Maximizing Use of Nutrients in Manure


Here’s how to maximize use of nutrients found in manure.

Manure always has been an excellent source of organic and inorganic nutrients. The challenge is knowing how to effectively manage the host of factors that affect the nutrient content of manure.

According to the USDA’s Natural Resource Conservation Service (NRCS) it starts with knowing what nutrients the soil already contains. This can only be determined by using a good home testing kit or sending a sample away to a certified soil testing laboratory. A quality laboratory will be able to assess the present levels of major plant nutrients, micronutrients, soil pH, soil textural analysis, soil organic matter as well as contaminants.

Soil testing prices can vary depending on your state, the lab that is used and the items being tested. The NRCS states that most labs charge from a range of $7-10 for a basic test but the cost increases as more nutrients are analyzed. Soil tests are normally only needed every three to five years but the NRCS recommends yearly testing whenever manure is applied or there is a need for large nutrient or pH changes to the soil.

A recent study conducted by the University of Kentucky found that soil nutrient values will vary seasonally. For this reason, it is necessary to take soil samples at the same time each year. The study determined fall as the optimum time for sampling because this is when soil tends to have an ideal moisture range and nutrient values are at their lowest. Also, if there happens to be a pH problem there is ample time to apply fertilizer or lime to fix it whereas in the spring there is limited time before planting.

Manure matters

Knowing the soil nutrient content is just one half of the equation. The other half is knowing the manure makeup. Manure is made up of organic matter, which improves soil structure, aeration, moisture holding capacity and water infiltration. It also supplies micronutrients such as calcium, magnesium and sulfur, which are beneficial to the soil should a deficiency exist. Both calcium and magnesium also create an added value by producing a liming effect when added to the soil.

Among the many plant nutrients found in manure none are more crucial to farmers then nitrogen, phosphorus and potassium. The over or under application of these nutrients can have adverse effects on crops, which is why proper sampling and analysis is necessary. Nitrogen is the primary building block for plant protoplasm, which is needed for flower differentiation, speedy shoot growth, the health of flower buds and the quality of fruit set. Nitrogen also acts as a catalyst for the other minerals. Phosphorus is needed for energy transfer and storage in plants. It helps plants to mature and promotes root, flower and seed development. Potassium is needed to activate enzymes, form sugars and build up essential oils. It also improves cold weather tolerance. The values of these key nutrients vary based on factors such as animal species, feed, temperature, precipitation, bedding, handling and storage.

According to the Cooperative Extension at Penn State University, for best results, manure should be sampled at the time of application or as close as possible to application because this ensures that samples will be well-mixed and representative of the manure being applied. Manure samples should not be collected directly from the storage facility because of the difficulty in collecting a representative sample.

Iowa State University Extension and Outreach adds that collecting manure samples for nutrient analysis should not be a one-time event. If factors such as feed, management, storage or land application change frequently then samples should be taken on a yearly basis. If there have been no significant changes to these factors for at least three years, then sampling frequency can be reduced. The university extension also points out that much like soils, manure sampling should be taken near the same time every year to account for any seasonal changes.



When choosing manure, determine how much nitrogen is in it. Too much nitrogen can burn plant leaves and roots, whereas too little nitrogen will stunt plant growth. It is helpful to know that most of the nitrogen in manure is in the organic form and must be converted to ammonium or nitrate forms before it can become available to plants. This occurs naturally when microbes in the soil physically break down the organic matter found in manure.

Microbes operate most effectively at temperatures between 70 to 100 degrees Fahrenheit. Microbe activity slows considerably once temperatures fall below 40 degrees Fahrenheit. Soil at 60 to 80 percent water holding capacity provides the most efficient moisture content for microbes. Too much moisture deprives the microbes of the oxygen that they need to survive. A soil pH between 4 and 9 is necessary to support different microbe varieties. There is a sharp drop-off in microbe activity any time the pH goes above or below this range.

Another key point when it comes to nitrogen availability is whether manure is in solid or liquid form. A four-year study done by the University of California found that liquid manure provided almost five times more available nitrogen than solid manure per ton of dry weight. The study also found that 75 percent of the nitrogen in liquid manure was available the first year after application, whereas only 45 percent of the nitrogen from the solid manure was available in the first year. This is good to know because certain crops require more nitrogen than others at certain growing stages.

One way to ensure that plants get the proper amount of nitrogen is by using certain animal manures. Nitrogen content in manures depends in large part on what an animal is fed. Animals that are herbivores like cows, horses and rabbits tend to produce manure that has a low nitrogen content. Manures that are low in nitrogen already have an ideal carbon to nitrogen ratio so they can be tilled directly into the soil without fear of causing plant damage.



Animals that are omnivores like chickens and pigs turn out manure with a higher nitrogen content. A good way to offset the high nitrogen content in manure before applying it to the soil is by composting it with carbon-rich materials like leaves or straw. Decomposition of organic materials is greatly increased when there is a proper balance between carbon and nitrogen materials in manure. Decomposition slows down when carbon is too high and speeds up when nitrogen is too high. Maintaining a carbon/nitrogen ratio of around 30:1 is ideal.

For decomposition also consider that different soil textures play a part in the decomposition rate of manure. Due to less surface area and a lower water holding capacity coarse-textured soils allow for a more rapid rate of manure decomposition. On the other hand, fine textured soils such as clay do not provide adequate space for air to collect, causing less biological activity and a slower breakdown of organic. Also coarse-textured soils have a greater potential to lose nitrate from leaching when compared with fine-textured soils.

Nitrogen can also be lost through a process known as volatilization. It occurs when nitrogen is converted from ammonium to ammonia gas and released to the atmosphere. Volatilization losses increase when manure is located near the soil surface in warm, moist and high pH conditions. Losses from volatilization can be reduced by effectively tilling manure under the soil and applying it in the spring when soil and air temperatures are cool.

Proper application

Once the manure content is determined and the proper application rate is established the next step is deciding when to apply manure to the soil. Jose Hernandez, an Extension educator at the University of Minnesota, said that the timing of manure applications can make a significant difference in nutrient availability to the crop. According to Hernandez, the ideal time to spread manure is in the spring because that is when crop nutrient uptake will be at its peak and losses due to runoff and leaching are reduced.

Fall is another acceptable time for manure application, according to Hernandez, because it allows more time for the organic portions of the manure to break down before the plant needs the nutrients. The only negative to a fall application is that it provides more time for nitrogen leaching to occur. Hernandez said that if fall application is necessary then it should be done later in the season when soil temperatures are below 50 degrees Fahrenheit because low soil temperatures prevent the nitrogen from leaching.

Douglas Beegle, a professor of Agronomy at Penn State University, said all field types can utilize manure as long as nutrient levels aren’t too high to begin with and proper application management practices are taken.

For example, manure that is distributed into pastures without proper management can lead to weed seed problems and parasite eggs. This can be effectively managed by composting manure prior to application. The high temperatures generated in a compost greatly reduce parasite eggs, weed seeds, parasite eggs and other pathogens.

There are other benefits to composting including raising manure pH, reducing odor and reducing bulk, which makes it easier to handle. When composting it is important to note that the longer manure can decompose the lower the nitrogen availability will be.

A study at the University Wisconsin Extension highlighted several types of fields that may be inappropriate for manure application. According to the study manure should not be applied to fields with thin soils over fractured limestone or fractured sandstone bedrock because it can cause significant groundwater problems due to nitrate leaching. Manure should not be applied to fields that have greater than a 12 percent slope because nutrients can be carried off to lakes and streams during thaws or during early spring rains. Manure shouldn’t be added to fields that are within 200 feet of streams, 1,000 feet of lakes or on wet soils and other areas that are periodically flooded unless it is incorporated within three days. Manure application should be avoided on fields with high phosphorus levels.

Photos: Paul Burdziakowski

Manure Application Trends and Considerations


Manure is not only a byproduct for livestock producers, it is also a valuable commodity. As the season begins, producers must keep in mind regulations and application.

Manure is not only a byproduct for livestock producers, it is also a valuable commodity. When manure applications are carefully planned and timed they can take the place of artificial fertilizers. The value of using manure as an organic fertilizer is no secret. Dairy farmers across the country apply manure to their fields in hopes of utilizing the nitrogen (N), phosphorus (P) and potassium (K) from the manure to improve soil health.

“Depending on state regulations, a farm’s soil types and the composition of the manure, farms can sometimes get enough nutrients from a manure application to last through an entire corn crop,” said Justin Wagler of Nutrient Management Partners.

Wagler and his wife, Sarah, operate a custom application business that covers Indiana, Illinois and Ohio. “When manure is used as fertilizer, it is extremely valuable,” he said. “Farms can hire a custom application system and still spend less than if they applied an artificial fertilizer. And they get the organic value of manure.”

State regulations dictate application details, but a well-executed manure management plan allows any farm to obtain the full value that a crop nutrient manure can provide while protecting water, air quality and staff.

“Although manure management on dairy farms is often associated with regulations and permits, it is important for all farms to utilize manure properly since it is a valuable resource of nutrients and proper manure management helps to protect the environment,” said Tamilee Nennich, a dairy nutrition specialist with Farmo Feeds.

Nennich and Wagler share their expertise on the latest trends in manure application, considerations for on-farm practices that may alter the nutrient content of manure and tips for maintaining application records.

Application trends

Gone are the days of simply running a spreader across the fields to dispose of manure. As regulations continue to evolve and an emphasis is placed on environmental impacts, science and sophisticated equipment work in tandem to develop specific application rates that can be adjusted to meet varying needs across a field. In tractor mapping, software plots exactly how much manure was applied to a specific spot in the field.

“We create detailed maps for farmers to retain with their records and so they can submit it to the state along with their other required reports. The maps outline the rate manure was applied at specific locations throughout the field,” Wagler said.

The application rates and subsequently the maps can only be generated based on sample results, both manure and soil.

“It’s important to collect representative manure samples and submit the samples to a certified lab to have them analyzed for major crop nutrients, including nitrogen, phosphorus and potassium,” Nennich said.

Many states only require once-a-year manure sampling, but pulling samples more often can create a more accurate picture of the nutrient content. Some factors impact the availability of nutrients in the manure and ultimately how it is applied in the field. Nennich explained that the nutrition of the animal affects the amount of nutrients in manure, particularly regarding phosphorus.

“When cows are overfed phosphorus, it will be excreted and will need to be managed in the manure through proper applications rates,” Nennich said.

Managing a feeding program to reduce as much over-feeding of nutrients as possible is usually more economical for feeding the cows and it can reduce manure application expenses when manure is properly applied.

Wagler finds that in cattle, dairy and beef, the type of bedding also changes nutrient levels and application rates. “Sawdust and straw have more organic matter to begin with than sand,” he said. “If you have clay fields and use sand bedding, the sand in the manure can be good because it can help the soil come around.”

“Some of the farms pull samples in the spring and the fall so they have closer records,” Wagler said.

The results from soil samples are the other piece of the puzzle. State regulations vary as to how often soil samples must be collected and from how many points within the field. Some producers are sampling more often and are using grid sampling rather than random sampling to have a more accurate representation of the soil types across the entire field. Wagler explained that taking one sample from a 100-acre field may not necessarily tell the whole story whereas grid sampling may show where some parts of the field can take more manure than others.

“It’s important to maximize your manure applications and get the most bang for your buck,” he said. “With grid sampling you may actually be able to apply more total gallons even though some areas within the field receive less than others.”

Wagler noted that one of the newest trends in manure application is the use of drag hoses rather than driving tanks or injectors across a field. Compaction from tank spreaders or injectors can reduce crop yields. “Drag hoses help with compaction issues,” he said.

Application considerations

Application timing is ultimately up to the farmer. However, a spring application may be more beneficial than a fall application.

“I’ve had farmers ask me how much nitrogen they’ll lose over the winter if they apply the manure in the fall,” Wagler said. “I estimate they lose nearly half of the nitrogen compared to spring applications.”

Manure that is applied in early September has a good chance of evaporating into the air, running off and more. If that’s what the farmer chooses, Wagler encourages the use of a cover crop over the top of an application to bind the manure to the soil. “When you have bare dirt, you have more problems with nitrogen and phosphorus leeching out of the soil,” he said.

With new technologies available, manure application rates can be adjusted according to soil type, crop yields and soil fertility. The ability to fine-tune application rates is continually improving as new technologies become more affordable.

Before heading out to spread manure, carefully inspect all manure handling and application equipment to make sure it is working properly. Replace or repair anything that needs to be fixed to prevent leaks and spills.

“Calibrate manure application equipment so that you will know how much manure is applied on the available land,” she said.

Study the field and decide where buffers and sensitive areas are within the field. Consider the location of drainage areas and tile lines. Nennich reminds farmers to take into account specific setbacks that need to be followed in your nutrient management plan.

“Visit with neighbors to inform them of expected upcoming application dates and determine if there are days when manure application might be avoided,” she said.

Watch weather forecasts for wind and rain events that may affect application and avoid making an application immediately prior to predicted rainfall events. Manure that is applied to wet, soggy fields is more likely to runoff or be absorbed by the drainage system rather than infiltrating into the soil.

In the field, additional precautions are needed to ensure that the manure isn’t leeching into drainage outlets or nearby water sources. “Every hour we’re checking in and outbound water ditches and testing for nitrogen to minimize what is leeching into the water,” Wagler said.

Injection applications are one alternative that can help minimize runoff and odor. “Injecting manure or incorporating as soon as possible after application will not only help to conserve the valuable nitrogen in the manure, but it helps to reduce the odor as well,” Nennich said.

Wagler agrees that the new injection equipment used for manure applications creates minimal soil disturbance and puts the manure just under the soil surface. This not only helps with nutrient retention and odor reduction, but also helps reduce erosion and runoff.

Record-keeping essential

Regardless of the size of the farm, maintaining records of all manure application activities is critical. Accurate records are one of the best ways to demonstrate that manure is being handled properly on the farm.

Include the application date, the total acreage the manure has been applied to and the field location. List the amount of manure spread on the fields and the source of the manure. Record the actual nitrogen and phosphorus application rates for each field. If you have access to mapping software, include a map of the manure application in your records as well.

“Manure application periods are very important for livestock producers. Proper management and application of manure is essential to maximize the fertilizer value of the manure, meet regulatory requirements, protect the environment and foster good neighborhood relations,” Nennich said.

Because regulations can vary from one state to the next it’s best to check with your state’s department of agriculture, the local cooperative extension office and or the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS) for specific guidelines.

To learn more about the latest developments in manure management practices, check with your local Extension agent and the entity that oversees your manure management plan on a state level.

Making and Using On-Farm Compost


Making your own compost is one way to keep its cost down, but it still takes time and management to make high-quality compost.

Compost is a valuable soil amendment that has the potential to provide nutrients to crops, improve soil structure, promote microbial activity and suppress plant diseases. However, it is not a cure-all for soil problems, and its use should be part of your overall soil fertility plan to manage nutrients, rotate crops and minimize tillage. Making your own compost is one way to keep its cost down, but it still takes time and management to make high-quality compost.

Opportunities for on-farm composting

Most communities generate significant amounts of waste products that can be composted if collection and transportation issues can be addressed. Some of these materials are relatively easy to compost, such as dairy and horse manures with bedding, while others can be more challenging to compost, such as fish waste or paper mill waste. Yard waste, food processing waste and other off-farm, carbon-based residues may also be available. Most states and some municipalities have regulations that apply to larger-scale compost operations. Before you start composting, find out what state and local rules might affect you.

Clean ingredients

Even if the price is right for a given waste, it has to be suitable for agricultural or horticultural end use. In other words, the raw ingredients used to make compost need to be relatively free of non-compostable materials or toxic contaminants. On-farm wastes like manures are less likely to raise concerns about such contaminants compared to many off-farm wastes, especially when you know the farm or farms that the manure comes from. The use of off-farm wastes can be made less risky through clear communication with the generators of that waste about the standards you require to make high-quality compost.

When accepting a waste stream for on-farm composting, be sure to ask if there is a process in place to remove undesirable materials such as plastic, metal, glass or grass clippings from herbicide-treated lawns. When possible, inspect materials upon delivery before they are added to your compost piles. If contaminants are found, provide samples to the waste supplier as soon as possible and develop a plan for preventing future occurrences.

Composting methods

2 puddles by compost pile

On-farm composting is commonly done in windrows, or long piles that are turned over several times. Piles may be turned by pushing them with bucket loaders, by loading the compost into a manure spreader and reforming the windrow or with a commercial compost turner. If the piles are not turned, they are called static piles. Instead of turning, these may be aerated with perforated pipe and sometimes a blower is used to push air through the pipe.

The composting process

Composers make music, but decomposers make compost. Lucky for us, decomposers are widespread in nature, and compost piles don’t need to be inoculated in order for the raw materials to start decomposing. In fact, a well-made compost pile heats up right away to 130 degrees or more, indicating a rapid rate of decomposition that can continue for several weeks. During this time the pile needs an adequate supply of air and moisture to remain active. Turning can keep the pile aerated while rain or irrigation may be needed if the pile starts to dry out. Eventually, the pile temperature will drop to 100 degrees or so as the compost continues to mature or “cure” into a finished product.

Many microbes do the work

To succeed in making the highest quality compost with the least investment of time and equipment, it’s important to understand the different groups of microbes involved in composting. Obligate aerobes are strict oxygen consumers that die off when oxygen is lacking. Facultative anaerobes can work in both aerobic and anaerobic conditions; in other words they adapt to the oxygen level of their environment. Aero-tolerant anaerobes grow anaerobically in the presence of oxygen; they don’t use it but they can tolerate it. Obligate anaerobes are limited to oxygen-free environments and die off when it is present.

Only the highest quality compost should be used for potting mixes and greenhouse soil amendments. Even if it looks real nice, a laboratory compost test is needed to determine the pH, soluble salts and available nutrient levels.
Only the highest quality compost should be used for potting mixes and greenhouse soil amendments. Even if it looks real nice, a laboratory compost test is needed to determine the pH, soluble salts and available nutrient levels.

Only the highest quality compost should be used for potting mixes and greenhouse soil amendments. Even if it looks real nice, a laboratory compost test is needed to determine the pH, soluble salts and available nutrient levels.

It’s not essential to manage composting as an entirely aerobic process, but it does speed up the compost process and it creates heat, which helps reduce the number of weed seeds and pathogenic organisms. If you have the time and your compost is made from ingredients with relatively low risk of weed seed survival, or food safety risk, such as a plant residues rather than animal manures, then the facultative anaerobes may be an especially important part of your on-farm composting strategy. They function at lower oxygen levels, minimizing the need for (and cost of) manipulating the pile. They’re also responsible for generating some of the disease-suppressing abilities that have been observed with certain composts.

The anaerobic problem

If a compost pile becomes extremely low in oxygen for extended periods of time, the result can be strong odors, a very slow process and the accumulation of phytotoxic (plant damaging) compounds. To avoid this situation without having to turn frequently, compost piles should be built so that they are as self-aerating as possible. This can be accomplished by using materials with sufficient porosity, managing moisture content to avoid soaking and keeping windrows small enough to avoid internal compaction from their own weight. Then, the natural oxygen demand of the compost process will assure a steady low level of oxygen as it diffuses into the windrow to replace the oxygen that is consumed by the microbes.

Time to turn

The porosity of a compost windrow tends to decrease as materials are decomposed, and for a short period of time, when oxygen demand is still high, a windrow may go excessively anaerobic until diffusion of oxygen can catch up. In many cases, the best thing is to leave the windrow alone until it re-equilibrates. But, if the pile is not porous enough, or its core is wet, then turning may be needed to aerate the pile. Keep in mind that aggressive turning further reduces porosity by breaking down the aggregates or small clumps of composting materials, increasing the need for subsequent turning. In other words, the need for frequent turning becomes a self-fulfilling prophecy.

The use of sufficient bulking material and low-impact turning methods (like a bucket loader versus a compost turner) can allow a windrow to remain self-aerating with a minimum of turning. At the outset, raw materials with sufficient porosity must be mixed together to distribute carbon, nitrogen, moisture and oxygen evenly through the windrow. Then, after the initial burst of decomposition and oxygen consumption, a gentle turning can help keep the pile sufficiently aerated. Finally, as the process nears completion, turning helps homogenize the finished compost and mixes in materials on the surface that have not been fully decomposed.

Not too high and not too wet

Windrow height, after settling, should typically be no more than 5 feet unless large amounts of porous materials like straw are being composted, otherwise the core will become compacted. Keeping the windrows small also avoids excess heat conditions, which encourage the loss of moisture. If rains threaten to saturate the windrows, they should be covered. Use either a breathable compost cover, or if using plastic, do not completely cover the sides of the windrows. Leave an uncovered gap along the edge of the ground that will allow air to be more easily drawn into the windrows.

Compost quality

The end use of compost determines how important its quality is. Compost for potting mix must be the very best, while compost for roadside landscaping can usually be of lower quality than that required for food crop production. Typical quality targets for good compost are: a neutral pH, an organic matter content of 40 to 60 percent, a carbon to nitrogen ratio of 10 to 15, low-soluble salts, absence of phytotoxic compounds and weed seeds and good seed germination. You can easily test for some of these attributes yourself by doing a germination test of the compost to see what sprouts when you put a moist sample in a warm location, and by planting a known number of crop seeds in a compost-filled tray and observing germination and growth. Many university and private labs can test other attributes of finished compost.

Spreading the wealth

Compost is often referred to as a soil amendment rather than a fertilizer, but it does contain a significant amount of plant nutrients, even if they are not immediately available. It’s estimated that 10 to 30 percent of the nitrogen available in compost may be released in the year after application. Finished compost typically has an analysis of 1-1-1 (N-P-K). These numbers vary quite a bit depending on what ingredients were used, how they were composted and for how long. If you will use or sell a lot of compost it sure makes sense to have it tested so you or your customers know what they are applying per yard or per ton. (One ton of compost is equal to about 2.5 yards, again, with variation, depending on bulk density and moisture content.)

In general, high rates of compost, perhaps 20 or more tons per acre, can be applied to soils needing structural improvement and additional nutrients, and lower rates, around 5 to 10 tons per acre, can be used on soils with decent, but not great structure and moderate levels of fertility. On soils with very good physical condition and/or excessive levels of nutrients, the use of compost should be minimized, even avoided.

Editor’s note: This article was originally published in the August 2010 issue.

Why We Must Treat Manure as a Highly Valuable Resource

Not testing manure for nutrient content is like buying fertilizer without asking for the analysis.

Manure management is not waste management. We can no longer treat manure as a waste product—it’s a highly valuable resource.

Many farmers still view livestock manure as a waste product that has to be disposed of as efficiently as possible. In this case, “efficiently” means with the least possible investment in time and equipment. In the past, it wasn’t uncommon for farmers to spread an entire winter’s production of dairy manure on the one or two fields closest to the barn, even though those were the same fields receiving the previous winter’s entire manure production. (Hint: When you have to measure application rates in inches of depth rather than tons or gallons per acre, that’s too much manure.)

Fertility on these fields soon reached astronomical levels, “off the chart” on the soil nutrient scale—especially in the case of phosphorus—it can literally take generations to farm excessively high fertility back to normal levels. Ironically, soil fertility would have been even higher had the farmers used good manure management, including incorporation of manure, timing application rates to when the crop needs the nutrients, and avoiding spreading near ditches and streams where runoff could quickly move off-site. I think we’ve come a long way since then, aided by a higher percentage of manure that’s stored (versus daily spread), and by more efficient manure handling equipment, as well as by increased regulations such as CAFO (Concentrated Animal Feeding Operations), and more responsible manure management by farmers and farm employees.

We can no longer treat manure as a waste product—it’s a highly valuable resource. On moderate and large livestock farms, increasing government regulations are dictating when, where and how much manure can be applied to cropland. Also, the non-farming public is increasingly bothered by the smell of manure and by the sight of spilled manure in roadways. Nuisance lawsuits have been on the increase, and farmers have lost their share of them. This will only increase as livestock farming rubs shoulders with non-farm residents. And, small farms aren’t immune to these problems—if dairy manure contaminates a neighbor’s well it doesn’t make any difference if the manure was from a 50-cow farm or a 500-cow one.

Dollars and Sense

Using a recent analysis of the slurry dairy manure at Miner Institute, just the nitrogen, phosphorus and potassium in one, 5,000-gallon spreader load is worth over $100. That doesn’t include the value of the many other nutrients in the manure, plus the soil-building properties of the organic matter. Following are a few ideas to help maximize the value of livestock manure: dollars and sense

The nutrients in manure are highly available to plants. While a portion of the nitrogen in manure is in the fibrous fraction and not available the year of application, the phosphorus and potassium are just about as plant-available as the P and K in commercial fertilizers. And, much of the N that isn’t available the year of application is slowly released over the next couple of years. Therefore, the corn crop in a field that receives manure every year gets a lot of N the year of application, but also a little bit from that applied one and two years ago—just a little bit, but enough to make a difference, especially if manure application rates were high.

Manure is a multivitamin. Micronutrient deficiencies are less likely to occur on fields that receive livestock manure. On average, only about one-third of the nutrients that ruminants consume are used to produce milk and meat; the remaining two-thirds are excreted. These include not only the major nutrients nitrogen, phosphorus and potassium, but a host of other nutrients, many of which we scarcely think about in planning fertilizer programs. Zinc is one of the very few micronutrients commonly deficient in the Northeast, primarily in corn production. We did a comparison of the soil test zinc level in fields at Miner Institute that had been receiving regular applications of manure versus those that hadn’t been manured in recent years. Not surprisingly, manured fields had significantly more plant-available zinc than non-manured fields. Regular manure applications—not every field every year, but every field at least once every few years—will prevent most micronutrient deficiencies because most of the grain we feed our cows was produced in other areas, and with two-thirds of the nutrients passing through the cow into her manure, we’re essentially translocating the minerals in the grain from where they were produced onto our cropland.

Not testing manure for nutrient content is like buying fertilizer without asking for the analysis. If we buy fertilizer we’re sure to know the analysis, but many farmers have never had an analysis on their livestock manure and have no idea of how many pounds of nutrients are in a ton (or 1,000 gallons). Manure nutrient values vary a lot depending on the amount of bedding used, the solids content of the manure, and even the diet fed the herd. (A high-producing dairy herd will usually have manure that’s higher in nutrient content. Therefore, better cows equals better manure.) Since the nutrients in manure are highly available, manure can be used to replace commercial fertilizer, in whole or in part. Farm regulatory officials realize how important it is to know manure nutrient content, which is why CAFOs are required to test every storage or source of manure every year. Therefore, if a CAFO farm has a slurry manure pit and a stack of composted manure, separate analyses are required each year on both pit and stack. All livestock farms should do regular manure testing, not because of government requirements, but to save money on fertilizer. Plus, it’s just the responsible thing to do.

Slurry and liquid manure pits should be tested several times during unloading. If you buy 10 tons of 15-15-15 fertilizer you can be confident that the analysis of the last ton of fertilizer you apply will be almost exactly the same as the first ton. This is not the case with the manure in liquid and slurry pits. Over time there’s separation between the solid and liquid portions of the manure, and the nutrient content of the solid versus liquid fractions are much different. Almost all the phosphorus in manure is in the solids (feces), while almost all the potassium is in the liquid (urine). Agitating a large manure pit seems to stir it up quite a bit as the top crust gets broken up, but as soon as agitation is done some resettling and separation occurs. The result is that as the manure is pumped out, even if periodic re-agitation is done, the analysis of the first third of the manure removed will be a lot different than the last third.

We found this happening as we unloaded the slurry manure pit at Miner Institute. The first third of the manure we spread was very low in solids and since the phosphorus is in the solids and the potassium in the liquids, it had a wide ratio of K to P. But, as we pumped the pit down, the solids content increased and the ratio of K to P narrowed considerably. The last third of the slurry had by far the most phosphorus and the narrowest ratio of K to P. Pennsylvania State University sells a manure sampling kit containing multiple sample bottles and recommends sequential testing of slurry pits at least once. That recommendation was made before the price of fertilizer increased by multiples; with current fertilizer prices I’d recommend sequential sampling—three samples should be enough—every year because differences in precipitation and rations can combine to change nutrient content.

We used to say that one of the drawbacks in fertilizing with manure was that we couldn’t change the nutrient content as we can with commercial fertilizer. Well, we still can’t change the nutrient content, but we can use these significant and predictable differences in K to P ratio in deciding what fields to manure first and which to manure last. Fields testing high in soil test P (usually those close to the barn) get the first manure out of the pit since each tanker load contains a lot less P in relationship to K. Fields testing low in P get the last manure out of the pit, which is higher in solids content, and each tanker load contains a lot more P. This should be an easy sell to farmers: if a farmer had one load of manure that was only 2 percent solids and another load that was 6 percent solids, which do you think would be more economical to haul a few miles from the home farm to apply on what is often the lowest fertility fields? Nobody likes to haul manure that’s only 2 percent solids, but since it has to be hauled, close is better than far.

In Summary

Even moderate-sized livestock farms have many thousands of dollars of highly plant-available manure nutrients. A small investment in time, manure analysis and planning manure application schedules (rather than taking the simplest route) can go a long way towards reducing commercial fertilizer needs.

Editor’s note: This article was originally published in the March 2009 issue and has been updated for accuracy.

Executing the Perfect Manure Management Plan


Establishing a management plan minimizes hazards while enhancing crop value.

A livestock farm of any size must consider how to handle the manure produced by the animals raised on the property. By default, smaller farms will have less volume than large operations, but both should be equally committed to creating and following a manure management plan. A well-executed manure management plan allows any farm to obtain the full value that a crop nutrient such as manure can provide while protecting water, air quality and staff.

“Manure gives off nutrient emissions like nitrogen, phosphorus and greenhouse gases, which are a nuisance to the environment,” said Victor Cabrera, Associate Professor and Extension Specialist in Dairy Farm Management, University of Wisconsin-Madison.

With increasing concerns for environmental conservation, manure management plans for livestock farms of all sizes are critical. Several types of manure management strategies often depend on the size of the farm, type of livestock and state regulations.

Composting is one manure management practice growing in popularity. While composting offers many benefits, including destroying weeds and pathogens and stabilizing nutrients as organic compounds, if not handled properly, it can create runoff that can affect ground water.

Large farms with herds producing significant volumes of manure dictate the need for a manure storage system such as a lagoon, pond or pit. Designed to hold manure until it can be spread on fields, the deep holding areas can pose several hazards to humans and livestock.

Pit or covered storage systems can create a buildup of toxic gases including hydrogen sulfide, ammonia, carbon dioxide and methane. The most deadly gas, hydrogen sulfide, smells like rotten eggs and is heavier than air. In high concentrations it is fatal to humans and animals in a few seconds. Stored manure also emits ammonia gas, which smells like bleach. The alkaline gas can cause burns in the eyes, throat and lungs.

Manure also gives off carbon dioxide and methane gas; both are odorless and require detection or monitoring equipment to detect the gas levels present. Though neither gas is as toxic as hydrogen sulfide or ammonia; both gases pose risks. Carbon dioxide replaces oxygen in the air and it can suffocate people and animals. Methane is flammable and explosive in confined areas and since it is lighter than air, it rises and collects along roof lines. Manure management plans that include powerful ventilation systems can mitigate many potential hazards.

In addition to dangerous gases, manure gives off debris. “Another hazard is caused by particulate dust and others that are carried in the air,” he added. The particulate dust can include airborne organic particles including bacteria, fungal spores and endotoxins.

Minimizing manure hazards

When raising livestock it’s impossible to eliminate manure. However, with sound management practices it is possible to lessen the opportunity for hazards to occur.

“Implement lagoons/ponds to deposit manure and prevent it from going downwards,” Cabrera said. A storage pit prevents manure from leeching. Because lagoons or ponds are deep they can pose drowning hazards. Install a fence around the perimeter or cover the pit to lessen the chance of drowning.

“It’s better if these facilities are covered,” he said. A covered facility lessens the chances dust and particles are released into the air. If a lagoon is covered, it must be well-ventilated, especially during agitation and pumping to avoid exposing people or animals to toxic gases. When the manure is agitated or pumped neither humans nor animals should not be in any adjacent buildings close enough to be affected.

In addition to safe handling techniques, livestock management practices can also contribute to minimizing manure hazards. “Clean up housing facilities and milking parlor frequently and move manure to the storage facility,” he said. Maintaining clean quarters limits the amount of dust, pathogens and odors that are naturally present in manure.

A focus on efficiency can also mitigate manure hazards. Implement processes that can improve productivity and production. “Any management that increases the production reduces the amount of manure being produced per unit of milk produced and therefore is more environmentally friendly,” he said.

“Composting or bio-digesting the manure together with other organic materials is an option,” he said. “Bio-digesting has the additional advantage to produce energy, which could valuable.” Treating manure, either in a digester or by composting, removes the microorganisms that are potentially harmful to humans. “If you prefer to use the manure in a bio digester or to produce compost or humus, all or most of the microorganisms that could be harmful to people and animals disappear after these processes,” he noted.

At a minimum, placement and proper management of composting piles is important for limiting the potential for runoff. Compost piles should be placed away from surface or groundwater sources to limit contamination of water sources. Individual states may have specific composting guidelines in place.

Best of all, after biodigestion or composting, nitrogen and phosphorus are still present making the “treated” manure a nutrient-full option for fertilizer on crops. Manure nutrients help build and maintain soil fertility. Manure can also increase the soil’s water-holding capacity, lessen wind and water erosion, improve aeration and promote beneficial organisms.

Read more: Manure Management: From Compost to Energy

Following regulations

With an increasing focus on environmental conservation, manure handling practices are often required to follow specific regulations. “CAFOs, operations that have more than 700 livestock units (about 700 cows) are required to keep and provide a nutrient balance of the farm,” Cabrera said. A nutrient balance is a record of how much nutrient comes in and how much leaves and therefore how much potential remains or is lost on a farm.

“Organic operations that are certified are also required to keep a nutrient balance record sheet and all documentation needed,” he added. “Dairy farmers are in general committed to environmental stewardship and many of them will do best management practices to reduce or improve environmental impacts voluntarily.”

Because regulations can vary, check with your state’s department of agriculture, the local cooperative extension office and or the United States Department of Agriculture’s Natural Resources Conservation Service (NRCS) for specific guidelines.

Read more: Manure Application Regulations Cumbersome

Handling Manure in the Summer

manure handling

As dairy farms have increased in size, a higher proportion of livestock manure is stored in pits or lagoons. This has the advantage of allowing the farmer to spread manure when he wants to (subject to winter application restrictions that differ by state) rather than when he has to, as in the case of daily spreading.

Another change with increased herd size is a move from stanchions and tie stall barns to free stall barns. This has resulted in a significant reduction in the amount of used bedding – straw, sawdust, etc. – in the manure. Less fibrous material in the manure (particularly straw) makes it easier to apply to alfalfa and grass fields instead of most or all being applied to annual crops such as corn. This is convenient for farmers but presents potential problems, including the offensive odors in liquid manure.

Following are some ideas to consider as you head for the fields this summer, manure spreader or tanker in tow.

Where should I spread?

One of the best places for summer manure applications is grassland. With judicious use of summer manure applications, farmers can supply the necessary nitrogen for second and subsequent harvests of grass as well as most and perhaps all the phosphorus, potassium and other nutrients needed by the crop.

Manure also can also be used for first-cut grass, but often these fields are still too soft when it’s time to apply nitrogen – which should be at first green-up. Plus, there’s already plenty of other fieldwork to do at that time of year.

Depending on the nutrient analysis of dairy manure and forages, you also may need to apply sulfur, which is an essential nutrient. Because of greatly reduced industrial air pollution in the past generation, the amount of sulfur we get from rain and snow is a fraction of what it once was. (Is it too clever to state that sulfur depositions have declined precipitously?) If you need sulfur, a good way to apply it is as an early-spring topdress of ammonium sulfate on grass or mostly grass hay fields, either applied straight or as a 50-50 blend with urea, which, for cost reasons, is my preference.

We need to lose the idea that manure (or nitrogen, for that matter) is harmful to alfalfa. It’s not; in fact, one of the main reasons we don’t recommend fertilizing alfalfa with nitrogen fertilizer is because it’s not economical – the small yield increase wouldn’t be enough to pay for the fertilizer. (Many years ago when I was doing some farm consulting in Hungary, their fertilizer prices were so low that their agronomists were recommending the application of urea to straight alfalfa.)

When applying manure we’re operating under a different set of economic and practical guidelines because one way or another we’ve already paid for the nutrients in the manure. The nitrogen in manure won’t hurt the alfalfa while the potassium and other nutrients should increase yields where soil fertility levels are inadequate. Alfalfa-grass fields, especially those that have been established for two years or more, are excellent candidates for summer manure applications. The damage we do to alfalfa during manure application isn’t from the nutrients in the manure but from wheel traffic (more on this in the next section). That’s why you might want to avoid topdressing manure on first-, and perhaps second-year stands.

Read more: Use caution when topdressing manure

Timing may not be everything, but it’s up there

One of the challenges of topdressing manure on hay land, especially alfalfa, is the need to get the job done as soon as possible after the crop is harvested. Modern manure spreaders have wide tires and the weight of a loaded spreader can damage the crown buds and new shoots of alfalfa.

The longer you wait, the more the damage. There’s been plenty of research on this topic, including at least two trials at Miner Institute in Chazy, New York. It’s estimated that the yield of the alfalfa plants run over by a manure spreader wheel decreases by 5 percent for every day of delay between harvest and manure application. So, if you wait a week after harvest before manure application you’ve lost over a third of the yield of those squashed plants.

Application timing isn’t quite as important with grass because there aren’t any crowns to crack or buds to damage, but consider this: While alfalfa grows from crown buds, grass regrows from the cut stems. So “painting” several inches of regrowth with a coat of liquid or slurry manure could result in some of these manure solids remaining stuck to the plant until it’s harvested. Fortunately, most manure pathogens are killed by the ensiling process – more by the high acidity than the temperatures of fermentation – but some pathogens may survive.

Research at Miner Institute found that topdressing manure three and seven days after first-cut alfalfa-grass harvest resulted in significantly higher ash concentrations, with the highest ash level found after the seven-day delay. And the damage to the alfalfa with a seven-day delay was severe enough that we could still see the wheel tracks several weeks after application. Opinions differ on how much damage wheel traffic does to alfalfa crowns, but I’ve dug up enough plants with crowns split down the middle, resulting in the development of tap root diseases, that I’m a believer. Some crown and shoot damage is likely even if manure is applied the same day the crop is harvested, which is why I don’t recommend manure application on newer stands.

Be a considerate neighbor

You may think that manure is the sweet smell of success, but that doesn’t mean that your non-farming neighbors do! You have to apply livestock manure, but perhaps not on the field next to your neighbor’s house on a Friday afternoon or on a summer weekend. In fact, you might make a good impression by asking in advance if there are a few days (graduations, weddings, family reunions, etc.) when your neighbor(s) would most appreciate your spreading somewhere else.

This is from a fellow who lived next door to a dairy farm for many years. Most farmers have enough options as to when and where to spread that they can still get the job done while being a good neighbor. Even when spreading on weekdays, try to apply manure near residential areas in the morning. Morning applications will have the chance to dry (with the resulting decrease in odors) by the time the nine-to-five set gets home from work. Spreading in the morning is also good because early in the day the air is rising, taking manure odors with it, while late in the day the air is settling. Being a good neighbor also applies to any manure spills. The best idea is to prevent them, but accidents happen. If they do, clean them up as soon as possible. Coating a muffler or catalytic converter with manure and then parking the car in the garage equals no joy!

Read more: Manure management: from compost to energy

Manure Management: From Compost to Energy

Anaerobic digesters

Anaerobic digesters are an important part of manure management.

Anaerobic manure digesters, also known as methane digesters, collect manure and convert the energy stored in its organic matter into biogas. This gas consists primarily of methane, carbon dioxide and other trace gases. Anaerobic digestion is a biochemical degradation process in which organic matter is decomposed by bacteria in the absence of oxygen. The digester must be airtight for anaerobic digestion to occur.

The methane is used to produce gas or electric energy for on- or off-farm use. In general, manure for digesters should have a solids concentration of about 14 percent or less. Also, the manure should not contain soil, sand, stones or fibrous bedding materials, although it can be processed to remove those materials.

Read more: Can you harvest waste?

Animal wastes, dairy manure in particular, can be ideal feedstocks for anaerobic digesters. Food processing wastes and wastewater often can be excellent feedstocks to add to the manure, but the digester must be designed or adjusted for it. Food wastes typically have high energy content because of their high ratios of volatile to total solids. Cornell University research found that cheese whey, for example, with its high percentage of organic matter, is more purified than animal manure. The methane potential varies, but the methane content of biogas with food waste is typically higher.

Anaerobic digesters yield numerous environmental benefits. Odors are vastly reduced. Flies are diminished. Greenhouse gas emissions are limited. Due to heat, the potential for pathogens to enter the surface or groundwater when spread on crops is considerably reduced, thereby improving water quality. Manure management is easier. Also, the effluent from the digester for crop use is richer in nutrients and has fewer weed seeds. Animal bedding can be reused. The heat and/or electricity generated saves money for the farm. Plus, the excess energy can be sold, producing income for the farm. Handling wastes from other entities, such as other farms and food processors, also can be an income source.

Cost is the biggest disadvantage. Anaerobic digesters are so expensive that feasibility studies are typically recommended prior to any serious consideration. In addition, the design must be suitable for the farm’s particular operation and activities, management skills, future plans, geographic location, availability of funding and other factors. Government, private and university sources urge technical research before undertaking an anaerobic digester project.

Read more: Handling manure: cold weather implications

Experts advise talking with owners and operators who have tried or currently use a digester. Patrick Topper, who manages the poultry manure gasification plant at Gettysburg Energy & Recovery Facility in York Springs, Pennsylvania, said to view a digester as manure management. Odor reduction is a primary reason for digesting manure. Keep in mind that digesters do not make manure disappear – the same nutrients are retained. Topper advises farmers contemplating a manure digester to not think of the digester as a power plant. “You’re not going to make much electric energy,” he said. Topper strongly urges a power purchase agreement with the power company. Hiring knowledgeable people is critical, he added, noting that early failures of the digesters in the ’70s and ’80s were caused by people dabbling in technology without expertise.

The first digester for a swine operation nationally was started at Rocky Knoll Farms in Lancaster, Pennsylvania, by Harlan Keener, now deceased. His widow, Shirley, recalls that he was very much involved in researching the technology with extensive travel overseas, including China. She reports that their farm was very satisfied with the digester. “It kept down odors,” she said. Rocky Knoll also added waste milk products from several dairy processing plants to the digester. They sold their excess energy to the grid.

Mike Brendle had 80,000 laying hens when he operated Brendle’s Egg Farm near Somerset, Pennsylvania. He advocates getting help from experienced people and recommends a digester if handling the liquid effluent is feasible. The limestone in feed created sediment, which demanded maintenance. But odor and flies were decimated, and he saved $2,000 per month on electricity costs.

Read more: The effort of waste

The digester at Oregon Dairy Farms in Lititz, Pennsylvania, owned by George Hurst since 1985, was expanded in 2010. “It works well for us,” he said. It produces energy for the farm’s 435 milking Holsteins operation, their full-line grocery store, restaurant, gift shop and farm buildings. They added another tank and a larger engine in 2010. His partner-son monitors the computerized controls and changes oil every couple of weeks. Grit from the cows’ hooves has required maintenance to drain every two years. Food waste from a beef processing plant nearby is added to the digester. A big advantage is significantly less odor in the lagoons.

The generator at Penn England Farm, Williamsburg, Pennsylvania.
The generator at Penn England Farm, Williamsburg, Pennsylvania, has produced electricity and heat for the dairy operation since 2006. Members of the England Farm family researched and visited digester systems in California, New York and Wisconsin as well as Pennsylvania for several years prior to initiating their manure digester project.

Environmental benefits

The Environmental Protection Agency (EPA) estimates the benefits from digesters of avoiding greenhouse emissions in 2014 to be 3 million metric tons of carbon dioxide equivalent. Plus, the EPA’s estimate of energy generated during 2014 was 948 million kilowatt hours equivalent.

Of the 247 anaerobic digesters operating on livestock farms, 202 accept dairy manure, 39 hog manure, eight beef manure, seven poultry manure and eight mixed. (Some of the 247 accept more than one animal type.)

However, the EPA’s AgSTAR program estimates that biogas recovery systems are technically feasible at over 8,000 large dairy and hog operations. Potentially, those farms could generate more than 13 million megawatt-hours of energy annually and displace about 1,670 megawatts of fossil fuel-fired generation.

New technologies have spurred growth. But, although technically feasible, economic feasibility varies. In the EPA’s assessment of the market potential for biogas energy projects at dairy and hog farms, the agency estimates twice as many swine operations as feasible candidates than dairy farms. Of the top 10 states for electricity generating potential from manure biogas recovery systems in dairy farms, the EPA includes over 100 dairy operations in New York state.

Read more: Poultry bedding options

Of the different technologies used in 2015, 42 percent used a plug flow design system, 38 percent used a complete mix and 15 percent used a covered lagoon. The AgStar Anaerobic Digester Database on the website,, identifies the design features of U.S. livestock farms, and importantly, features stories from the farms that highlight operator experiences. This data can help a prospective farmer evaluate different design systems for his own operation.

While recovered biogas can generate electricity to fuel boilers, and create pipeline quality gas or compressed natural gas that can be used as fuel, the most frequent usage is electricity generation or combined heat and power.

Information sources

As noted, anaerobic digesters are costly. Recognizing the numerous benefits to the environment, both federal and state programs assist with information and financial incentives. The EPA’s AgSTAR site has links to a wealth of data. The Natural Resources Conservation Service (NRCS) national website,, has links to financial assistance and technical assistance.

The AgSTAR site includes highly descriptive case studies. Many were prepared by Topper.

The Database of State Incentives for Renewable Energy (DSIRE), searchable by ZIP code at, presents state, local, utility and selected federal incentives for renewable energy. The list specifies when it was last updated, which can be valuable, for example, noting that the Commonwealth of Pennsylvania has been changing its net metering regulation.

The National Conference of State Legislatures database on renewable portfolio standards (RPS),, reports the requirements for utilities. New York, New England and Pennsylvania have created RPS to stimulate market demand.

Feed-in tariffs encourage renewable electricity by mandating a set price for providing energy to the grid. Maine, Rhode Island and Vermont have this measure.

Washington State University has scheduled a webinar series on anaerobic digestion from February through April. The topics include dairy nutrient recovery technologies, biochar production potential, agronomic evaluation of recovered fertilizers, enterprise budget calculator and a decision support tool for gaseous emissions and nutrient management. To register, visit

Read more: Adding liquidity

Photos: Bob Ferguson

Manure Application Regulations Cumbersome


The regulation of manure application in the Northeast is highly variable. In Vermont, producers are prohibited from field application during the winter months, setbacks are mandated, and the Vermont Agency of Agriculture, Food and Markets (VAAFM) is currently reviewing rules that could potentially restrict application even further.

Ryan Patch, VAAFM senior agriculture development coordinator, said the agency has a number of rules on the books for managing storage and application of manure on the landscape. The first, the winter spreading ban, “prohibits the application of manure on farm fields from Dec. 15 to April 1,” Patch said. “There are exemptions for emergency situations, such as a failure of a manure pit.” The rules were codified in 1995 by the Legislature as Accepted Agricultural Practices (AAPs). Under a new law signed by the governor last June (Act 64), lawmakers have renamed them Required Agricultural Practices (RAPs), and have directed VAAFM to rewrite them “to reflect some additional requirements to meet new performance measures as it relates to water quality in farming,” he said.

Under the draft rules, all storage facilities built or changed since 2006 have to meet USDA Natural Resource Conservation Service (NRCS) standards. Field stacking of manure would be banned in areas subject to flooding and would be subject to a 200-foot setback from surface waters and water supplies meant for human consumption and 100 feet from ditches and other conveyances to surface waters. The AAPs, in contrast, only required a 25-foot setback and a vegetative buffer for medium and large farms.

In addition to the winter application ban, the draft would restrict manure applications in other ways. Applications would be prohibited on fields of 10 percent slope unless there are permanent vegetative buffers protecting surface water; they would also be prohibited on fields high in phosphorus, water saturated, or frozen or ice covered. Producers would have to keep application records.

The RAPs have to be finalized by July 1. Patch said there are many winter manure storage strategies that are still an option under the draft RAPs, such as stacking at appropriate locations or maintaining a storage facility like an earthen ground structure. “We have a lot of flexibility for farms to meet these standards,” he said. “We recognize that a 400-cow dairy and a 20-cow dairy have different needs in managing their herd.”

There are fewer 20-cow dairies in Vermont than there were before the 1995 rules took effect. But there are fewer dairies of other sizes, too. Between the 1992 and 2012 Censuses of Agriculture, the number of dairy herds in Vermont slipped from 3,185 to 1,075. The 66 percent decline is steeper than the national dairy farm reduction of 59 percent in that time. In 1992, over 53 percent of Vermont’s herds had 50 cows or fewer; that’s down to 41 percent in the 2012 Census.

“I think it’s important to know that there certainly have been changes in farm size and farm structure,” Patch said. “As farms expand or new farms start, there have been new standards put in place with regards to how structures are constructed, so certain structures when they were installed in the ’80s may have met standards then, but some of them have reached the end of their operational lifetime and need to be upgraded or expanded in size.”

But some of the draft proposals have Darlene Reynolds worried. Reynolds, who with her husband, Newton, milks around 650 cows in the town of Alburgh, is chair of the Farmers Watershed Alliance (FWA). Founded in 2006, the alliance is a voluntary board that helps farmers address water quality issues. Reynolds said FWA has been working with them on nutrient management plans and figuring out which critical areas on their farms require special protection, like cover crops or permanent vegetation.

Farmers are also finding innovative ways to use the excess on the farm. Some are double-cropping, increasing crop production and nutrient uptake. Others are building more storage.

Tensions surrounding issues

“It has been a little bit of tension between farmers and the Department of Ag, especially for the small producers,” Reynolds said. “We’ve found many different issues that have happened; some of them, farmers didn’t even understand that they were issues…They’ve gone from not really doing a whole lot of looking around to, in our area, doing surveys.”

This past year, FWA has also tried to influence VAAFM’s proposed regulations under Act 64. Reynolds said the 10 percent slope proposal is “a pretty tall order because we live in a mountain state, and that actually is going to take a lot of land out of production.”

Can they write the rules to both clean up the water and let farmers operate normally? “That’s a tough question. I’m hoping that farmers and the agencies helping to regulate us can work together. Am I worried? Yes, because you have to still farm; you still have to make a living at it, and it still has to be sustainable. I do worry a lot that the rules might make the economics almost impossible to continue farming.” The Reynolds are planning a new manure pit next spring; it will help them get into compliance with the requirements but will cost a lot of money, although they’ll get some help from state and federal programs.

She said, “I’ve sat in a room with scientists, people that are studying our lakes for years, and asked if we literally put a wall around the lake and never allowed any phosphorus to enter it, how long would it take to clean the lake? The answer that I got in that room was between 100 to 125 years…We understand that we all do our part to keep phosphorus off the land, but when you’re told that at the same time the public has a perception of you, it’s tough.”

Looser rules in the Keystone State

In Pennsylvania, the regulatory pressure isn’t nearly as stringent. “I think everybody’s kind of on the same page,” said Dr. Douglas Beegle, professor of agronomy at Penn State University. “I think the regulators, at least at the state and local level, have been fairly reasonable; they’ve made an effort here to keep it as local as we can. For example, our plans are reviewed at the local, county level; they’re not sent to Harrisburg or Washington.”

Every farmer in Pennsylvania that uses manure has to have a manure management plan that lays out what crops they grow and what the acceptable application rates, timing and methods are. Most farmers can write their own plans and for them the regulatory body is the local soil conservation district (SCD), which does not approve the plan but can conduct spot checks.

The plans for farms with high animal density – more than two Animal Equivalent Units (1 AEU=1,000 pounds live weight) per acre – have to be written by a certified planner. These are three-year plans that are reviewed and approved by the local SCD board. About ten percent to 15 percent of Pennsylvania farms fall under this category. The law was changed in recent years, and if manure is being exported, the plan has to indicate what the recipient is going to do with it. “In our original regulations, all a farmer basically had to say was, ‘I’m exporting my manure to Farmer X,’” Beegle said.

He said Pennsylvania, along with all other Northeastern states, adheres to a phosphorus index; it evaluates the potential for phosphorus loss and can restrict manure applications. The main criterion for the manure management plans, though, is nitrogen; applications are tied to how much N the planned crops need.

Beegle said the market varies for excess manure, and working against it is the tendency of large swine and poultry integrators to concentrate all of their contract growers in one area. “You have a lot of these farms with excess all in the same area, so that creates a problem for what you can do with your excess manure,” he said. “And we’ve had people get pretty innovative in this; there are at least two manure auctions that occur, where large poultry producers actually hold an auction, and farmers and brokers bid on their manure.” Manure brokers in Pennsylvania have to be certified.

Farmers are also finding innovative ways to use excess on the farm. Some are double-cropping, increasing crop production and nutrient uptake. Others are building more storage. “If they have year-round storage, or six months or three months, that’s all part of the overall planning process,” Beegle noted. “It’s a very comprehensive plan in that regard; it’s not just how much you can spread on this acre.”

Penn State, other universities, and USDA’s Agricultural Research Service have also been looking at practices like low-disturbance manure injection. Beegle said as farmers have moved away from tillage, more manure has stayed on the surface where it can volatilize or run off. Low-disturbance injection is more expensive and makes application slower, but several commercial manure haulers have bought the technology and offer it to their customers.

The researchers have also embraced the use of cover crops, which Beegle said may help resolve some of the Environmental Protection Agency’s concerns about Pennsylvania still allowing year-round applications. “We have a lot of small dairies in particular that can’t store their manure for a whole year,” he said. “One of the things we really stress is having cover crops, so if we’re spreading manure in the fall or even winter, we’re not spreading on bare ground. The cover crop can help reduce runoff in the winter, and a live crop, when it warms up, will be growing and take up nutrients.” All farms are required to have cover crops or residue if they apply in the late fall and winter. There are also setbacks and other limitations on when, where and how much manure can be spread in the winter.

The requirement that each farm have a manure management plan goes back to the early ’70s, but “really, until recently, it’s rarely been enforced,” Beegle said. That has changed with pressure from the federal EPA to meet the goals of the Total Maximum Daily Load requirements for Pennsylvania and other states in the Chesapeake Bay Watershed. He said, “EPA wants some kind of documentation that farmers really do have (manure management plans); it’s not enough to say the law requires it. We’ve been doing a lot of education; we’re just trying to help farmers develop these plans, get into compliance.”

New York’s approach

New York also allows year-round manure applications. A 2011 proposal by NRCS to prohibit winter applications was rejected. It was opposed by New York Farm Bureau, whose deputy director-public policy Kelly Young said, “We still oppose a calendar ban on manure spreading, but our policy acknowledges that there are certain times in the winter and other times during the year when it’s not appropriate to spread, and all of our farmers aim to become more and more sophisticated on when are good and appropriate times to spread.”

The New York Department of Environmental Conservation (NYDEC) has just issued revised requirements for Concentrated Animal Feeding Operations, which are federally regulated and need National Pollution Discharge Elimination permits. As in most states, New York runs the program on behalf of the federal EPA. Young said the NYDEC is not proposing a winter spreading ban, nor is Cornell University, which “has guidelines for spreading in adverse conditions when things could be riskier…We’re supportive of that; we want these decisions to be science-based. Just because the calendar says it’s winter doesn’t mean that it’s a bad time to spread. If the ground can absorb those nutrients and we can avoid runoff, then it doesn’t entirely make sense to prevent that from happening.”

Young said nonpermitted applicators already face constraints. “It’s always illegal to pollute the waters of the state, so you always have to protect from doing that,” she said. Farm Bureau recommends dairy operators join the New York State Department of Agriculture and Markets’ “Agricultural Environmental Management” program, which she said “helps work farmers through the thought process of making sure they’re considering all the aspects on their farm, and making sure they are taking care of their animals and taking care of their land in a way that is the most beneficial to the environment.”

Can You Harvest Waste?

Cover Photo: Twelve-inch lateral pipes every 2 feet on-center are installed to capture the heat from composting material.

Composting for fun and profit.

Cover Photo:  Twelve-inch lateral pipes every 2 feet on-center are installed to capture the heat from composting material.

It is no secret that farmers have mastered the ability to harvest a crop. Many farmers are discovering that they are also able to harvest energy from their natural surroundings: the wind and sun and the waste on their farms to generate power, cut operation costs and, in some cases, identify new sources of income.

Medium and large-scale livestock farms are finding ways to implement renewable energy alternatives for financial and environmental reasons.

“Ninety-eight percent of all modern agriculture relies on natural gas, petroleum and fossil fuel byproducts,” said Josh Nelson, director and partner of AgriLab Technologies. “It is projected and anticipated that fossil fuel costs will double in the next two to four years.”

Composting organic material and converting it into useable energy is one way farms can reduce their dependence on fossil fuels. All farms generate organic waste that can be composted. For livestock farms, that organic material comes in the form of manure. Composting is either an aerobic or anaerobic process; both of which have the potential to generate energy. Anaerobic composting is based on fermentation and occurs when little to no oxygen is present. Anaerobic Digestion Systems (ADS) are being installed on farms to capture methane, a natural byproduct of the anaerobic composting process. Nelson cautions that ADS systems can be costly to install and can be dangerous because methane is explosive and odorless, making a leak hard to identify.

The middle of the barn where all of the heat from the composting material is collected and converted into usable energy.
The middle of the barn where all of the heat from the composting material is collected and converted into usable energy.

Conversely, aerobic composting requires oxygen to decompose. Rather than producing a gas, aerobic composting produces heat, which can be captured and reused as a source of energy. Traditionally, aerobic composting is set up in a chamber or an outdoor windrow and requires continuous flipping and turning to provide enough oxygen. Nelson has developed a system that will allow aerobic composting inside a dedicated facility.

“We know that we can generate 1,000 BTUs per ton of material being composted per hour from properly managed composting material,” Nelson explained. Depending on the size of the farm, enough energy can be produced to power the entire operation with excess that can be sold back to the public power grid.

Seven years ago, New York farmer Sean Quinn began composting all of the bedding used on his 2,000 heifer replacement farm. His deep-rooted passion for conservation led him to research ways to reduce waste even further on his farm. Through his research, Quinn met Nelson and committed to installing a Passive Aerated Windrow System (PAWS) on his farm.

The technology used on Quinn’s farm is simple. First, he built a 55-by-130-foot barn and divided it in half. Two cement walls were poured to create separate production areas, allowing for expansion as the volume of composting increases. Twelve-inch diameter PVC pipe and fittings were laid every 2 feet on center to direct the heat from the compost into a manifold system where the heat will be captured and used to generate hot water and electricity for the farm. Ideally, the final composted material will be clean enough to be reused as bedding for the older heifers on the farm.

6-inch piece of drainage pipe at the isobar array, the fundamental component of the thermal heat recovery system.
Looking into the 36-inch piece of drainage pipe at the isobar array, the fundamental component of the thermal heat recovery system.

A 36-inch piece of ADS pipe is the foundation of the entire process. Inside 10 stainless steel ISO #10 pipes fill the chamber. This isobar array assembly is sealed and charged with a refrigerant fluid designed to capture and transfer the heat. During the process, the isobar will also create condensation. “Because the system is a sealed environment, theoretically the water from the condensation should be pure enough for drinking water for the calves,” Quinn explained. The water will undergo testing before being used, but in Quinn’s quest for zero waste on the farm, his goal is to use the water for the herd.

Though the pipes are exposed during construction, everything will be insulated before being used to avoid heat loss. “The key thing is to conserve energy and not to use any fossil fuel,” Quinn emphasized. Each of the PVC ball valves that will control each zone within the barn will be manually operated. “I will be in and out of the barn all day, it’ll be easy to monitor each zone and turn the valves on or off as necessary,” he added. Using the same materials as those used with outdoor woodstoves, it is possible to transport the heat generated up to 500 feet with minimal loss for easy use on the farm, Nelson noted.

Even though the project took five years from the time it began until its completion in the fall of 2010, Quinn is eager to benefit from the exceptionally high return on investment. The thermal heat system will generate more hot water and heat than the farm can actually consume. “We expect to save $220,000 annually on energy costs. If a second phase of the project can be implemented, then electricity can also be produced, and then the savings will double. More testing will be necessary to determine the feasibility of the second phase,” he said.

close-up view of lateral pipes
A close-up view of lateral pipes used to transmit the heat captured by composting material.

A thermal heat recovery system is not only for large-scale livestock facilities. Farms with as few as 25 to 30 head of cattle have the ability to produce enough compostable material to benefit from a thermal heat recovery system. “Enough manure is generated on a dairy of this size to heat all of the buildings on the farm,” Nelson noted. Despite an initial investment ranging from $37,000 to $100,000, depending upon the size of the system, Nelson urges farms to consider a thermal heat recovery system because the benefits will outweigh the investment.

Not only will a thermal heat recov-ery system reduce utility expenses, it also provides additional benefits that lead to reduced expenses. “Composting shrinks the volume of material you have to haul away by 35 to 45 percent,” Nelson explained. That equates to fewer trips, less fuel and decreased labor associated with moving the material.

“A lot of people don’t realize that the planet loses 1 percent of our topsoil annually,” Nelson explained. Properly composted material can be spread over working fields to counteract soil erosion and increase the fertility of the fields. Well-managed compost can also provide income. “High-quality compost typically goes for $45 to $50 per yard. Farms can sell the abundance of compost they have and generate additional income,” he concluded.

Editor’s note: This article originally appeared in the February 2011 issue.

Nutrient and Manure Management and the Poultry Industry

rooster standing on top of the waste

Nutrient and waste management for your farm is just as important as your daily duties. With so many different alternatives for nutrients, it’s important to figure out which ones work best for you and your farm.

Fertilizer remains a tested and still-true-today method is land application. It contains Nitrogen (N), Phosphorous (P) and Potassium (K), along with other essential nutrients that are beneficial to growing crops, according to Dr. Amy Shober, Associate Professor and Extension Specialist at the University of Delaware.

Alternative uses for manure, she stated, include pelletizing, biogas production, and energy production which require on-farm treatment of manure or transport of manure off the farm.

“The appropriate alternative use depends on the manure system (e.g., liquid vs. solid), regional availability, and regulatory policies,” Shober said.

Shober mentioned the term “nutrient budgets” in her essay ( She described the term as a checkbook system by which a farmer can compare nutrient inputs to nutrient outputs.

“This is a particularly valuable tool for dairy farms, where the liquid nature of the manure makes transport of manure off-farm difficult,” she said. “A whole farm nutrient budget helps the farmer assess the potential for “farm-scale” surpluses of N and P, identify where nutrient inefficiencies exist and determine BMPs to reduce or eliminate the nutrient surplus.”

Another popular alternative use for nutrients is generating fuel, which saves farmers money.

“For the past six years, farms ended up going with this concept because it generates fuel that the farm would have to buy as propane,” said Paul Patterson, Professor of Poultry Science at Penn State University. “It generates ash product and nitrogen that goes up to gas. But, the valuable trace minerals such as phosphate, calcium and others are condensed into ash and represents 10 percent of the original weight.”

Where Does Poultry Fit In?

Poultry waste gets transported to watersheds where soils need P. More farmers are planting cover crops and adoption of irrigation is up, which allows for stabilization of yield, Shober noted.

While farmers can’t necessarily detect the Avian influenza virus (AIV) in poultry waste, they would be looking at flocks, said Patterson. The high pathogenic avian flu has three to five days death time.

“The farmers are with the birds every hour of the day, so they notice an increase in bird mortality,” Patterson mentioned. “The birds will be sampled for the virus and get the lab results back within 24 hours and then, they would all have to be euthanized. It’s like a fire emergency; we must kill the fuel before it spreads.”

After the virus has been detected in the birds, it’s important to manage the organic matter on the farm such as the manure, eggs and feed, according to Patterson.

The good news, however, is that the virus is weak outside the host, but under moist, cool conditions, it can survive outside of the host.

“Our strategy with manure is that we’ll burn it under about 140 degrees Fahrenheit for two heat cycles,” Patterson said. “If it goes through those two cycles, that’ll diminish the virus load and eventually there will be none.”

With the detection of the virus on a farm, the USDA quarantines the zone and disposes the birds along with any eggs.

Handling Manure and Nutrients

A farmer can store manure in covered stockpiles, open storage or temporary storage.

According to the Virginia Cooperative Extension, if the manure is to be stockpiled, it should be covered with at least 6-millimeters-thick plastic sheeting and held in place by weights.  For open storage, there are bunker structures that allows for “deeper piling and compaction of litter to reduce the total area required for storage.”

For another alternative, the Virginia Cooperative Extension recommended a roofed structure that allows for continuous loading or unloading with minimum effort.

“The egg industry evolved; now there are no more basements and manure doesn’t fall below the poultry cages,” Patterson said. “Manure is carried out on belts beneath the cages and the storage is at the back of a building on an automatic conveyer. We’re not storing manure in the same area where the birds are.”

Patterson mentioned farmers keep the birds safe and dry, which then can be managed to coincide with fertilizer.

Common Misconceptions

From a farmer’s perspective, a general misconception about nutrient management is that farming involves many variables like weather and economics, according to Shober. She mentioned that nutrient management planning is important, but sometimes, plans have to change to accommodate things that are beyond their control.

More specifically, popular misconceptions about poultry manure revolve around the idea that it’s toxic.

“The public has a perception that commercial agriculture is a big enterprise and birds produce toxic amounts of waste,” Patterson said. “In reality, the birds are properly housed with proper feeding for livability and performance. The structures are also properly engineered.”

According to Patterson, the properly engineered structures manage waste and dry manure systems, so they don’t use liquid handling. The manure is dry and doesn’t have an odor, so it doesn’t attract flies and it preserves nutrients that can be applied to land or a fuel source.

“The government and the industry working hard to protect the environment and the air quality,” he said. “People have the perception that it’s a big agricultural problem and that couldn’t be further from truth.”

Featured photo credit: iStock/dusanpetkovic