IMMAG Updates

May 2016

Welcome to the monthly update for the Iowa Manure Management Action Group (IMMAG) Web site. This update is provided as a service to inform you about changes made to the IMMAG Web Page or items of interest dealing with manure management and air quality from animal feeding operations. If you wish to subscribe to this mailing please click here. You may also view this update with direct links on the CURRENT NEWS site on IMMAG.

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Safety Focus - Hydrogen Sulfide:
Hydrogen sulfide gas continues to be a serious issue in and around barns, especially when agitating or pumping the manure. As the amount of distiller’s grains in feed rations has increased, so has the amount of sulfur excreted by the animal. Over the past ten years, sulfur concentrations in swine manure have increased from 3 pounds per 1000 gallons to 9 pounds per 1000 gallons. When manure is agitated, hydrogen sulfide gas can be quickly released. Exposure to low concentrations of the gas for even a short period of time can cause health issues and at high enough concentrations can cause near instant death. A list of symptoms to different hydrogen sulfide exposures is provided in Table 1.


If you work around manure, monitors can be purchased to help keep you and your employees safe. A monitor, which is small enough to wear, ranges in cost from $99-$800 and will alert you if the situation is dangerous. This year as part of the manure applicators program participants were asked if they currently use any type of hydrogen sulfide monitoring equipment. On the commercial applicators survey, 5 percent of workers reported using a hydrogen sulfide monitor compared to 1 percent of confinement applicators survey. When asked about the likelihood of purchasing a monitor, 25 percent of commercial applicators and 31 percent of confinement applicators said it was likely that they would purchase a monitor (for a summary of this information see Figures 1 a and b below).

figure 1

There are numerous options available for monitoring hydrogen sulfide levels when working with manure. Below are links to four meters for you to take a look at and some pictures of what they look like.

  1. Honeywell GasAlertMax XT II
  2. BW Honeywell GasAlert Clip Extreme GA24XT-H
  3. BW Honeywell GasAlert Micro Clip XL 4-Gas Monitor
  4. Draeger Pac 3500 H2S Monitor
  5. RAE Systems ToxiRAE II

figure 2

In addition to considering purchasing a monitor, other practices to follow when agitating or pumping manure include:

  • Check to ensure all ventilation fans are working prior to pumping and that air inlets are open
  • Place a tarp over pump-out to help protect the applicator
  • Communicate with farmer and crew and never enter a barn during agitation and pumping
  • Listen for pig distress
  • Always be aware and alert as dangerous situations can develop quickly.

Your safety is important to us and we are always humbled to hear our messages makes a difference. Hear Kris talk about his recent experience when a farmer told him about remembering hearing about hydrogen sulfide in training and how to react.

Manure Foaming:

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Spontaneous foaming in swine manure pits is an ongoing challenge and has serious potential danger. Methane gas is trapped in the bubbles and creates the potential for fires and explosions, especially when the foam bubbles are rapidly destroyed and a spark occurs. Some times that are especially dangerous are during agitation, pumping, pressure washing, or activities like welding and hot work where slag might fall into the foam. If you are dealing with foam make sure you take the appropriate precautions to ensure your, your employees, and your pigs safety. Below are a few best tips for working with foam, or check out this video for a refresher on dealing with foam.

  • Provide continuous ventilation to prevent gas build-up. Increase ventilation during agitation to quickly dissipate released gases.
  • If disturbing the foam, turn off heater pilot light and other non-ventilation electrical systems, such as the feeding system, that might produce an ignition spark.
  • When pumping pits that are close to being full, pump without agitation until manure is about 2 ft. below the slats.

Foam Research
Over the last three years, a collaborative research project to understand and mitigate the causes of foam has been conducted by Iowa State University, the University of Minnesota, and the University of Illinois. I believe we have learned a lot about foam and its potential causes, so I wanted to share some of that information to you.

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Gas Production
Methane is always produced during anaerobic breakdown of manure, so when we store manure in a deep pit, we are going to generate methane. However, what we found is that foaming barns are consistently producing methane at faster rates than their non-foaming counterparts, often producing 2-3 times as much methane per day. This lead us to start asking why this might be happening. Through several dietary feeding trials what we have found is that diets higher in fiber tend to be less digested by the pig, which results in more carbon entering the manure storage. To microbes, this carbon is a food source, it’s the energy they need to grow and thrive. What we believe this shows is that recent dietary changes, like feeding more DDGS (a feedstuff high in fiber and protein) puts the fuel in the manure to build a more active microbial community. For example, a study by Dr. Brian Kerr, of USDA-ARS, tested how ration impacted the amount of carbon in the manure and found that a diet with 35% DDGS inclusion resulted in 40% more carbon in the manure than pigs fed a corn-soybean meal based ration. However, just putting the energy in the manure doesn’t guarantee foam, we also need to develop a microbial community that breaks it down quickly.

The second important part is we need something to stabilize the bubbles to have a foaming issue. Our work has found that the stabilizing agent are fine sized particles (2-25 µm) that are enriched in proteins, but it takes something to bind those proteins together. What’s that something? Well, we aren’t 100% sure yet, but our best data suggests it is a microbially produced poly-liposaccharide, a microbial goo. This microbial goo causes the foam to be very viscous, keeping the bubbles wet and making them last longer. One way of thinking about the chemistry of this stabilization is by comparing it to making meringue for your lemon meringue pie. In that case you take some egg whites (just the white, we want the protein which have hydrophobic, or water hating, and hydrophilic, or water loving, areas) and then start whipping it to entrain air into it. This alone isn’t enough though; we need something to stabilize the meringue. That’s where sugar comes in. Slowly add sugar and keep whipping and you’ll end up with a tasty meringue that’s light and fluffy and will persist for a long time. The sugars bond with the proteins and hold it all together. What’s happening in the manure is surprisingly similar; as the biogas moves through the manure it brings those bits of protein to the surface with it (just like when we separate the whites from the yolk to make meringue), it also churns them up and causes them to orientate themselves so their hydrophobic areas are towards the bubbles and the hydrophilic areas to the manure. When they react with some of that microbial poly-liposaccharide, stabilized foam results.

So all this is great, but I know what you are thinking. I have two barns, I treat them both the same; same pigs, same diets, they are as similar as they can be, but one foams and one doesn’t, explain that. Well, here is where it gets fun. It’s all about the microbial community that develops in the manure - in manures we tend to think there are lots of microbes that do roughly the same thing, but they might have slightly different ways of doing it. So which ones are most prevalent can make a difference on how the pit actually functions.

We know that dietary ingredients can influence microbial community and have good research that shows that both carbon and nitrogen contents influence the microbial community, but other factors, we couldn’t identify, seem to make as much of a difference. What we know is that for some reason foaming manures become enriched in certain microbes, things like ruminococcaceae, ruminococus, and bateroidales and depleted in other microbes. Our current studies are working to better correlate why these microbes become more prevalent as well as methods to alter and modify the microbial community and help prevent foam.

Leon’s Safety Message:

photoThis past year Leon Sheets shared the story, his story, of a fire/explosion at his swine barn. His important message reminds us all the importance of safety. "Farmers need to be careful whether they are pumping, power washing, or doing maintenance, when it comes to these accidents, we want no more, nobody else." Take the time to hear Leon’s message.

Iowa P-Index:

Phosphorus is an essential element for plant and animal growth, but when phosphorus is lost from fields it can increase algae growth in surface waters. This results in eutrophication, or excessive algae growth, which is a leading cause of surface water quality impairment. The challenge to farmers is to develop a plan that efficiently utilizes all sources of nutrients and at the same time maintains or increases agricultural profitability and environmental quality. The Iowa P-index as designed to help with this by assessing the risk of phosphorus loss.

The Phosphorus Index is a tool used to assess the potential for phosphorus (P) to move from agricultural fields to surface water. It uses an integrated approach that considers soil and landscape features as well as soil conservation and P management practices in individual fields. These characteristics include source factors such as soil test P, the rate, method, and timing of P application (from commercial fertilizer, manure, and other organic sources), and erosion. Transport factors include sediment delivery, relative field location in the watershed, soil conservation practices, precipitation, runoff, and tile flow/subsurface drainage. These factors are then combined to assess the risk of phosphorus loss from the field.

In general, since most phosphorus adheres to soil particles, factors that affect soil erosion are critical to phosphorus movement. If soil erosion is controlled, loss of phosphorus is less severe. In Iowa, RUSLE2, a software program, is used to estimate erosion from fields for manure management planning. On June 2nd ISU Extension and Outreach, in collaboration with the USDA-NRCS and Iowa DNR, is offering a workshop to train livestock producers and service providers on RUSLE2 and the Iowa Phosphorus Index.

The introductory level workshop provides hands-on software orientation, an introduction to the operating parameters, selection of input values and developing and saving management operations for RUSLE2. Additionally, field examples will be used in the workshop to determine risk calculations of the Iowa Phosphorus Index and how to incorporate these numbers into manure and nutrient management planning requirements. Soil sampling requirements, common errors and the Iowa DNR’s review process will also be discussed. More information and registration is available on-line.

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Manure Application Costs:

The cost of moving manure from farm to field is one of the most critical factors in making manure a resource for you farm. When it comes to deciding which field gives you the most bang for your buck or picking out the right size of equipment for your farm, the economics of moving manure to the field are often deciding factors. In this Manure Scoop data from a rate survey of custom manure applicators on the price they are charging for manure application is shared and I give a quick estimate of what I’d guess for costs.

Late Spring Nitrate Test:

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As we work toward reaching the goals set by the Iowa Nutrient Reduction Strategy, you may want to consider utilizing split fertilizer application. Split fertilizer application can increase nutrient efficiency and reduce nutrient loss. Additionally, there is less investment in the field if you are forced to replant to soybeans after weather related losses or planting delays and may allow you to gather additional information about this year’s market and growing conditions. The cost of making a second fertilizer application trip across the field and potential for rainy weather are deterrents of spring nitrogen application.

Often times when we switch to split application our general plan is be to apply 50-60% of the nitrogen recommendation in the fall or early spring, and then to sidedress the remaining 40-50% into the growing crop. An alternative approach is to determine our sidedress amount using the late spring nitrate test (LSNT). The late spring nitrate test is a nitrate only soil test should be done when the plant is 6-12 inches in height; this allows for spring nitrogen losses or gains to be reflected. Soil samples are taken at a depth of 12 inches. The test provides us with plant-available nitrogen concentrations in the soil before the plant begins rapid uptake of nitrogen.
Fields should be divided into 1 to 10 acres test areas that have similar management histories and soil types. Within each management zone 16 to 24 soil cores should be collected. Banded fertilizer or manure could bias your results; to avoid this sampling should occur in a pattern relative to the corn row to eliminate the effect of the banded application. For example, go to the first sampling location in your management zone and pull the first soil sample in the row, then move to your next sampling spot and pull the soil sample one-eighth the distance between rows, go to your next sampling location and pull the sample one-fourth the distance between rows, and continue this pattern.

Research recommends 25 ppm of nitrate-nitrogen in the top 12 inches of soil to produce maximum yield; however, the interpretation of the results vary with cropping system, manure history, and even weather conditions prior to and after sampling. One of the challenging parts of using the late spring nitrate test is determining the "critical" soil nitrate concentration you are trying to achieve.


In manured fields, a "critical" soil nitrate-nitrogen concentration of 15-20 ppm is recommended. This is lower than non-manured fields because manure application provided additional organic matter that will be mineralized after the time of soil sampling and become available to plants later in the season. Using your results, you can calculate the amount of nitrogen that would be recommended to sidedress. The formula for calculating nitrogen application is if your soil test was greater than 20 ppm then 0, otherwise (20 ppm - soil test nitrate) * 8 = lbs of N/acre to apply. Alternatively, table 1 provides a way to select a sidedress nitrogen application rate. In this table excess rainfall would be May precipitation that exceeded 5 inches, normal rainfall should be used for other cases.
As with any new fertility management program, first-time users are encouraged to experiment with the test in small areas before using it to guide fertilization on all their fields.  As with most recommendations this test is intended to maximize profits when used across many years and sites, not to give the “perfect” rate in a specific year.

For more information related to using the Late Spring Nitrate Test please see, ISU PM1714- Nitrogen Fertilizer Recommendations for Corn in Iowa. More information on best management practices for reducing nutrient loss from agriculture can be found in SP435 - Reducing Nutrient Loss: Science Shows What Works.

Winter Manure Application:
I know summer is coming, but I wanted to update you on a recent report about winter application. "The Iowa Policy Project" recently released a report, 'Saving Resources: Manure and Water Assessing Agricultural Policy Implications for the Mississippi River Basin,' comparing Iowa’s winter manure application policies to those of Ohio. I encourage you to take a look at this publication to see the summary of research they provide, their evaluation of current regulations, and what this might mean for your operation in the future.

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If you are still in need of training, there are still several options for getting your manure training completed. You can get certification by: 1) contacting your County Extension Office to make an appointment to watch the appropriate training video; 2) contacting your local DNR field office to schedule an appointment to take the certification exam; or 3) completing your training on-line!

To utilize the on-line option, you will need a computer, smartphone, or other internet capable device and an internet connection that will support streaming video. To find the online training site, please go to MAC E-Learning. Still have questions about the on-line training options? Rachel provides answers to our most frequent questions.

A quick reminder about who needs manure applicator training.

  • If you are in the business of hauling or applying manure, you will need a commercial manure applicator certification.
  • If you haul/apply manure from a confinement animal feeding facility with more than 500 animal units, you will need a confinement site manure applicator certification. You must complete your annual manure application certification training to keep your three-year license current.

Is my hauler certified?

Are you hiring someone to haul manure at your farm? If so, take the time to make sure that are certified. You can find a list of currently Certified Commercial Manure Applicator Business at the Iowa State IMMAG Commercial Manure Applicator site  or if you are curious about where these 551 business are located you can check out this map.


The IMMAG Events page is a compilation of manure management related events. Please check the events page often for new listings. nd effective planting season,

RUSLE2 Soil Loss Workshop:
Polk County Extension Office in Altoona
June 2nd from 9 a.m. to 4:30

Iowa State University Extension and Outreach, in collaboration with the USDA-Natural Resources Conservation Service and Iowa Department of Natural Resources, has scheduled a workshop to train livestock producers and service providers on how to use the Revised Universal Soil Loss Equation 2 (RUSLE2) and the Iowa Phosphorus Index in nutrient management and manure management plans. More information and registration is available on-line.

North American Manure Expo
London, OH
August 3-4, 2016

The 2016 North American Manure Expo is schedules for August 3rd and 4th near London Ohio. The show provides a great opportunity to see equipment demonstrations, tour some farm, and hear and see the newest innovations in manure. More information is available at the show’s website.

Livestock Waste 2016
Recent Advances in Pollution Control and Resource Recovery for the Livestock Sector
Galway, Ireland
August 10-12, 2016

The 2016 Livestock Waste conference will be held in August in Galway, Ireland.  The conference will cover policies and regulations on animal manure, pollution control technologies, resource recovery practices, and greenhouse gas emission mitigation. More information can be found on the conference website.

Livestock and Poultry Environmental Learning Center Webinar
May 20, 2016

On May 20th the Livestock and Poultry Environmental Learning Center will be holding a webinar on "Implementation and Experiences of NAQSAT around the US." NAQSAT is the National Air Quality Assessment tool and is designed for voluntary use by producers and planners to assess opportunities for reducing air emissions around a livestock our poultry operation. The webinar will discuss and overview of the tool and what has been learned from the on-the ground training. More information can be found here.

Wishing you a happy safe and happy spring,

Dan Andersen
(515) 294-4210
Twitter: @DrManure

Angie Rieck-Hinz
(515) 231-2830
Twitter: @iowamanure

Rachel Klein
(515) 294-6685

Melissa McEnany
(515) 294-9075

Iowa Manure Management Action Group

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