IMMAG Updates

August 2017

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 Expo Returns to the Midwest

The 2017 North American Manure Expo will take place August 22 and 23 at the University of Wisconsin’s Arlington Research State near Arlington, Wisconsin. The expo begins with tours on August 22, followed by the opening of the trade show and an agitation demonstration at the center’s dairy lagoon. Education sessions and manure application demonstrations, including side-dressing liquid manure onto growing crops, will be featured on August 23. Registration is free and available here.

Impact of Swine Manure Application Timing on Drainage Water Quality– 2016 Results

Brian Dougherty, Iowa State University

A three-year study, starting in 2016, at the Northeast Research and Demonstration Farm in Nashua, IA, began evaluating the impacts of various cropping and nutrient management systems on nitrogen and phosphorus loss through subsurface tile drainage. This is particularly interesting to livestock producers regarding the impacts of swine manure application timing on drainage water quality. The study allows for comparisons between early fall manure application (soil temperatures above 50°F) with and without a cereal rye cover crop and late fall manure applications (soil temperatures below 50°F). Late fall manure with and without a nitrification inhibitor is also being compared to spring manure application. Results from this study will give producers valuable information regarding the water quality impacts of different manure management practices.

figure 1.

First-year results from 2016, show adding a cereal rye cover crop resulted in a significant reduction in annual average nitrate-N levels and overall N losses via subsurface tile drainage water. In corn plots, early fall manure had the highest annual average nitrate-N concentrations of 20.5 mg/L, followed by late fall manure with 15.7 mg/L, and early fall manure with a cover crop at 11.3 mg/L (Figure 1).  In a system with early fall swine manure application (when the soil temperature is above 50°F and early October in this study), nitrate-N concentrations were reduced by 45% when a cereal rye cover crop was added prior to corn. The nitrate-N concentrations from early manure with a cover crop were 28% lower than late manure (early November). Similarly, nitrate-N concentrations were 38% lower with cereal rye prior to soybeans.

figure 2.

Another part of this study focused on timing spring vs. fall and how the use of Instinct with fall manure impacted nitrate nitrogen concentrations in tile drainage water. No significant differences in nitrate-N levels between late fall manure, late fall manure with nitrification inhibitor, and spring swine manure applications to continuous corn (Figure 2) were seen.  No significant differences in dissolved phosphorus concentrations were observed between any of the treatments.

The first-year results suggest delaying fall swine manure application until soil temperatures are below 50°F and using cover crops can benefit drainage water quality. The plots will continue to be monitored in 2017 and 2018 to get a better estimate treatment differences over a range of weather conditions and to evaluate the impact these different practices had on crop yield.

Iowa NRCS Updates Pertaining to Animal Feeding Operations

Mark Garrison, NRCS Environmental Engineer (515) 323-2226,
Natural Resources Conservation Service (NRCS) provides technical and financial assistance to eligible livestock producers to assist with manure and nutrient management from their operations.  This article provides updates of interest to producers and technical service providers who may be interested in or are pursuing assistance from NRCS.

  • Open feedlots are an inexpensive but potentially environmentally risky way to operate an animal feeding operation.  IA NRCS offers potential incentives to producers to decommission/remove open lots and convert to a roofed, confinement operation.  A recently published pamphlet: “Open Feedlot Management – Best Options” offers information regarding open lot to confinement conversion.
  • IA NRCS is in the process of updating the Waste Facility Storage – 313 standard.  This standard provides technical guidance for planning, design, and installation of agricultural waste containments.  Some of the changes include:  modification of structural design requirements to account for changes in accepted concrete and timber design, improvements in safety criteria, changing requirement of staff gauge from optional to required, and the addition of criteria specific to solid manure stacking facilities.  Specific proposed changes include the removal of the IDNR Open Feedlot Effluent Alternatives for Open Feedlot Operations as an acceptable design alternative to meet NRCS requirements.  Also, a minimum design period is being considered for storage facilities to better integrate animal waste systems with current management and cropping systems.
  • A recently published IA Instruction: “Requirements for Subsurface Geologic Investigations for Animal Waste Storage Facilities” provides requirements that apply to technical service providers and other non-NRCS engineers who are providing technical assistance for NRCS programs.  Compliance with this instruction will help ensure geologic investigative requirements have been fulfilled as noted in the deliverables of the appropriate conservation practice statement of work. 
  • Another instruction of interest for technical service providers for NRCS programs is the “Technical and Financial Assistance for an Animal Feeding Operation and the Associated Land Application of Manure Through a Comprehensive Nutrient Management Plan (CNMP)”.This document provides guidance for the specific procedures, roles and responsibilities, and administrative and technical checklists to be used when technical service providers are involved in the conservation planning process for animal feeding operations. 

For more information regarding NRCS technical and financial assistance visit your local NRCS field office or or visit the NRCS website.

Manure Application Uniformity Field Days

The past two months we hosted demonstrations on manure application uniformity. Four field days were held across the state. First and foremost, we’d like to thank those who attended, the companies who helped host these events, and all those involved in the planning and execution of these events. Over 150 people showed up to learn more about using manure as a fertilizer resource, be informed on the science behind selecting application rates, and see some equipment demonstrations on different injection styles and evaluate how uniform manure application is at different rates.



The Manure Scoop

Last month I wrote about how uncertainty impacts our manure application rate selection but received a great question asking me if my math was correct. The latest blog takes a pictorial look at the same question to see if we reach the same or a slightly different conclusion.

ISU Extension and Outreach Offers Iowa Drainage School

Agricultural drainage is an important management tool for crop production in many areas of Iowa. The design, installation and maintenance of drainage systems is the focus of the Iowa Drainage School scheduled for Aug. 22-24 at the Borlaug Learning Center on the Northeast Research and Demonstration Farm near Nashua, Iowa. The three-day school features classroom lecture and discussion combined with team problem solving and field exercises. Student teams will survey and design a drainage system for a sample area of the host farm, using concepts learned during classroom discussion. By attending this school, participants will be able to plan and lay out subsurface drainage systems and work out project costs. There also will be in-field equipment and installation demonstrations. Additional program information, online registration, and school location are available at


August 22-23, 2017 - North American Manure Expo, Arlington, WI

August 22-24, 2017 - Iowa Drainage School, Nashua, IA


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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