IMMAG Updates

June 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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Options Available for Livestock Odor

As summer arrives, so does the return of outdoor living.  As people head outdoors, concerns increase about odor from livestock, feed, and manure, either from storage or land application. Handling odor emissions and dust at your livestock operation becomes extremely important this time of year.

Resources are available to help you find mitigation techniques that will best suit your operation. The Air Management Practices Assessment Tool (AMPAT) was developed by Iowa State University Extension and Outreach specialists, with major funding from the National Pork Board, and is available on-line. This tool allows you to compare different practices to reduce odor and emissions of gases and dust caused by animal production.

To use the tool, go to the website and select an odor-source category (animal housing, manure storage and handling, or land application). Each category compares different odor mitigation techniques, as well as the effectiveness of mitigating different gases. This is done using an easy to read, color-coded score card, which allows you to quickly identify the level of impact of each technology. If you want to learn more about a technology, simply click on it, and you are directed to more resources, including a short video about how it works, cost considerations, and the pros and cons.

Are you wondering about the science behind the ranking system? A summary published academic studies used to develop the rankings was recently published and is provided. A team of ISU researchers reviewed journal articles regarding reducing odor and gas emissions from livestock production. The study found about 25 percent of all mitigation practices examined made it to field trials, as only a few of the practices are successful enough in the lab setting to make it to the field. The article is available on-line and will be used to strengthen the performance summary in AMPAT.

Vegetative Barriers

vegetative barriers

One technique that always comes up first is landscaping; though it isn’t the most effective practice, it does offer a lot of bang for the buck because it is generally low cost to implement and it does provide a medium impact on ammonia, odor, and dust and particulate from the farm. The trees can do a couple things to help with odor control from the farm, including dilution and dispersion as barn air from the ventilation fans is mixed, and lifted up and over the trees. Additionally, the wind pattern encouraged by the trees can cause dust (and odorants in the dust) to settle out in the quiet zone directly downwind of the vegetation (similar to how you see snow settle around windbreaks during winter). Finally, trees are often aesthetically appealing and can serve as living screening that helps your farm look visually appealing to those driving by.

Although vegetative barriers can be effective options, I’ve been to several presentations where people have suggested that these barriers could also be used to grow fruit and I have to admit, I was instantly intrigued by the idea (memories of homegrown strawberries will do that to a person). One that I kept hearing about was aronia berries. You can see more about a hog farm that planted aronia berries around their farm on the Coalition to Support Iowa Farmers website. Over the next couple months, we’ll provide a closer look at some of the technologies listed in the Air Management Practices Assessment Tool (AMPAT) and what role they might have in animal production in Iowa.

Manure Nutrient Availability

Figure 3. Manure injection for improved nutrient managementIowa State University Extension and Outreach recently revised the ranges for manure nutrient availability for crops for dairy and beef cattle manures. Drs. John Sawyer and Antonio Mallarino posted an article about the changes. The new guidelines are available in the updated "Using Manure Nutrients for Crop Production" which you can download for free at the ISU Extension store. Essentially, the range of first year nitrogen availability in beef and dairy cattle manure was widened from 40-50 percent to a range of 30-50 percent and 1st year phosphorus availability was changed from 60-80 percent to 80-100 percent.

So what do these changes mean to you when planning manure applications? In terms of phosphorus, it probably will have little to no impact, unless your soils are in the low category. First year phosphorus availability generally isn’t a deciding constraint on how much manure you need to apply. However, if you are applying based on nitrogen needs, it might change your rates a bit.

Typical dairy manure has approximately 22, 8, and 19 lbs. per 1000 gallons of N, P2O5, and K2O (though concentrations can vary substantially from one farm to the next so sample the manure rather than relying on book values). Based on the previous version, estimate of nitrogen availability from dairy manures we’d have applied between 13,500 to 17,000 gallons per acre to corn following soybean (assuming injection and wanting to supply about 150 lbs. of N an acre). In the updated version we’d be looking at between 13,500 and 23,000 gallons per acre.

Remember, these ranges account for variation in the organic and inorganic forms of nutrients in manure, differences in production systems, bedding amounts and types, and storage and handling differences. Testing your manure for total nitrogen and ammoniacal nitrogen and keeping good records of how much manure is applied and how your crops perform, can help you tailor these suggested availabilities to your farm and field conditions.

June Dairy Month

photo It's been hot, but these cows are staying cool for dairy month with the with stir fans giving them a nice breeze. No fan on you? Try a cold refreshing class of milk or a delicious ice cream cone to help these girls celebrate dairy month.

As June is dairy month, and like most, I am extremely grateful for the hard work that goes into every glass of milk, every block of cheese, and every scoop of ice cream I devour. To help celebrate Dairy Month, the next few section will be devoted to dairy manure management issues.

A 2012 survey of Iowa dairy producers conducted by Iowa State University, found tie-stall or stanchion dairy operations typically utilized daily spreading as part of their manure management, while free-stall operations usually used liquid manure storages. This is one of the things that make dairy manure management so interesting - options and diversity. Every dairy farm seems to be set up just a little different and as a result, handle their manure just a little differently.

So with that in mind, we are going to take a brief tour around some of the latest dairy manure management trends.

Sand Bedding

Comfortable cows tend to be more profitable. Currently, producers tend to use sand, organic beddings, mattresses or waterbeds for stall surfaces.  All these can be appropriate choices for bedding, just requiring the right management to be used successfully. Each has their benefits (effect on cows) and associated costs over time that need to be evaluated when making a decision for your operation.

When it comes to the world of manure, sand is both a blessing and a curse. Sand can be managed to provide a comfortable surface that keeps the cow clean and sanitary, but by its nature it’s also heavy and abrasive, which can make moving it with the manure a challenge. However, it’s important to note that not all sand is the same. The properties of the sand will influence not only your cow comfort, but also your ability to recover and recycle the sand.

Sand Settling Lanes

Figure 5. Sand settling LaneSand settling lanes are often used on dairy farms to recover and clean used sand. Recently, I wrote a little post about a little of the science behind settling lanes. If you think about what this means, it shows often times coarser sands will be a bit easier to collect as the bigger particles settle faster, but this has to be balanced with cow comfort.

I received a few comments about this post and wanted to touch on them briefly. First, different sand will lead to different settling characteristics. Particle size greatly influences settling rate. Secondly, cleaner water can really help improve settling. The cleanliness of the water influences its viscosity and the rate and the way things settle.

Sand and Manure Application

These days there has been a lot of conversation about soil health. Often times it is synonymous with trying to build organic matter levels in the soil. Certainly, manure being a source of fresh organic matter can have positive impacts on soil organic carbon levels, but what if we are bedding with sand. Should we expect the sand laden manure to change our soil? The truth is its certainly possible, but given our normal manure management practices it would take a while to have a noticeable impact, somewhere between 50-100 years. What does this mean for your manure decisions? Well, it is something you should think about as you select bedding, but it is just one aspect of why a bedding is selected.

To put this into some perspective, 2 tons per acre (which is roughly the amount of sand I estimated would be applied) is also in line with the tolerable soil loss limit for many Iowa soils. If you ask me, I’d be more concerned about the loss of two tons from erosion and the impact that has on soil quality, than the addition of two tons of sand.

Manure Stacking Pads

Many smaller dairies (or other small farms) are starting to look at manure storage options for their farms. Often times, these farms are working with solid manure and have typically practiced daily manure application. However, many of these farms have come to accept that there will be some days that they probably want to stay out of the field due to wet field conditions. We know spreading during rain, especially on nearly saturated soils, can lead to compaction and even runoff of the manure nutrients.

To help make sure they are appropriately managing their manure nutrients, many of these farms have started looking at manure stacking pads. These facilities generally have three walls to help contain the manure, a poured concrete floor so it is easy to drive on, and a least one wall stout enough to buck against to scoop the manure out.

These facilities don’t have to be big, but to be successful theyManure stacking pad at a small dairy. should be sized to provide the flexibility your farm needs to choose manure application dates based on the current soil in weather conditions. Often times, this means adjusting manure application by 3-4 days at a farm this size. The size storage you pick should be based on the number of animals at the farm and the amount of manure they produce, how often you anticipate cleaning out the holding pad, and funding available for building the facility. Generally, I’d prefer to see these storages with a few months’ work of manure storage capacity but it really depends on your manure management goals and what the facility you are hoping to accomplish with the facility to determine the appropriate size for your farm.

Feed & Silage Storage

Silage leachate is very acidic and high in oxygen demand, so controlling runoff from silage is important for protecting water.Feed storage is important not only from maintaining feed quality to keep your animals productive, but also from an environmental perspective. While it might not come to mind as quickly as manure when it comes to water quality, leachate from silage can be just as harmful to fish and surface waters. Runoff and leachate from animal feeds is considered a process generated wastewater and state and federal regulations require it be managed appropriately, this means keeping it out of streams and rivers to help keep waters clean.

Feed storage shed. The roof keeps the feed dry and prevents runoff from carrying nutrients to streams and rivers.When it comes to best environmental practices for your feed storage areas, it generally comes down to keeping clean water clean, and making sure we capture and treat dirty water. As general best management practices a few tips are recommended:

  • Monitor crop moisture during harvest for silage; wet silage is more prone to leachate (aim for around 65% moisture)
  • Keep all feedstocks covered; keeps them drier and higher quality and means no chance for runoff.
  • Direct surface water around your feed storage areas
  • Provide a vegetative buffer around the feed storage area to filter any runoff water


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,

Iowa Swine Day
Leading experts focusing on topics vital to today’s pork industry.
Scheman Building
Ames, IA 
June 30, 2016

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.

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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