IMMAG Updates

November 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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Design of Water Quality Practices Covered in Workshop

The design, siting and layout of new practices currently being considered for water quality improvements of farmland drainage will be the focus of a workshop scheduled for Dec. 15 in Fort Dodge, Iowa.  It will provide information essential for designing and planning bioreactors, managed drainage with controls structures, saturated buffers, and wetlands.  Registration and additional information can be found in an online brochure. Registration can also be done by contacting the ISU Extension and Outreach Webster County office at 515-576-2119 or Registration is $150 and includes morning refreshments, lunch, and workshop materials. Registration cost moves to $175 if done after Dec. 9.  The workshop is presented by ISU Extension and Outreach, the Iowa Soybean Association, and USDA Agricultural Research Service. Additional information, including an agenda, can be found here.

Iowa Manure Management Plans: Maximum Return to Nitrogen versus Yield Goal Method

When preparing manure management plans, livestock producers must decide whether to based nitrogen application rates on the yield goal method or maximum return to nitrogen. To calculate the nitrogen rate using yield goal method, the farmer determines the optimum yield of the crop and then multiples the yield by a crop usage rate factor for the specific crop. The required nitrogen rate is then adjusted for ammonia losses during application, the nitrogen availability of the manure, and any previous legume crops grown in the field. The optimum yield for each county is either set to the average of the last 5-year county yields plus 10 percent or the average of the highest 4 out of the last 5-year county average.

Maximum return to nitrogen (MRTN) uses economic return to N application found in research trials as the basis for the suggested N rate. The average of N responses accumulated from a population of N rate trial sites is used to estimate the point where net return is the greatest, by identifying they point where the next added unit of fertilizer results in a yield increase that based on the value of corn is equal to the price of the unit of nitrogen. The Corn Nitrogen Rate Calculator can be found at: and can assist with these calculations. The program generates an estimate of what fertilizer rate will give you your maximum return to nitrogen after providing information about corn price, nitrogen fertilizer price, crop rotation, and state or region.

Check out the Manure Scoop blog for a detailed comparison of the two methods. A summary of how they compare is provided in Figure 1. In many counties the MRTN suggests a slightly lower nitrogen application rate than would be predicted by the yield goal method. Depending on your manure application timing, adjusting your manure application to provide the amount of available nitrogen your crop needs might allow you to make sure even more of your acres can take advantage of a natural fertilizer source.

Figure 1

Additional resources for selecting your nitrogen application rate are:
PM-1714 "Nitrogen Fertilizer Recommendations for Corn in Iowa"
PM-2015 "Concepts and rationale for regional nitrogen rate guidelines for corn"

Manure Movement in Soil

Have you ever wondered how manure moves in soil? The latest Manure Scoop blog takes a look at what the manure band typically looks like and discusses how soil properties impact it. As a bonus, take a look to see a manure injection cake that you can share with your family over the Thanksgiving as you discuss the back end of animal production!

Figure 2


Thanksgiving Dinner and Iowa Agriculture

Figure 3Thanksgiving has always been one of my favorite holidays - to me it always represented another year and the conclusion of another harvest season. As I take a few minutes to reflect on what I’m thankful for this year (besides being able to talk about manure and helping animal production remain an important part of feeding the world - which really might be the best job ever) it made some sense to think about where the food for the Thanksgiving table is grown (and some manure facts to go with it).

Turkey - Iowa ranks 9th in turkey production with about 130 farms producing 11 million turkeys every year. Its estimated that this is about $220 million in on farm production, $300 million in processing, and has a total economic impact of about $1.5 billion dollars! Every year about 300,000 tons of turkey litter are generated that contains almost $10 million dollars of fertilizer value!

Pumpkin Pie with Whipped Cream - Alright, almost all the pumpkins are grown around Morton Illinois, where 90% of the US pumpkin supply comes from! But for those of us who grow our own pumpkins what we are looking for is that whipping cream and delicious butter for those roles. Iowa dairies are 12th in milk production making 4.35 billion pounds of milk every year. Did you know that a typical dairy cow will drink about 30-50 gallons of water, make about 8-12 gallons of milk, and product around 14 gallons of manure a day?

Green beans - You caught me, Wisconsin is the leading producer of green beans, but have you ever had bacon in your green beans? It’s delicious! Iowa is the nation’s leader in pork production with a few more than 20 million pigs in the state at a given time. Iowa swine farmers have improved water conservation at their farms by switching from nipple water’s to wet-dry feeders, change estimated manure production from 1.2 to around 1 gallon per pig per day. Same great fertilizer, but fewer gallons an acre.


The Livestock and Poultry Environmental Learning Center will be hosting a webinar on Friday, December 16 at 1:30 pm on Pathogens 101. More information about the webinar and how to participate can be found here.

Commercial Manure Applicator training is scheduled for January 5, 2017. Click here for a list of County Extension Offices hosting this event. Commercial applicators are required to attend 3 hours of training annually or take and pass the certification exam annually. Certification requirements must be completed prior to handling, hauling, or land-applying manure.

Dates have been announced for the 2017 Confinement Site Manure Applicator Workshop. A complete list of workshops can be found here.

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

Rachel Kennedy
(515) 294-6685

Melissa McEnany
(515) 294-9075


Iowa Manure Management Action Group
Twitter: @iowamanure

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