Journal of Nutrient Management - Quarter 2 - 2020

Page 1

Published by W.D. Hoard & Sons Co.

May | 2020

Journal of

Nutrient Management

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Farming with an open door policy Changing manure composition with diets Widen the manure application window

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2020-05-06 10:02 AM


Volume 1 | No. 2

Journal of


12 Farming with an open door policy

4 6 10

Essential farmers and essential nutrients

Macropores contribute to tile flow Low disturbance application has several benefits

18 20 22

Sample before you spread

Kim Zilverberg

Manure’s contribution to carbon footprints


In the Field . . . . . . . . . . . . . . 6 Policy Watch . . . . . . . . . . . . . 8 Manure Minute . . . . . . . . . . . . 9 On the Move . . . . . . . . . . . . 24

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EDITORIAL OFFICE 28 Milwaukee Ave. West Fort Atkinson, WI, 53538 WEBSITE EMAIL PHONE (920) 563-5551

Places To Be . . . . . . . . . . . . 26

Photo by Abby Bauer, Managing Editor.


Fresh Paint . . . . . . . . . . . . . 25

ON THE COVER One of the first signs of spring on the farm is manure application. Recycling livestock manure by delivering these nutrients to fields for crop growth is one of agriculture’s finest sustainability stories. Armed with more knowledge and enhanced equipment, our ability to utilize this valuable resource continues to expand.

Find us online at:

Jane Griswold

Widen the manure application window

First Thoughts . . . . . . . . . . . . 4

Changing manure composition with diets

Andy Dellava

Jenna Zilverberg




Journal of Nutrient Management (ISSN# 26902516) is published four times annually in February, May, August, and November by W.D. Hoard & Sons Company, 28 Milwaukee Ave. West, Fort Atkinson, Wisconsin 53538 Tel: (920) 563-5551. Email: info@ Website: Postmaster: Send address corrections to: Journal of Nutrient Management, PO Box 801, Fort Atkinson, Wisconsin 53538-0801. Tel: (920) 563-5551. Email: info@ Subscription Rates: Free and controlled circulation to qualified subscribers. For Subscriber Services contact: Journal of Nutrient Management, PO Box 801, Fort Atkinson, Wisconsin 53538, call (920) 563-5551, Copyright © 2020 W.D. Hoard & Sons Company. ALL RIGHTS RESERVED. Content may not be reproduced or used for any commercial activity without express written consent from W. D. Hoard & Sons Company.

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Abby Bauer Managing Editor

n a matter of just a few months, life as we knew it came to a halt. Health concerns mounted, travel all but stopped, events were canceled, and some every day goods became difficult to find. This global pandemic rocked our country to the core, both personally and economically. What hasn’t stopped is agriculture. Early on, anyone farming or working in agriculture was deemed an essential employee by the government and was asked to continue working while other businesses closed and people sheltered in place. The value of agriculture and a stable food supply was magnified. Of course, we knew farming was essential all along, but hopefully more consumers now feel that way, too. As winter turned to spring and spring into summer, fields were prepared and planted. Pandemic or not, there was manure hauling, tillage, and planting to do. I hope that when this magazine reaches your mailbox, you are in a good spot with planting and have crops that are growing well. We can’t control the weather, but we can give crops other tools to succeed, including the right nutrients at the right time. These essential nutrients can be delivered through manure, a plentiful by-product on any livestock farm. I was at a conference this winter (prepandemic) and sat at a table with a gentleman who ran a custom manure hauling business for 30 years. We were talking about some of the changes he has seen over time. He said that early on in his career, when he asked farmers where they wanted the manure applied, they would commonly reply, “Just get rid of it.” While farmers have long known about the valuable nutrients

in manure, the main purpose of emptying the manure storage structure was often very simple — to make room for the next year. While we still need to clear out those pits and lagoons, over time, we have become much more particular about where those nutrients go. There are agronomic reasons: We want to target fields and crops that can make the best use of the nitrogen, phosphorus, and potassium found in manure. There are also economic benefits. The more nutrients that can be utilized from manure, the less money that will need to be spent on commercial fertilizers. And then there are the environmental implications. Putting manure where it can be used and will not become a source of runoff is better for us, for our neighbors, and for the world around us. Several articles in this issue focus on the nutrient content of manure and ways to deliver those nutrients to cropland. The area of manure management continues to grow with new technology to help us store, process, and utilize this resource. At the core, though, manure is an excellent nutrient source for our crops, plain and simple. Use the tools available to make these nutrients work for you. Summer is such a busy time of year for those in production agriculture, and this year, COVID-19 could make life even more challenging. Please be safe, stay healthy, and take pride in the essential work you are doing, day in and day out. Until next time,

Let us know your thoughts. Write Managing Editor Abby Bauer, 28 Milwaukee Ave. West, P.O. Box 801, Fort Atkinson, WI 53538; call: 920-563-5551; or email:

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MACROPORES CONTRIBUTE TO TILE FLOW These pathways may play a key role in tile drainage systems. by Eric Cooley


iscovery Farms is an on-farm water quality research and outreach program that is part of the UW-Madison Division of Extension. Tile drainage monitoring data collected on farms in Wisconsin has shown that macropores may play a key role in tile drainage systems. Macropores are preferential flow paths in the soil that can provide major transport pathways from the soil surface to tile drainage systems. Macropores can be formed by a variety of factors, including earthworm burrows, decayed root channels, shrinkage cracks, and the structural porosity of the soil. As observed when methylene blue dye is applied to the surface of the soil in Figure 1, the dye moved through the soil using a combination of macropores. Most of the dye entered the soil through shrinkage cracks in the soil surface, then moved laterally along the plow layer, and finally moved deeper in the soil profile through earthworm burrows. Water and nutrient transport through the soil matrix is much slower than through macropores, allowing for enhanced nutrient retention, whereas macropores can rapidly transport water and soluble nutrients to tile drains. The development of macropores in soil varies significantly with soil type and management. Soil that has been no-tilled long term typically has greater structural porosity, which supports macropore development. Earthworm

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activity also tends to be greater in no-till fields compared to fields that are annually tilled and can provide considerable macropore paths to tiles. Soils with higher clay content often develop large shrinkage cracks that occur as soil dries, and they can go deep into the soil profile. Nutrients and organic material from the soil surface can be transported rapidly through these shrinkage cracks, and if they intersect tile lines, can provide a direct conduit from the soil surface to the tile.

May increase tile flow Evidence of macropore flow to tile systems has been observed in two tile drainage studies with concurrent surface water runoff and tile flow monitoring in a basin. The first example is a long-term, no-till system where surface runoff during nonfrozen soil conditions rarely occurred, unless the tile system was flowing near maximum capacity. As shown in Figure 2, when a rain event occurred, there was often a rapid response in the tile system. This response was so rapid during intense rain events that tile flow was observed in less than 15 minutes from when the first raindrop fell. The combined macropore pathways of structural porosity and earthworm burrows in this no-till system provided rapid transfer of water from the soil surface to the tile system. Surface runoff didn’t initiate until the tile system was flowing near maximum capacity (see

dashed line in Figure 2). As tile flow began to subside below the maximum capacity, the surface runoff ceased. In this no-till system, phosphorus loss to the tile system was predominately in the dissolved form (77%) and was similar to surface water chemistry, indicating a strong link between the soil surface and tile system. If the flow was greater through the soil matrix, lower dissolved phosphorus in the tile would be observed. The second example is a conventional tillage system with macropore flow through a frozen soil. The winter of 2004 to 2005 was bitterly cold, with low snowfall through most of the winter. These factors drove frost deep into the soil. As snowmelt began in late March, there was still over 2 feet of frost in the soil. When daytime temperatures began

Figure 1. Methylene blue dye flowed through macropores in the soil (Shipitalo et al., 2004)

Open crack

Depth (feet) 0 Dyed crack face

Lateral movement zone

Dyed burrows



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More detailed information on understanding and managing tile drainage systems can be found at or

The author is co-director of the University of Wisconsin-Madison Division of Extension Discovery Farms Program.


0.3 0.25

Tiles flowing at capacity






0.1 0.05

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Surface Tile Rain

Hourly precipitation, in inches

Discharge, gallons/second (5-minute intervals)


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Figure 3. Surface runoff, tile flow, and snowmelt with conventional tillage 70

Surface runoff Tile flow Air temperature

3.0 2.5

60 50





30 / 3/

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Tile-drained agricultural land requires additional considerations when applying nutrients for crop production. The following are management considerations on tile-drained land with well-developed macropores. 1. Assess soil conditions prior to liquid manure applications. Both high and low soil moisture can be problematic for liquid manure applications to tile-drained land. Flowing tiles are often a good indicator of high soil moisture conditions, and well-developed soil surface cracks are an indicator of low soil moisture conditions. Manure applications should be avoided during high soil moisture conditions. During dry soil conditions with surface cracks apparent in the soil, either utilize pretillage before a manure application or reduce the initial application rate to slowly add moisture to the soil to facilitate closing of the cracks. 2. Review forecasted weather and avoid applications when rainfall is predicted to occur soon after application. Soil moisture levels are elevated by liquid manure applications and subsequent rainfall can result in tile flow and

manure injection depth should be used to prevent manure entry to tile drains. 6. Take precautions when surface applying liquid manure to no-till or perennial crops. Preferential flow paths are more developed in no-till systems and in later years of perennial crops. Split applications or reduced rates should be considered for liquid manure. â–

Figure 2. Surface runoff, tile flow, and precipitation in a no-till system

Discharge, cubic feet/second

Prevent nutrient loss

release of manure to tile drains. 3. Monitor tile outlets before, during, and after liquid manure applications for potential discharge of manure. Tiles flowing before applications are an indication of high soil moisture conditions, in most circumstances, and applications should be avoided. 4. Restrict tile discharge prior to manure application, if able. If water level control structures are installed in tile systems, insert stop logs to prevent flow from tile drains before application. 5. Use tillage to break up preferential flow paths prior to or concurrent with application. Pretillage for surface and injected liquid manure applications or application methods that concurrently disrupt preferential flow paths below the

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to rise above freezing (32°F) during the day and drop below freezing at night, flow was observed in the tile 24 to 48 hours prior to enough snowmelt water accumulating to result in surface water runoff seen in Figure 3. It is hypothesized that ice plugs that form in the macropores melt with a combination of the warming soil surface and warmth from the heat coming up through the soil from the tile system. Macropore flow to tile systems also happens by the daily cyclic heating of the soil and resulting tile flow, even when the soil matrix is frozen to a depth of over 2 feet. The chemical analysis of the water in both surface runoff and tile drainage were nearly identical for the monitored constituents. Both factors indicate a strong link between the soil surface and the tile, which are indicative of macropore flow.

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WYOMING The Laramie County Board of Commissioners voted to ease up on a long-standing requirement for Concentrated Animal Feeding Operations (CAFO). Previously, CAFOs wanting to locate in the Wyoming county had to get permission from all landowners within a three-mile radius of their farm. Now, after months of debate, it has been decided that any CAFO looking to build in the county will only need permission from neighbors within a one-mile radius. This change matches the current state statute.

the requirement in NR 151.07 to comply with a NMP during the emergency if a farmer demonstrates to the DNR that they do not have sufficient available storage capacity for unused milk and cannot comply with their current NMP when land-applying the milk. The agencies did indicate that these emergency actions should not cause an unpermitted discharge of pollutants to waters of the state. More information about land-applying milk can be found on page 9.



WISCONSIN Some dairy farmers have been asked by their dairy processor to dispose of, or dump, milk as a result of disruptions in the milk processing chain. This milk often ends up in manure storage structures and is eventually land-applied. In Wisconsin, the Department of Agriculture, Trade, and Consumer Protection (DATCP) and the Department of Natural Resources (DNR) offered the following to assist dairy farmers during this emergency: For permitted CAFOs, on a case-by-case basis, DNR can reduce the number of days required for public comment for modifications to a nutrient management plan (NMP), such as adding fields, which will allow CAFOs flexibility to quickly change their land application plans if necessary. For non-permitted farms, DATCP staff will assist with updating NMPs at no cost. If staff are not able to assist directly, DATCP will determine how to get help with updates to NMPs and the best way to assist with any cost. For non-permitted farms, the Governor’s Emergency Order No. 17 suspends 8 | Journal of Nutrient Management | May 2020

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renewable fuel. This renewable natural gas offloading station is the first of its kind in the nation. A station such as this gives biogas producers greater access to the pipeline.

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) issued a revised general permit for Concentrated Animal Feeding Operations (CAFOs). The start date of the permit is April 1, but EGLE planned to delay issuing Certificates of Coverage to the state’s 260 permitted farms for 60 days due to the COVID-19 pandemic. One notable change is that manure cannot be applied to farm fields in January, February, or March when the ground is typically frozen and runoff is more likely. Manure transportation is allowed during those months as long as it is not land-applied.

WISCONSIN A renewable natural gas offloading station at the Dane County, Wis., landfill received its first load of biogas in midApril. The biogas comes from a digester that converts manure and other substrates into methane. Once the biogas reaches the landfill, it is injected into the interstate transmission pipeline to be used as

The Swedish city of Lund used manure as a way to encourage social distancing amid the COVID-19 pandemic. City workers applied 2,204 pounds of chicken manure across the city’s main park as fertilizer to discourage groups from congregating during a public holiday. The nation has banned gatherings of more than 50 people, so city officials hoped that the smell of the poultry litter would keep people from visiting the park.

UNITED STATES The American Society of Agricultural and Biological Engineers (ASABE) has revised its standard for operating mobile liquid and slurry tanks. The standard, ASAE S317.1 JAN2020 “Improving Safety on Enclosed Mobile Tanks for Transporting and Spreading Agricultural Liquids and Slurry,” provides a guide for uniform practice and is intended to reduce risk of personal and public injury during normal servicing and operation of enclosed mobile tanks for transporting and spreading liquids and slurry. Originally developed in 1968, the revision updated key reference documents and made clarifications within the standard.

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n the depths of the COVID-19 pandemic and with people across the country sheltering in place, there have been some disruptions to our supply chain, from toilet paper to food products. Dairy producers have been hit especially hard, as milk destined for schools and restaurants suddenly had no place to go. Some farms received notices from their milk processing plants to slow production or to dispose of (dump) milk. In an attempt to salvage some value from dumped milk, the University of Wisconsin-Madison Division of Extension released some fact sheets with options for using this product. In one fact sheet, Carrie Laboski, Jamie Patton, and Kevin Shelly from the Nutrient and Pest Management Program discussed landspreading milk or milk and manure mixtures. They shared that, on average, 1,000 gallons of milk contains 46 pounds of nitrogen (N), 26 pounds of phosphorus (P 2O5), and 17 pounds of potassium (K 2O). When compared to liquid dairy manure, milk has six times more available N, nine times more available P 2O5, and one and a half times more available K 2O. Additionally, milk has a biochemical oxygen demand (BOD) around five times greater than dairy slurry. Consult your nutrient management plan to identify fields where milk can be applied safely. Choose fields with a low risk of nutrient loss through leaching, runoff, and erosion, and apply as close as possible to when crop nutrient uptake will occur. Avoid spreading on fields with sandy or loamy sand soil textures or soils shallow to bedrock. Steer clear of fields with tile drainage or those near streams, rivers, lakes, wetlands, drainage ditches, or wells. Once the proper fields are selected, apply milk uniformly across a field utilizing liquid manure equipment. When possible, the milk should be shallow-injected or incorporated to reduce the runoff risk and mitigate odors. More guidelines for application and recommendations for specific crops can be found in the fact sheet, which is available at The authors also noted that if milk is added to a manure storage structure, it may raise the effluent’s nutrient concentration, which would require an adjustment of nutrient crediting in a nutrient management plan. They said a sample should be collected and analyzed before application.

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oes your manure storage lagoon seem to fill up faster than it used to? In a recent C.O.R.N. Newsletter produced by Ohio State University Extension, Aaron Wilson, Glen Arnold, and Jason Hartschuh addressed reasons why manure storages reach capacity sooner as they age. One cause is a trend toward more precipitation in certain areas of the country. In Ohio, for example, annual precipitation has risen 1.35 inches per decade since 1960. That equates to an extra 27,154 gallons of water per acre of surface area entering the lagoon each year. Another challenge is that lagoons collect more sediments over time. This is especially true for dairy operations using sand as bedding. There are options for completely removing these solids, but this is not a small job to undertake. Lastly, many farms grow over time and may be housing more animals than they were when the storage structure was initially built. Estimates for how much manure is produced by different species are listed in the table. If more storage space is needed, the authors provided a few options: 1. Consider expanding the current lagoon or digging an additional one. Before doing this, review any necessary permits and connect with local soil and water conservation offices for help with engineering and possible funding. 2. A satellite pond close to some crop land is another way to add storage. This could save travel time when hauling manure and improve efficiencies when weather conditions allow manure application. 3. Reach out to livestock facilities that are no longer in operation but still have manure storage. Work out an agreement with that farm owner; an example may be that the livestock owner gives the manure away and pays to haul it to the storage structure, while the structure owner pays the field application cost.

Manure produced by livestock species Species





Bred heifer



Beef finishing



Swine nursery



Swine finishing



Lactating cow

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Low disturbance application has benefits We can incorporate manure to capture nutrients without raising the risk of erosion. by Eric Young


illage and manure application are critical nutrient management aspects affecting crop yield potential, soil erosion, and nutrient loss risk. Besides raising erosion potential, tillage over time also influences soil organic carbon accumulation or loss, soil structure, compaction potential, and overall soil quality. Mitigating soil erosion makes economic and environmental sense because long-term erosion reduces crop yield potential and can contribute to impaired water quality when sediment and nutrients in runoff are transported to surface water. It is well established that reducing tillage decreases erosion, particularly on moderate to steeply sloping fields with high erodibility. In corn silage systems, tillage practices depend on climate, soil characteristics (texture, drainage, and slope), and other farm-specific factors. Individual farm tillage practices may also vary by specific fields/soil types, and over time depending on weather, crop rotations, and compaction. In cold climates with poorly drained soils, tillage helps dry surface soils, break up clods, relieve surface compaction, and prepare a consistent seed bed. While reduced tillage is possible on imperfectly drained soils, strict

no-tillage is more common on welldrained soils where aeration is not typically limiting.

Preparing for application Tillage sets the stage for manure management. In conventional systems, manure is typically broadcast on the surface and incorporated via a primary tillage tool, such as a chisel plow, or secondary tillage tool, like a disk, harrow, or field cultivator. While effective at reducing ammonia volatilization and surface runoff nutrient loss, tillage incorporation has higher erosion potential compared to lower disturbance application methods. In addition, some studies suggest that long-term reduced tillage should further cut back erosion/surface runoff due to greater water infiltration rates from repeated lack of tillage. Low disturbance manure application (LDMA) attempts to achieve the conservation and soil quality benefits of reduced tillage (lower erosion and soil disturbance) while conserving ammonia nitrogen and mitigating runoff nutrient loss potential in the way conventional tillage does. LDMA equipment is engineered to minimize horizontal soil shearing and disturbance, leave more crop residue on the surface, and place manure beneath the

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soil surface or encourage infiltration to enhance manure-soil interaction. LDMA has focused mainly on applying liquid manures. Commonly used LDMA implements include applying manure in bands (banding) with or without aeration (banding/aeration), sweep injection, shallow disk injection, and various drag hose systems. By definition, broadcast-surface application is low disturbance as it causes minimal disturbance during application; however, ammonia-nitrogen is rapidly lost without incorporation, and nitrogen (N), phosphorus (P), and other nutrients remain shallow and vulnerable to transport in surface water runoff.

For corn or hayfields LDMA can work in both corn and hay crop rotation phases. Previous research led by the USDA Agricultural Research Service (ARS) compared surface runoff water quality from corn-winter rye plots under the following treatments: 1. No manure (control) 2. Broadcast-surface application 3. Broadcast-disk incorporation 4. Banding/aeration 5. Sweep injection with strip till Results showed that strip till injection had 84% to 99% lower P losses compared to broadcast soon after fall manure application. Aeration/banding

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also reduced ammonium and dissolved P, but it was not as effective as strip till injection for total P and N, similar to the broadcast-disk treatment. Average runoff total P, dissolved reactive P, and ammonium-N concentrations did not differ statistically between strip till injection and the no-manure control, suggesting injection mitigated surface water quality risk more than the other methods for runoff events soon after manure application. Another important aspect highlighted by this study was runoff timing relative to manure application. In the two spring runoff events, total N and P concentrations dropped substantially compared to fall, with few significant differences between methods. Timing and method also affect the amount and distribution of soil nutrients and crop yield potential. While yield was not part of this study, a separate four-year ARS trial showed that fall-applied manure via strip till injection produced similar corn silage yields to spring-applied fertilizer N, indicating injection conserved more N compared to other application methods. A main concern with LDMA in hay crops is plant damage and yield loss. Encouragingly, studies in the U.S. and other countries report relatively low risk of stand injury under low application rates and done under proper conditions. In mixed alfalfa-grass plots in central Wisconsin, recent work led by ARS indicated that runoff total N and P for shallow disk injection was significantly lower than the aerator/ band treatment and similar to the no-manure treatment. Like broadcasting manure, LDMA after hay harvest is ideal before any regrowth occurs. Soil moisture status is an important factor to consider anytime manure is applied, and especially for LDMA. Studies indicate that banding/aeration on wet soils is ineffective and could even exacerbate runoff potential by causing compaction and reducing infiltration. Applying liquid dairy manure after hay cuttings is a common practice and

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provides an important source of N, P, sulfur, potassium, and other nutrients. However, without immediate injection or incorporation, greater than 80% of manure ammonia-N can be lost within 24 hours of application, reducing the agronomic value. While N loss from lack of incorporation may not be as much of a concern for more leguminous stands, nutrient loss risk is still worrisome since broadcast manure (liquid or semi-solid) is more vulnerable to runoff. Another consideration is P accumulation from repeated manure applications and lack of tillage to redistribute P. Depending on soil test P levels and runoff risk, P accumulation from LDMA may or may not be an issue.

Keep nutrients in place

Broadcasting without incorporation may seem faster and cheaper, but it may not be more cost effective when factoring in lost N. It is also a high water quality risk compared to incorporation. LDMA mitigates tillage-related erosion and leaves more residue compared to conventional tillage. Evaluating the suitability of LDMA must consider N savings and the lower environmental risk in addition to greater time, labor, and equipment needs. Future work should consider both economic and environmental aspects of LDMA to help farms determine their most efficient manure management strategies. ■

The author is a research soil scientist for the Institute for Environmentally Integrated Dairy Management, USDA-Agriculture Research Service.

The bottom line is that LDMA offers several agri-environmental advantages over broadcasting and/or broadcast-till.

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by Abby Bauer | Managing Editor

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estled in the foothills of central Georgia, the Cooley family raises chickens and crops on their farm near Roberta. While biosecurity concerns limit the opportunity for visitors on many poultry operations, the Cooleys have always valued consumer education. From their animal care to litter management, transparency and sustainability are permanent parts of their agriculture story. The Cooleys’ efforts were recognized nationally, as they were named USPOULTRY’s Family Farm Environmental Excellence Award winner in 2011. The award recognizes farms in poultry and egg production for exemplary environmental stewardship. Terri and Larry Cooley purchased the farm in 1985. A year later, they put up two chicken houses and then two more a few years later. They doubled in size to eight houses in 1995. After their son, Leighton, returned home from college in 2005, they built four more houses. Today, there are 16 broiler houses spread between three sites. Leighton is the second generation to own and operate Cooley Farms, but he is actually a fourth-generation poultry producer, as Terri’s grandfather and father were farmers, too. The Cooleys raise chickens for Perdue Farms. Their operation has capacity for 500,000 birds at one time. They raise six flocks per year, finishing about 3 million birds annually. In their relationship with Perdue, they receive chicks at one day of

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age. The Cooleys raise the birds for 42 days before they are shipped to Perdue’s facilities to be processed. Pay is determined based on an average price per pound of live weight, ranked against the weight and feed conversion rate of other farms selling birds that week. The Cooleys explained that there are three main components of a chicken house: temperature, water, and air. While those basics are still at the core, building design has advanced over the years. The Cooleys have made investments over time to improve their chicken houses, which are 45 feet wide by 600 feet long. “Technology in the poultry industry has made leaps and bounds,” Leighton said. For example, their tunnel-ventilated barns now pull air through cooling cells to help moderate the temperature in the barn during the long, hot Georgia summers. “In the summer, we used to see increased mortality (due to the heat), but now we see just a slight dip in performance,” Leighton said. “A comfortable chicken is going to be

a better growing chicken.” There are central controls for each house, and this information can be accessed on a computer, smartphone, or tablet. The Cooleys can get a live snapshot of what is going on in each barn at any moment. “We used to say we grew chickens by the day, but now we grow them by the minute,” Leighton said. Continuous access to feed, water, and fresh air is a necessity in a poultry barn, so every barn has a backup generator that takes over in a few sec-

The broiler houses are bedded with composted litter, which provides a soft base for the birds. onds if the power goes out. They also do a lot of preventative maintenance to keep everything up and running. Even with all the technology advancements, the Cooleys emphasized the important human element in raising chickens. “Technology doesn’t replace human interactions, it just enhances it,” Leighton said. Along with his parents, May 2020 | Journal of Nutrient Management | 13

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Leighton works daily with their crew of three full-time employees to care for their flock. They also raise 165 Angus beef cows and run 1,000 acres of hay land, pasture, and timber. Leighton’s wife, Brenda, and older sister, Amanda, work in education but return to the farm to help when needed, especially during the summer months. His younger sister, Courtney, and her husband, Jones, operate their own poultry, beef, and small grains farm.

The benefits of litter Much of the manure produced by their broilers is recycled and utilized as bedding, commonly known as litter. In fact, the Cooleys estimate that some of the composted litter in their barns is four years old. In between flocks of birds, each barn stands empty for two to three weeks. During that time, the floor is prepared for the next group of broilers. First, they use a decaker to sort out the wet litter or cake. The machine sifts and shakes the litter as it moves through the barn. The material that remains is placed into two three-foot tall windrows. After three days and two turns, those windrows reach a temperature of 130°F, which composts the litter. Then the litter is leveled throughout the barn. Additional shavings are added if needed, but Leighton noted the benefits of the litter buildup. “It makes a better base, and it provides natural immunity for young birds,” Leighton said. He also shared that the 5 inches of litter they provide as a base is better for the broilers’ feet and legs, which is very important when it comes to raising birds. A dry floor is key, as wet litter creates moisture and ammonia in the air. Their ventilation system can exhaust this out, and a poultry litter treatment to neutralize ammonia can be used if needed. Litter that leaves the barns is put under one of three stack barns. These are open-ended barns with concrete floors where manure is stacked and used or sold. Some of the manure is spread on their pastures and hayfields; the rest is sold by the ton and custom applied.

Any litter removed from their broiler houses is placed in one of three stack barns. The manure is stored here until it is used as a fertilizer source or sold. Their pastures receive litter exclusively, but forage fields will be supplemented with some commercial fertilizer as needed. The Cooleys test their litter annually, and they said the nutrient content stays pretty consistent.

Better than ever

Poultry manure is high in nitrogen and phosphorus, so it is a useful fertilizer, when applied appropriately. Since 2011, the Cooleys have used GPS to apply litter to their land. “There are a lot of variables in manure spreading,” Leighton said. “We wanted to add consistency to something that can sometimes be inconsistent, and using GPS was something we could control.” The Cooleys have a nutrient management plan for each of their farms, and they have improved their record keeping over time, documenting how much they were applying, where, and when. They also look for opportunities to do better. “We try to stay educated on practices we should or should not do,” Leighton said. The Cooleys’ stewardship goals are very personal, as they want to see their land flourish in the future for Larry and Terri’s nine grandchildren, who love being on the farm. “The farm is in better shape, by leaps and bounds, than when Mom and Dad

14 | Journal of Nutrient Management | May 2020

F3 12-15 Q2 2020 Farm Story.indd 14

Larry, Terri, and Leighton Cooley stand in their farm’s educational center, which includes viewing windows so that visitors can look into one of their broiler houses. moved here in 1985,” Leighton said. “That’s our vision of sustainability; not only leaving everything better than when we found it, but offering an opportunity for the future.”

From the inside out

The Cooley family has offered tours of their farm for the past three decades, but after visiting Hayden Farms, an

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operation in Kentucky that had a viewing area in one of their broiler houses, Terri wanted to do more to enhance the educational experience on their farm. She started doing research and presented the idea of incorporating an educational center on the farm to Larry and Leighton. “We all understand the importance of educating and advocating about agriculture,” she explained. “Poultry farms are hard to see for biosecurity reasons. It’s difficult to introduce consumers to chicken houses, and that leads to misconceptions.” Once the family agreed to venture down this path, the Cooleys built a 20-by-30-foot room with floor-to-ceiling windows in one of their poultry houses. They made the educational center look like a real chicken house, with waterers, feed lines, and so forth. The educational center officially opened in October 2019 with a grand

opening celebration, and since then they’ve hosted school field trips, legislators, bloggers, and others for tours. “Transparency is really important to us,” Terri said. “We think there is a need to let people see what we do.” Another unique opportunity to teach about agriculture presented itself to Leighton a few years ago. Their stewardship practices caught the attention of producers working on a documentary called “Farmland.” They were looking for six young farmers and ranchers around the country to share their experiences and talk about modern agriculture. Leighton talked to his family first and then eagerly accepted the opportunity. “We are always willing to open our doors to share our story and the pride we take in producing food.” He was very pleased how the film turned out and for the chance to promote agriculture on a national stage.

“It was a really cool experience,” he said. “It was an opportunity we never saw coming to share our story.” Beyond education, being a good neighbor is also very important to the Cooley family. “We try to be careful and be the best neighbors we can be,” Leighton said. Terri added, “We have been part of this community for 40 years. We take what our neighbors think of us seriously, because we live here, too. We are very fortunate to live in this community.” Farming in the hot climate of Georgia just 70 miles from Atlanta brings its challenges, but the Cooleys are thankful to pursue their agricultural passions on the farm Larry and Terri started 35 years ago. While incorporating technology helps them better care for their animals and the land, it’s the human element in both raising broilers and communicating with the public that the Cooleys value most. ■





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May 2020 | Journal of Nutrient Management | 15

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Changing manure composition with diets Rations formulated to specifically meet an animal’s needs will reduce the amount of nutrients lost through manure. by Joe Harrison


eed represents the largest import of nutrients to most livestock and poultry farms, followed by commercial fertilizer. Feed management opportunities exist to reduce imports of nutrients, particularly nitrogen and phosphorus, to most livestock operations. The technologies and approaches to achieve these reductions vary in their degree of economic feasibility and environmental impact. In 2006, a feed management education project was implemented for beef, dairy, poultry, and swine. The project was national in scope and designed to encourage adoption of the Natural Resources Conservation Service (NRCS) Feed Management Conservation Practice Standard 592 and feed management practices that can have a positive impact on soil and water. Detailed information can be found at

Reduce nutrient imports Feed management is one of six core elements in a Comprehensive Nutrient Management Plan (CNMP). The initial activity associated with the development of a feed management plan is to conduct an on-farm checklist designed to identify those practices that will most likely reduce imports of nutrients and/or improve profitability. The most common practices that can

reduce imported feed nutrients on the farm include: • Diet formulation to meet the requirements of the animal • Feeding animals in groups • Regularly analyzing ingredients or diets for nutrient content • Formulating livestock diets for protein fractions • Utilizing growth promotants and ionophores • Using enzymes Once it has been determined that a feed management plan is a good decision for a farm, a feed management plan checklist is then utilized to collect information that will be used to complete the plan. Categories of items in the feed management plan checklist are: • Targeting nutrient requirements • Ration balancing • Ration management practices • Production aids/enhancers • Monitoring tools The feed management plan template is designed to outline and document the practices that will assist with minimizing the import of feed nutrients to the farm. In addition, it is designed to create a “live” document to use in strategic and tactical planning. Special attention is given to sampling frequency, analysis of specific nutrients, specific recommendations on practices to adopt, how the feed management plan will change the

16 | Journal of Nutrient Management | May 2020

F3 16-17 Q2 2020 Diets.indd 2

nutrient composition of manure, and specific review dates. An intermediary step in the implementation of a Feed Management Plan that will be considered by some livestock and poultry operations is the economic evaluation of the choice to make ration changes or transport manure a farther distance. What follows are some dairy specific nutrient reduction opportunities.

Feed for reduced crude protein The transition from feeding the dairy cow for its crude protein requirement has clearly progressed today to a more sophisticated approach of formulating for the estimated requirement of amino acids. While this transition has been occurring, there has been a simultaneous progression for a greater awareness of the interrelationship of diet formulation and feed management on whole farm nutrient oversight.

Amino acid formulation Amino acid formulation for dairy cattle has been a common practice since the availability of the Cornell Net Carbohydrate and Protein System model and the Cornell-Penn-Miner model. Both models have been used successfully to strategically formulate diets to evaluate the merits of sources of ruminally undegraded protein (RUP), ruminally protected amino acids, and

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free lysine-HCL. Other researchers have had positive experiences with use of the model to formulate diets to reduce the crude protein (CP) level in the diet while maintaining milk production. Other studies I conducted continue to provide evidence that formulating diets for available amino acids can provide the opportunity to lower CP levels in the diet and reduce the on-farm import of nitrogen. A field study was done with a high-producing herd to compare their general herd diet formulated at approximately 18% CP to a diet that was reformulated at around 17% CP. Results showed that milk production could be maintained while reducing nitrogen import to the farm (Tables 1 and 2). In addition, the diet reformulation resulted in an improvement in income over feed cost (IOFC), as shown in Table 3.

through urine and manure without negatively impacting cow productivity. Farms should take a close look at their feed management plan and determine areas where nutrient losses can be minimized. There are environmental and financial benefits to be gained. â–

Another experiment conducted with lactating dairy cows assigned to recommended (0.37% of DM) or excess (0.57% of DM) dietary P. Cows were fed the respective diets after calving and reproductive parameters were monitored. The authors concluded that feeding P in excess of NRC (2001) requirements (0.37% of DM for the cows involved in this trial) did not improve reproductive performance. These studies and others indicate that diet adjustments can be made to reduce the amount of P lost

The author is a professor and nutrient management specialist at Washington State University.

Table 1. Treatment response to diet reformulation Control




DM intake, lb






CP intake, lb





Milk, lb





3.5% FCM, lb





The phosphorus feeding myth

Fat, %





A major reason for overfeeding P to dairy cows is concerns related to reproductive efficiency. Past research has related P deficiency to health and reproductive problems, including failure to conceive and reduced calving rates. Extensive reviews on the topic have been published. In retrospect, it appears that low P intake was linked to impaired reproductive performance in cattle through a series of confounded and misinterpreted experimental data reported in the late 1920s through the 1950s. A summary of 13 trials with lactating dairy cows (392 to 393 cows) and heifers (116 to 123 heifers) showed no effect of dietary P on reproductive performance. Levels of P in the cow diets varied from 0.32% to 0.40% (low-P groups) and from 0.39% to 0.61% (high-P groups) of dry matter (DM). Heifers were fed 0.14% to 0.22% and 0.32% to 0.36% dietary P, respectively. Days to first estrus, days open, services per conception, days to first artificial insemination, and pregnancy rates were not different between the low- and high-P cows. Similarly, services per conception and pregnancy rates were not affected by dietary P level in the heifer groups.

Milkfat, lb





Protein, %





Milk protein, lb





F3 16-17 Q2 2020 Diets.indd 3

Milk urea nitrogen, mg/dL





Ratio milk true protein: Intake protein ratio





Body weight (BW), lb









Change in BW, lb Source: Harrison et al., 2002

Table 2. Environmental characterization Item



% Change

Nitrogen intake, gms/d




Milk total N, gms/d*




Predicted urinary N, gms/d**




Calculated fecal N, gms/d***




*(Milk true protein - gms/6.38) X 1.17 **Estimated per J Dairy Sci.85:227-233. Urinary nitrogen (gm/d) = 0.026 X BW (kg) X MUN (mg/dL) ***Intake N- Milk N- Urine N Source: Harrison et al., 2002

Table 3. Economic evaluation Control


Feed costs, $/day/cow




Milk income, $/day/cow





IOFC*, $/day/cow

*IOFC = Income over feed cost; Source: Harrison et al., 2002

May 2020 | Journal of Nutrient Management | 17

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Sample before you spread T

While storage structures vary, the keys to good manure sampling are fairly consistent. by Liz Matzke

aking samples is an essential step to appropriately apply manure to fields. However, getting an accurate sample of nutrients across livestock systems and differing storages can be challenging. What follows are guidelines for the best practices for manure sampling from various storage systems. They come from a Livestock and Poultry Environmental Learning Community webinar titled “Manure sampling considerations in different animal production systems.” It is important to remember that guidelines may vary from state to state, so check with your local regulatory agency.

Working with solids For stockpiled manure, sampling before spreading or during spreading both have advantages and drawbacks. When you sample prior to spreading, that information can help determine application rates; however, it can be more difficult to get a good representative sample. Additionally, samples taken ahead of time may not reflect what is actually applied to fields. Depending on when the samples are taken and the processing time, there can be additional rainwater and manure added to the pile. To avoid this, many choose to sample during the application process. This

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F3 18-19 Q2 2020 Sample.indd 1

does provide the most accurate sample, but usually the information is received too late to change application rates. Aaron Nygren, University of NebraskaLincoln, suggested, “If you are unable to receive samples back in time for application, you can rely on a five-year average from your farm. Keep in mind, though, that samples can still vary greatly.” Time of year, animals’ diets, weather, and storage management can all impact nutrient value of manure. Since this is the case, it is imperative to take numerous samples. “The more we do, the better,” Nygren said. It has to be realistic, though. Nygren recommended that you collect 15 or more samples, and that your samples come from at least six inches deep. If your piles are larger, an auger can be helpful to reach various depths. If samples are being taken from scrapings in an open lot, take at least 20 samples, and avoid collecting too much dirt. Whether sampling solid or liquid manure, Nygren noted, “Remember how variable the manure can be. That is why proper sampling technique is important.” Once the samples are collected, they should be mixed well, and an overall sample should be taken quickly. This is particularly important for liquid manure samples, as it avoids the separation of solids that begins almost immediately.

Try to record your method of sampling. “Whatever you do, write down that protocol, because we want to be consistent from year to year,” Nygren said. “If I grab it one way, one year, and a totally different way the next year, differences in the tests are as likely to be from the sampling method as it was from the samples themselves.” When it comes to manure removed from a barn, Nygren said that sampling location didn’t matter, but consistency of when and where samples were taken year after year was again king. What is analyzed will differ from state to state and laboratory to laboratory, but Nygren recommended that farmers test for the following: • Total nitrogen content • Ammonium nitrogen • Nitrate-nitrogen • Phosphorus • Potassium • Zinc • Sulfur • Soluble salts • Moisture content • pH

It’s not easy With all the factors that influence the physical and chemical makeup of manure and its nutrients, sampling

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really provides a complete picture of what is being added to your fields. Equally as important is the application rate of manure, which can be impacted by more than the manure itself. Time, labor, facility design, and equipment all play a role in spreading. Karl Vandevender, University of Arkansas, explained that for these reasons, sampling gives the most “meaningful values.” “Nitrogen tends to be very homogeneous in a pond, but phosphorus generally settles on the bottom,” commented Vandevender. “This information can be used to customize spreading from field to field.” Holding ponds are approximately 8 feet deep, with less than 1% of the solids in the top layer of the pond and as much as 14% at the bottom of the pond. Knowing this can impact how you sample from the pond. If agitating the pond, try to pull samples from each layer (top, middle, and bottom) and then mix the subsamples together. If the pond isn’t agitated, collect from the zone you’ll be spreading from. It is recommended to take at least eight samples. Again, collect the overall sample as quickly as possible to avoid separation. When filling the final sample container, make sure to fill it only about half full. An air pocket is needed to help avoid the sample “exploding” during transport, Vandevender said. Something as simple as a bucket at the end of stick can be used when collecting subsamples. However, Vandevender recommended using a 10-foot long PVC pipe with a stop ball at end of it. This way, you can collect from all layers as you move the pipe down through the pond, filling the inside of the PVC tube. Vandervender commented on the difficulty of taking manure samples. “Manure varies every time you turn around,” he said. “Perfect sampling is unachievable, but good sampling is a process that can get better over time. Do the best you can and acknowledge there are opportunities for improvements in the future.”

In Rice’s experience, this is sufficient for sampling purposes. Rice also touched on sampling litter from poultry barns. If sampling before the barn is cleaned out, take samples from a cross section of the barn to get a representative final sample. If collecting after the manure has been removed from the barn and stockpiled, Rice said to refer to the solid manure sampling guidelines mentioned earlier. And for all manure types, refrigerate samples as soon as possible following collection, Rice advised.

Do it right There will always be variation between samples, and there will be outlier samples as well. Understanding this is helpful when planning and applying manure. “The key is to have a good representative sample,” Nygren reiterated. “A sample is only as good as the time you put into getting it.” ■

The author is a freelance writer from Monroe, Wis. She owns Denim Works LLC.

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Emptying the lagoon While holding ponds and lagoons are similar, there are some subtle differences when sampling. “When irrigating the whole lagoon at one time, be sure to sample all the layers in the lagoon, including all of the water layers and the bottom sludge layer,” recommended Mark Rice, North Carolina State University. There is a tool called the Sludge Judge that can be used to sample, but similar devices work as well. Infrared sensors can help to measure the density of the sludge layer, or fish finders can be used to identify the active part of the sludge layer. It not recommended take a boat on to the lagoon, Rice said, to do this testing. “Safety is always a concern,” he explained. There are GPS boats that exist for this task. These devices can record depths, focus on where to sample, make sludge maps, and more. Sludge maps are key as the bottom sludge layer can change drastically from month to month. When sampling lagoons with covers, Rice noted that very little changes in technique. Most covers have four 24-inch openings.

F3 18-19 Q2 2020 Sample.indd 2

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May 2020 | Journal of Nutrient Management | 19

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Up to growth stage V4, growing corn can be sidedressed with manure without causing damage and impacting yield.

WIDEN THE MANURE APPLICATION WINDOW Sidedressing growing corn with manure is an opportunity to get more nutrients out to the fields. by Amber O’Brien


ith the extreme weather events in recent years, dairy farmers in certain parts of the country have had a difficult time emptying their manure pits before the winter freeze. Continuous rainfall during the critical weeks of planting and harvest has been a common trend in some areas.

A race against time Corn silage is the number one ingredient in most dairy herd diets. In the fall, a large amount of liquid dairy manure is applied to these harvested corn silage fields. In the Upper Midwest, harvest typically begins in early September, or late August in the

occasional dry year. However, latespring planting and heavy rains in August and September 2019 pushed back harvest start dates, resulting in delayed manure application. A substantial amount of manure needs to be spread during this shortened time period between harvest and winter. Due to a combination of saturated soils and heavy manure application, there has been an elevated number of manure spills and runoff incidents. This has created surface and potentially groundwater quality contamination. A study conducted in the Upper Midwest by UW-Discovery Farms and collaborators assessed monthly nitrogen loss to tile drains of fall applied

20 | Journal of Nutrient Management | May 2020

F3 20-21 Q2 2020 APPL Window.indd 2

manure compared to spring applied manure. The soil types and application rates varied between the multiple test sites, but the average total nitrogen loss for one year of fall applied manure was 48 pounds per acre, while the spring applied manure averaged a loss of 26 pounds per acre.

Consider other options Because of this reoccurring issue, dairy farmers will have to consider other options to widen the window for manure application. Cropping systems may have to change, such as planting shorter maturity corn for an earlier harvest or planting alternative forages that allow for manure to be applied

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Table 2. Drag hose damage to corn plots, 2014 to 2018 Year






Corn stage

Stand (bu)

Yield (bu/ac)

Stand (bu)

Yield (bu/ac)

Stand (bu)

Yield (bu/ac)

Stand (bu)

Yield (bu/ac)

Stand (bu)

Yield (bu/ac)

Fiveyear ave.

No drag hose








































































Source: Ohio State University College of Food, Agricultural, and Environmental Sciences

throughout the year. Applying manure to a growing corn crop is another option. This strategy not only relieves manure storage capacity, but it can be utilized as a great source of nutrients for growing corn. Ohio State University Field Specialist Glen Arnold has conducted research on multiple aspects of applying manure to growing corn. One project looked at drag hose application methods and evaluated which growth stage of corn can receive the application without yield loss. After reviewing the results over a five-year trial, Arnold stated “corn could be sidedressed with liquid livestock manure using a drag hose up to growth stage V4 without a yield loss.” By V5 stage, over half of the stalks were snapped and did not produce a high-yielding crop. See Table 2 for details. When applied at stage V3 (manure tested to meet nitrogen needs), the sidedressed-incorporated dairy manure yielded higher than the 28% urea ammonium nitrate (UAN) plots and surface applied manure plots. More information on OSU Extension’s manure sidedress research can be found at:

Working with growing corn Extension in Calumet County brought this idea to Wisconsin and collaborated with industry partners to analyze various techniques to sidedress manure to a corn crop at growth stage V2 to V3. This included: 1) dragline at a traditional angle with a splash pan; 2)

F3 20-21 Q2 2020 APPL Window.indd 3

dragline at a traditional angle with a dribble bar; 3) dragline with the rows with an incorporating toolbar; 4) incorporation with tractor tanker; and 5) dribble application with an Agrometer. More details of this on-farm trial can be found at Farmers who consider utilizing manure on their V1 to V4 stage cornfields should acknowledge that there are soil and weather conditions that can play a role in yield results. A firm seedbed can be created with cover crops and no-tilled soil, which is ideal for dragging hose over corn. If the field is saturated from a recent rainfall, the drag hose may pull the corn stalks out of the soil. Dry matter content in the manure should also be considered. Thick manure, surface-applied at a heavy rate, followed by no precipitation, could potentially burn the corn crop. There is also the possibility of losing available nitrogen when manure is surface-applied as opposed to incorporated, as it can volatilize from the surface. Other variables such as the type of tire to use while applying the manure and the size of a drag hose should be noted. Farmers and manure applicators potentially have a win-win situation with this strategy of growing-crop manure application. It gives them an extra opportunity to apply manure to a crop that can utilize its nutrients at the time it needs it most, during the growing season. Farms may be able to reduce synthetic fertilizer expenses if they can use manure as their main source of

nitrogen. Finally, many nutrient management plans allow for more gallons of manure to be applied to a field if there is an established growing crop. ■ The author is the Calumet County agriculture educator for University of WisconsinMadison Division of Extension.

May 2020 | Journal of Nutrient Management | 21

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Manure’s contribution to carbon footprints The storage and removal method of manure can significantly alter a swine farm’s environmental impact. by Erin Cortus

n environmental footprint is one metric to understand the impact of current production practices. Diving deeper into what composes the footprint gives an operation the power to identify strategies to change the shape of the footprint in the future. Remember, though, that a footprint is only one metric, one number, one part, of all the considerations a farm should include in their environmental stewardship. Simplistically, a carbon footprint represents, in units of carbon dioxide, the amount of greenhouse gases (GHG) generated during production.

ducer-supplied information to calculate farm-specific carbon, water, and land footprints from cradle-to-farm gate. Cradle-to-plate: This includes cradleto-farm gate GHG emissions plus GHG emissions generated during pork processing, delivery to stores, and preparation by consumers. An example of cradle-to-plate footprints in action is the National Pork Board’s recent report showing carbon emissions per pound of pork produced declined 55% over the last 55 years. We recently worked with pig farmers in Minnesota, Nebraska, Iowa, and South Dakota to calculate carbon footprints for their farms using the Pig

Greenhouse gas emissions ÷ Unit of production = Carbon footprint

Figure 1: Type of manure management system Pounds of carbon dioxide equivalent per pound of pig at farm gate

Before taking a footprint at face value or comparing two footprint numbers, recognize that scope and unit of production dramatically affect a footprint result. The scope, or boundary, makes a big difference! The scope of the footprint outlines what part of the production cycle is included in the calculation. For pigs, two common scopes are: Cradle-to-farm gate: This includes GHG emissions generated during feed production, operating barns, and managing animals and manure to support a pig through its growth until the pig leaves the farm. The Pig Production Environmental Footprint Calculator (available at uses pro-

3.5 Other, 0.06

3.0 2.5

Other, 0.05

2.0 1.5

Manure management, 1.26

Manure management, 1.79

Other, 0.03 Manure management, 0.66

1.0 0.5

Feed, 1.18

Feed, 1.18

Feed, 1.18

Deep pit

Lagoon storage



Carbon footprints for a sample farm simulated with either a deep pit, lagoon storage, or digester manure management system.

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F2 22-23 Q2 2020 Carbon footprints.indd 1

Production Environmental Footprint Calculator. When we used a common corn and soybean meal-based diet for all farms, the range of footprints for the wean-to-finish barns was 2.37 to 2.54 pounds carbon dioxide equivalent (CO2e) per pound of pig at the farm gate, and 1.60 to 2.50 pounds CO2e per pound of pig for grow-to-finish barns. Wean-to-finish barns raise pigs from newly weaned (approximately 15 pounds) to market weight (approximately 285 pounds). Grow-to-finish barns raise pigs starting at 50 pounds to market weight. All of the participating wean-to-finish and grow-to-finish farms in our

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study had deep pit storage of manure under the slatted floors of their barns. For these farms, the two main contributors to the cradle-to-farm gate footprints were feed production (48%) and manure management (49%). Feed production includes the energy consumed in the production of fertilizer and crop inputs, field activities, harvesting and processing of feed ingredients, as well as emissions from the soil system. Energy use in this chain generally relies on fossil fuel use and releases greenhouse gases. Electricity, barn heat, and water distribution were generally less than 3% of the footprints.

The role of manure The GHG emissions from manure are methane and nitrous oxide. Methane formed is from the anaerobic breakdown of manure organic material. Higher temperatures and a longer storage time raise the rate of methane generation. There is an optimum amount of organic material — the volatile solids portion of the manure — for methane generation. Too little and there is not enough food for the anaerobic microbes. Too much and the microbes are overwhelmed. Nitrous oxide production depends on the nitrogen content of the manure. The type of manure storage influences both methane and nitrous oxide emission. Because the manure storage system contributes almost half of the GHG in a cradle-to-farm gate carbon footprint, changing the storage method and removal frequency can significantly alter a farm’s carbon footprint. We used an example grow-to-finish farm in Nebraska and the Pig Production Environmental Footprint Calculator to show how the carbon footprint changes when we simulate a farm with deep pit storage, lagoon storage, or an anaerobic digester (covered lagoon with electricity generation; Figure 1). A properly designed and managed lagoon system degrades and stabilizes organic matter, producing methane in the process. Nitrous oxide is a product of incomplete nitrification and occurs in anaerobic conditions. Methane is also produced by deep pit manure storages, but the anaerobic decomposition process is hampered by higher nutrient concentrations; thus, there are lower methane and nitrous oxide emissions. A digester promotes anaerobic stabilization of manure, but the methane is captured and a portion of the methane is converted to other forms. While a change in manure storage design has carbon footprint implications, one must also consider local regulations, climate, cost, and both indoor and outdoor environments. There are advantages and disadvantages to all storage systems. Earthen manure storages are not as common (and sometimes not allowed for pig farms) as deep-pit systems in Minnesota and other regions. Lagoon systems are more prevalent as you move south where warmer weather is more conducive to maintaining sufficient biological activity for manure treatment purposes.

contribution of manure by 36% and the farm’s overall carbon footprint by 18%. Responsible manure management requires applying the manure nutrients when the crop can use them, but also lowering the risk of nutrient losses to the environment. In Northern regions, fall application after harvest of crops, when cooler soil conditions reduce volatilization losses, is a best management practice to limit the risk of nutrient loss. Spring application of manure prior to planting situates the manure nutrients in place immediately before use by a growing crop. However, many farmers try to avoid spring application to minimize compaction of wet soils by heavy manure application equipment. Carbon footprints are popular metrics in sustainability discussions, on and off the farm. Knowing the scope of a footprint and the major components that make it up lead to strategies to reduce the footprint value. However, the footprint needs to be part of a larger conversation about priorities and trade-offs in decision-making. ■

The author is an assistant professor and extension specialist of bioproducts and biosystems engineering at the University of Minnesota.

Empty more often Using the calculator, going from once per year to twice per year manure removal from a deep pit manure storage system on a typical grow-to-finish farm reduced the carbon footprint

F2 22-23 Q2 2020 Carbon footprints.indd 2

May 2020 | Journal of Nutrient Management | 23

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READY TO ROLL Maintenance work takes time and effort, but these essential tasks set us up for a successful spring. by Jesse Dvorachek


t has been a productive couple months. We finished our pumping season on January 7 and went right into maintenance season. We had to, since our time for repairs was shortened a whole month because of the wet and late fall. My team jumped into changing oil, filters, and cleaning tractors like we never have before. This year I had my staff remove all the tires, rims, and weights from the tractors to try to get every last piece of mud hiding under cabs and on top of the axles. It’s amazing what you can find hidden behind wheels and tires. I think we are going to add this practice to our maintenance program every year. Once the easy stuff was done, we took all our tractors to our local dealer for their regular winter maintenance. While the tractors were gone, we pulled pumps in to the shop and started dismantling the plumbing for their winter inspections. We like to check them every year just to make sure there is no odd wear going on, or to see if there is a potential problem we can catch before a major malfunction occurs. As all of this is going on, other guys are still washing what’s left of the hose carts and tanker so we can start inspections on them. We go through all our dumpster hinges to make sure the hoses in them have no leaks. We also make sure all our lights on our dumpsters are in working order. This last year we welded some holders to the dumpsters to keep cleanup

As custom haulers, we all want our team to be as professional as possible, and I think this training helps them to think a little more like I do. tools like scrapers and shovels. It’s been a nice addition because people on-site can start cleanup as soon as we are done pumping. They don’t have to wait for the service truck to arrive with helpers to move equipment to the next field. One project that always seems to take a couple days is cleaning and reorganizing our service vehicles. During the fall rush, things always get jumbled around, and items need to be reorganized and restocked. Having a couple service bodies with bins for parts inside each vehicle has been a very nice addition that our crew leaders have come to appreciate. The ability to stock their trucks with most of the items they will need in the field has saved a lot of down time from running for parts. Those service bodies are not cheap to add to the service vehicles. I struggled buying them in the beginning, but now that I have seen how they can save us time, it’s not such a hard pill to swallow. Lastly, our favorite job of the winter is going through our 20-plus trailers. We send them across the street to a neighboring truck repair shop, and they give us a list of things to fix so they can give us the Department of Transportation (DOT) stickers we need to run them legally down the road. That has become a practice that has worked very well

24 | Journal of Nutrient Management | May 2020

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for us. We don’t have a certified guy in the shop, but I have plenty of employees who know how to use a wrench. Once all the trailers are done, we start on new projects for the year and tie up any loose ends that we need to have done before the spring rush. In the winter, I also like to attend meetings and send all my employees to trainings that are available to us through educational venues such as University of Wisconsin-Extension. I think it helps my guys understand a little more about what’s going on around them and feel like they are not just a warm body in a seat. As custom haulers, we all want our team to be as professional as possible, and I think this training helps them to think a little more like I do. This year we had the most maintenance we’ve ever had due to all the mud and frozen ground we encountered, and we had the shortest window to do it in. I’m glad all my employees pushed through the winter season, and I’m happy to say we are ready to go when we need to. Now, we just need Mother Nature to cooperate. ■ The author owns Dvorachek Farm and Industry LLC, a custom manure application company in Brillion, Wis.

5/14/20 12:08 PM

FRESH PAINT AGRI-KING RELEASES NEW MANURE TREATMENT Agri-King Inc. has recently introduced Pit-King, its newest product formulated to combat manure solids. Pit-King contains a proprietary blend of enzymes, microorganisms, co-factors, and Agri-King’s patented Bacillus strain. Designed for use in manure pits, lagoons, and slurry stores, Pit-King can be used on dairy, beef, and swine farms. Pit-King’s multi-enzyme blend creates a rapid breakdown of undigested manure solids, while its unique microorganism combination continues manure solid decomposition and also helps reduce compounds like ammonia. Pit-King’s variety of enzymes and microbes also help suppress the formation of manure

foam. This occurs through: • Breaking down undigested fibers in manure, reducing the ability for methaneproducing bacteria to thrive. • Promoting acetate production, which diverts metabolites and nutrients away from methane-producing bacteria. • Producing organic acids, which lower surface tension of manure and reduce methane production. • Producing fiber-digesting enzymes and surfactant compounds, which hydrolyze fibers and disrupt foam formation. Farms also have the opportunity to enroll in the Pit-King Maintenance Subscription Program, where Pit-King canisters will be shipped directly to the farm monthly or quarterly at a discounted price. For more information, visit

KUHN INTRODUCES NEW TILLAGE EQUIPMENT Kuhn North America Inc. introduced the new KUHN Krause Excelerator XT 8010 vertical tillage system. While retaining the current 1 to 5 degree vertical tillage gang angle range, the new Excelerator XT 8010 features an additional XTended range of 6 to 8 degrees. The added capability to increase gang angle will assist the operator in removing shallow rooted weed growth or filling light ruts created from previous harvest traffic or sprayer passes. Individual gang angles adjust using a standard mechanical screw adjustment or

F2 25 Q2 2020 Fresh Paint.indd 2

an optional hydraulic “on-the-go” adjustment feature. The hydraulic option includes an “in-cab” selector that allows the operator to move front and rear gangs simultaneously, retain the same gang angles front to rear, or to adjust the front and rear gangs independently of each other. Additional features include: combination 7-inch front and 8-inch rear blade spacing, a mid-mounted heavy-duty tine section, no-daily grease maintenance bearings, constant-flow hydraulic down-pressure adjustment for wing sections, plus the Star

Wheel treader finishing attachment and 24/7 conditioning reel. The 32-flute, 22-inch, Excalibur VT blades extend blade life and retain a cutting edge as they wear, when operated at 8 degrees or less. Designed to run at 8 to 10 mph field speeds throughout the gang angle range, the new Excelerator XT 8010 provides producers with a “high speed” vertical tillage tool for either fall or spring tillage applications. It is currently available in 30-foot, 34-foot, and 40-foot sizes. For more information, visit May 2020 | Journal of Nutrient Management | 25

5/14/20 12:08 PM

PLACES TO BE Due to the COVID-19 health situation, many meetings and events are being rescheduled or canceled. Please visit the listed websites frequently for updates.

American Dairy Science Association Annual Meeting June 21 to 24, 2020 Virtual Meeting Details: American Society of Animal Science Annual Meeting and Trade Show July 19 to 23, 2020 Virtual Meeting Details: Midwest Poultry Federation Convention
 August 12 and 13, 2020
 Virtual Meeting Details: National Pork Industry Conference August 16 to 19, 2020 Kalahari Resort Wisconsin Dells, Wis.
 Details: U.S. Poultry and Egg Association Environmental Management Seminar September 17 and 18, 2020 Hilton Sandestin Resort Destin, Fla. Details: 
World Beef Expo
 September 25 to 27, 2020 Wisconsin State Fair Park West Allis, Wis. Details: World Dairy Expo September 29 to October 3, 2020 Alliant Energy Center Madison, Wis. Details:

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5/20/20 1:57 PM

THE INNOVATION CENTER FOR U.S. DAIRY is pleased to celebrate the following winners of the 2020 U.S. Dairy Sustainability Awards

Outstanding Dairy Farm Sustainability: Twin Birch Dairy, Skaneateles, NY Rosy-Lane Holsteins, Watertown, WI Threemile Canyon Farms, Boardman, OR

Outstanding Dairy Processing & Manufacturing: Leprino Foods: Greeley, Colorado Processing Plant

Outstanding Supply Chain Collaboration:

Outstanding Community Impact:

Turkey Hill Clean Water Partnership: Turkey Hill Dairy Maryland & Virginia Milk Producers Cooperative The Alliance for the Chesapeake Bay

Sustainable Conservation De Jager Dairy McRee Dairy Netafim Western United Dairies

The U.S. Dairy Sustainability Awards recognize dairy farms, businesses and collaborative partnerships for practices that demonstrate outstanding economic, environmental and social benefits, a longstanding commitment to continuous improvement, and a replicable model to inform and inspire others in advancing dairy sustainability leadership. For more information on the Awards and the 2020 winners visit

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5/11/20 11:00 AM

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