat more successful method for spot calibration is to use a large divided tray similar to a giant egg carton. The pockets help keep the manure from bouncing off the sheet and give a better estimate of the application rate. Spikes are needed to anchor the divided tray to the ground. I have low confidence in any spot calibration methods.

Unlike liquid fertilizer, we cannot incorporate as we go. We encourage farmers receiving manure to incorporate it quickly. Often they are pushing us as they incorporate the manure we just applied.

I use two, one page contracts, a "Producer Manure Removal Agreement" and a "Manure Marketing Agreement." The following are a few of the provisions from the "Producer Manure Removal" contract.

1. McCorquodale Spreading Service (MSS) will pay producer for manure at -------- dollars per ton, due after every 1,000 tons of removal.
2. MSS will apply manure in accordance with state, county and producer's requirements.
3. MSS will provide to producer any documentation necessary for their permit requirements.
4. MSS will have all equipment disinfected prior to entering onto producer's site.
5. Producer will supply adequate equipment and disinfectant to allow MSS to disinfect all equipment at end of manure removal job.

There are three methods for applying liquid manure: tanks, towed hose, and irrigation. However, with increasing concerns about odor, irrigation is rapidly loosing favor in Minnesota.

An important advantage of tank and towed hose applications over irrigated applications is the ability to incorporate manure into the soil. Incorporation greatly reduces odors, makes more nitrogen available to the following crop, and may eliminate a field operation.

There are a variety of tools available for injection or immediate incorporation. These tools include the familiar knife and sweep injectors. Although knife injectors are frequently mentioned in the literature, few custom applicators use them. Some other types of application and incorporation tools are discs, shallow tillage, minimum tillage, and an AerWay.

Most liquid manure applications are on land controlled by the livestock operator (the manure generator). This contrasts with custom solid applications where the manure (and application) is frequently purchased by crop farmers wishing to replace commercial fertilizer nutrients with manure.

Because liquid manure is typically not sold, there can be situations where the goal is disposal at the lowest cost rather than utilizing it for crop nutrients. Minnesota law requires that manure must not be applied in excess of agronomic rates. Some custom applicators have expressed concern that bidding is not fair unless all applicators apply manure at rates that comply with legal regulations. A goal of the organization, Custom Pumpers, is to educate all applicators so they are familiar with their legal requirements for applying manure within agronomic rates.

One way to accomplish this educational goal is to develop a voluntary or mandatory certification program. For the past year we have been meeting with state officials from the Minnesota Department of Agriculture and the Minnesota Pollution Control Agency to explore possible certification programs.

Originally, our goal was the certification of custom liquid manure applicators. In discussions with state agencies there has been some interest in including others in some type of certification program. Other states, for example, North Carolina, Illinois, and Arkansas require a licensing or certification program for feedlot operators. In Minnesota, we have been talking about a certification program for people applying manure on land, or for people developing manure management plans. This includes all custom manure applicators, county and state staff developing manure management plans, some agricultural consultants, and livestock operators over a certain size (to be determined).

If the state does not require mandatory certification, it seems likely the custom applicators will at least develop a voluntary certification program. It is our goal to have a mandatory certification program for the custom applicators.

We use towed hose and tanks, and each system has its advantages and limitations. For jobs with at least 500,000 gallons, towed hoses are often more efficient than tanks. However, smaller operations often favor tanks because there is less set up required. Two miles is about the maximum application distance for a towed hose; longer distance hauling is possible with a tank.

This past summer we have been testing a tank unit with Variable Rate Technology (VRT) from AgChem equipment of Minnetonka, MN. This is the first (and only) tank with this technology used for commercial manure application.

There are several advantages for this equipment. This equipment makes it easier to apply within agronomic rates. We can easily apply at lower rates (3,000 to 4,000 gallons per acre). By comparing our meters with the calculated rates (based on total amount of manure and acres applied to) we found the accuracy was within one to five percent on most jobs.

Applying variable rates of manure to different areas of the field based on soil grid maps is another big advantage. We charge extra for this service and our customers feel it is worth it. On average, we cover 30 acres with VRT compared to 20 acres with conventional application using the same amount of manure.

Minimum application rates vary depending on the equipment used. Our VRT tank has a minimum application rate of about 3,000 gallons per acre. Our pressure vacuum system tanks have a minimum rate of 5,500 gallons per acre. Towed hoses have a minimum application rate of about 8,000 to 9,000 gallons per acre.

Presently we are using an AerWay applicator. The AerWay has a roller with spikes that opens the soil. When the AerWay Way travels perpendicular to the tractor there is little soil disturbance making it suitable for manure application over alfalfa or pastures. The angle can be adjusted away from perpendicular (5 positions, from 0^o to 10^o), making the AerWay more aggressive in tilling as the angle increases.

Keeping comprehensive records has been adopted as a voluntary Best Management Practice (BMP) and will likely be required in the revised feedlot rule. We use a digital camera in the field to record fields (from maps) where we apply manure. This image is stored in the computer along with the date, application rate, and manure analysis to develop a record keeping system. Printouts of these maps are given to our customers after the manure is applied.

We analyze manure for nitrogen using a Manure Sampling Kit from Farm Home Offices of Iowa. It only costs about $1 for the materials to run the test and can be done during slack periods so there is no additional labor cost. This makes it possible to analyze manure several times during pumpout and adjust the application rate accordingly.

We use a Krohne Magnetic Inductive Flowmeter to measure the application rate. A crucial feature of these meters is that the viscosity of the fluid does not affect the measurement. This means we get accurate measurements whether we are pumping a second stage lagoon or an underbarn pit.

Sand bedding is the bane of custom applicators. Sand is hard on pumps, agitators, hoses, and bearings. It clogs hoses so badly they have to be cut apart. Many of us refuse to work with operations using sand bedding.

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