IMMAG Updates

September 2015

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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Manure Sampling and Manure Nutrient Management Planning
       Manure can serve as a great fertilizer source to support crop growth and provide significant cost savings as compared to purchase of commercial fertilizers. Below are some resources that you might find helpful as you try to get the best use of your manure nutrients for crop production while protecting the environment.

In particular, knowing the amount of different crop nutrients in your manure is a key step to developing and implementing a good plan about the best way to use them. At times, it may seem like a hassle to collect a manure sample and change your planned application rate based on what you get, but it is worth it. There is a saying that you never walk in the same river twice; the same tends to be true with manure. Its nutrient content depends on so many factor - the ration of the animal, the weather conditions throughout the year, etc. - that even though we tend to manage our barns similarly every year, we can still get some larger differences in nutrient content. This variation is what makes manure nutrient sampling valuable - if we knew what was going to be there the better information on the manure’s nutrient content wouldn’t be necessary. Last year I came up with a model (read more about it here) to estimate the economic value of manure sampling. Updated results based on current corn and nitrogen prices ($3.80 a bushel for corn and $0.39 per pound of N) are provided below. As prices change and margins get tighter don’t cut back on sampling, knowledge is power and getting the best use of your manure helps minimize the risk by avoiding purchase of commercial fertilizer.

Estimated value gained by collecting and using a manure sample to set your manure application rate.



Manure Test Value ($/acre)


During Application

Manure Type

Crop Rotation

N limited

P limited

Swine Slurry





Continuous Corn



Layer manure





Continuous Corn



Dairy Slurry





Continuous Corn



Beef feedlot scrapings





Continuous Corn




Manure Pumping Safety

safetyDid you know it is National Farm Safety & Health Week? For those of us who work with manure, safety should be an especially important aspect of our activities. The decomposition of organic matter in manure results in the release of several gases, ammonia, carbon dioxide, methane, and hydrogen sulfide among them. Although all are potentially dangerous, hydrogen sulfide tends to be the one of most concern when we are pumping and agitating manure. Hydrogen sulfide has an intense rotten egg smell, so it is relatively easy to detect its presence, even in very low concentrations. However, after breathing it for a short time your sense of smell will become fatigued and you lose the ability to detect it. Just as importantly, since we can smell it at such low levels, there is not a clear indication of when it reaches potentially hazardous conditions that we can detect without the use of analytical instruments.

Good agitation practices like avoiding rooster tailing, making sure agitator nozzles are at least 1 foot below the manure surface at all times, making sure that these nozzles aren’t directed at pillars are walls can help reduce the rate that hydrogen sulfide is released from the manure but some will still be released, but they don’t provide a guarantee.  Similarly getting your ventilation system set up correctly and covering  the pump outs you are using for agitation and withdrawal with a tarp, so they don’t become air inlets to the barn, is also extremely important; however, even if you are doing everything right there still might be issues. In the last few years, we have since more incidents despite following these best practices. This might in part be due to higher sulfur levels in our manure. Swine manures used to average about 3 lbs. sulfur per 1000 gallons of manure, but recent sample collection from 70 farms within Iowa showed we are currently averaging closer to 9 lbs. sulfur per 1000 gallons.

While everyone needs to be cautions to avoid pig losses, be especially mindful of animal caretakers and other employees. Make sure to remind everyone to stay out of the building during manure agitation and removal and place log-out tags on the door to make sure everyone is aware of the danger (door tags from National Pork Board). Keep ventilation systems running at elevated levels for a few hours after completing manure removal to help prevent pig loss. Additionally, be mindful of where employees are outside the building and the environmental conditions. In several cases I’ve heard or seen elevated concentrations of hydrogen sulfide in the air even further ways from the barn.

Foaming Swine Manure
foamAn issue we are dealing with and seeing in greater numbers again this fall is the occurrence of foaming pits. Some foaming may be typical in manure storages, but the foam that has recently been causing problems is a persistent and fast-growing substance that has a mucous-like texture. Methane gas is trapped in the bubbles and creates the potential for fires and explosions, especially when the foam bubbles are rapidly destroyed in the presence of a spark source, such as during agitation and pumping or power washing the barn. With fuller manure pits and warm fall temperatures, the foam condition of manure can change quickly, so be vigilant in checking your pit for foam accumulation.

The Iowa Pork Producers Association recently put out stickers that can be posted on your barn door to help remind you and those working in our around your facility of the risks. Take this opportunity to review safety procedures for your operation and develop an emergency action plan on how to respond to foam with your employees.

Manure Spreader Technology - Not your Grandpa’s Manure Spreader
photoAnother manure application season is arriving, so what better way to prepare than to talk a bit about manure spreader technology? At first, manure spreaders might seem simple - they are used to get manure from point A (the barn or barnyard) to point B (the field). However, they have to do so much more than that.  Manure spreaders not only have to get manure from the barn to the field, but once they are in the field they have to evenly spread that manure over the field at the correct rate to make sure we are supplying our crops with the nutrients they need without adversely impacting the environment. The spreaders we have today have incorporated new techniques to help ensure we are consistently hitting our desired application rate and getting our manure nutrients where we want them. Today’s spreaders are often equipped with on board rate controllers, GPS tracking formation, flowmeters, and a pump or valve that changes the flow to make sure we are hitting our rates. For more information on how these systems work visit The Manure Scoop.

Iowa DNR Spill Number
Manure application season is coming quick. Did you catch that the Iowa DNR spill number chanced? If you haven’t already my sure you get that number updated in your phone or where you keep it posted in your manure application tractor so you’ll have it handy should you need it this manure application season. The new number is: 515-725-8694.


Fall manure application season is approaching, are you certified? Just a reminder that if you are in the business of applying manure (a commercial manure applicator) or have more than 500 animal units and apply manure from your  farm (a confinement site applicator) you must complete your annual manure application certification training. You can get certification by: 1) contacting your County Extension Office to make an appointment to watch the appropriate training video; or 2) contacting your local DNR field office to schedule an appointment to take the certification exam. All certification requirements must be met prior to applying manure. Final touches to the on-line training system are occurring and release is expected soon.


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

The Livestock and Poultry Environmental Learning Center will be hosting a webinar on October 16 at 1:30 on Mortality Management Options During Avian Influenza Outbreak. The webcast will provide a current update of the outbreak and highlight mortality management options, with emphasis placed on proper mortality composting procedures and lessons learned from the 2015 outbreak. More information is available here. To participate, on the day of the presentation go to and log into the virtual meeting room.

USDA NRCS has scheduled a webinar for October 7th at 1PM to discuss their New Emergency Animal Mortality Management Conservation Practice Standard and Highly Pathogenic Avian Influenza. Participants in the webinar will get a chance to hear about the new conservation practice standard (CPS 368) and about the USDA APHIS emergency response in the current Highly Pathogenic Avian Influenza situation.

Additionally, USDA NRCS will be hosting a webinar on the “Use of Solid-Liquid Separation Alternatives for Manure Handling and Treatment” on October 27 at 1 PM. This webinar will be led by Jeff Porter, P.E. and a member of the national Animal Manure and Nutrient Management Team in Greensboro North Carolina. He will discuss different solid-liquid separation alternatives and provide some guidance on selection for different farms. More information on the webinar is available here.


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

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

Iowa Manure Management Action Group

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