Monday, October 27, 2014

Economic Value of Manure Sampling and Testing

As you may recall, last week we talked about a bit about manure in relation to precision farming. We said there are really three aspects to precision farming, measuring something, making a decision based on that thing we measured, and then implementing our decision. Today we are going to look at these concepts in terms of manure management, specifically in terms of manure sampling and testing.

To start with we need to understand a little bit about manure. One of the most common questions asked about manure “what is the fertilizer value of manure.” This question usually means, “How much nitrogen is in the manure?” or stated a slightly different way, “how much manure should I apply to fertilize my crop?” This question doesn’t have an easy answer, because unlike commercial fertilizer (anhydrous ammonia, MAP, DAP, or urea) we might usually purchase, manure doesn’t come with a guaranteed composition. Instead, there can be substantial variation in nutrient content from one-farm to the next, year-to-year on the same farm, and to a lesser extent the manure that we are pumping out during a single land application event. This variation makes “book values,” i.e., estimated nutrient contents available in Midwest Plan Services or state extension materials a good starting point for planning purposes, but means that we really need to measure the nutrient content of our own manure to understand what is in it.

One way to think about this is based on probability. This is demonstrated for a swine manure from a deep-pit manure storage in figure 1 below. What you see is that the manure has the greatest probability, or the highest chance of having at a nitrogen content of 7 kg/1000 L (or right around 58 lbs. of Nitrogen per 1000 gallons of manure). However, what’s harder to tell is that there is something like a 20% chance that swine manure might have more than 9 kg N/L (75 lbs./1000 gallons) or a 20% chance that swine manure will have less than 5 kg N/L (41 lbs./1000 gallons). This means if we were basing our manure application off “typical” or average swine manure and trying to applying 150 lbs. N/acre, there is a 20% chance we apply more than 190 lbs. N/acre and a 20% chance we apply less than 110 lbs. of N per acre. So what does this mean to us? Well, it implies there is a pretty good chance we won’t be applying the amount of nitrogen we think we are. This is costing us lost revenue from either not fully utilizing our N (if we end up applying more nitrogen than we need) or from nitrogen limitation in our crop growth (if we are applying less N than we think we are).

Figure 1. Probability or a swine manure from a deep-pit manure storage having different nitrogen contents.

Based on this I think we have an interesting question we can ask ourselves, and that is, what is the return on investment of manure sampling. That is, how much value does manure sampling add to our operation? In determining the value of the manure test, it is important to understand how a farmer can use the information gained from the test results, i.e., how having this information alters the farmer’s nutrient management and affects the farm profit. This is a complex topic, as almost limitless possibilities exist, but to get a general idea I’m going to make a few assumptions and approximation about common cropping and manure management systems in the Midwestern United States. This may mean the results don’t give you an exact value for your operation, but they give you a pretty good starting point.

In this evaluation, I assumed that the manure application method would be either injection or immediate incorporation to maximize N utilization. Additionally, I assumed that best management practices for manure application timing were followed; as a result, the yield response to available N (defined here as the sum of ammonia N and organic N expected to mineralize in the first growing season) would be the same as the yield response to mineral N fertilizer. Finally, we limited crop rotation choices to continuous corn and corn-soybean rotations, as these represent the dominant rotations in the upper Midwestern U.S. The impacts on the value of the manure test of N-limited or P-limited application, as well as when sampling or testing was conducted, were handled by evaluating all cases. Finally, the basis of this effort was that farms intend to use their manure resources to support crop production. In cases where farmers have insufficient land to use all their manure resources, they can only extract the value of the manure test if they can find buyers for the manure nutrients.

The value of the manure test was calculated by estimating the profit that would have been made if the manure was assumed to have a “typical” nutrient composition and then to compare this to the profit generated if the actual nutrient composition was known. The profit graphs for these steps are shown in figures 2, 3, and 4. As a note, I performed this analysis earlier this spring when corn price was $5 per bushel.

Figure 2. Probability of different profits due to different nitrogen contents of manure assuming manure standard rates.

Figure 3. Expected profit from applying manure of a known composition at the maximum return to nitrogen (rate changed to account for measured nutrient content).

Figure 4. Expected value of the manure test, based on graph 3 minus graph 2 (adjusted based for sampled manure nutrient content case minus assumed nutrient content case).

To put these results in perspective I used the model to evaluate what manure sampling would be worth for a 1000-head capacity swine finishing farm using a deep-pit manure storage. On average, the facility generated 4 L of manure per head per day. This farm has collected and tested manure samples every year for the last five years. The first four years of manure sample values were 0.84%, 0.72%, 0.98%, and 0.62% N, with an average and standard deviation of 0.79% ±0.16% N. The N content for the current year was 0.92% N. If no sample was tested, this operation assumed that the manure had an available N content of 0.79%, the average of the previously collected samples. Using pre-application sampling and assuming that manure application was N limited, the value of the manure test would be $30.96 ha-1. Assuming that the manure sample is representative of all the manure from this building, the overall value of the sample was $1,759 (the farm would have applied manure to 56.8 ha). This represents a good return on investment, as the approximate cost of obtaining this information would be $50 for manure testing, $50 for shipping the manure to the testing lab, and $100 for the farmer’s time to collect, label, and ship the sample, giving a return of almost 9:1. If manure application was P limited and manure was sampled during application, the estimated value would be $14.20 ha-1. In this case, the manure was applied to 112 ha, so the actual value of the test would be $1,589

The same analysis was performed for other manure types and estimated values of manure testing are shown in table 1.Overall, the results indicated that sampling and testing the manure provided enough economic value that it would pay for itself.

Table 1. Estimated value of the manure test for different manure type and crop rotations.

Monday, October 20, 2014

Precision Farming and Manure

Recently, I have been hearing a few buzzwords (precision agriculture, big data, and even precision conservation) that really got me thinking about what these ideas mean in terms of our manure management. Often times when we hear the word precision agriculture it brings to mind the newest equipment being controlled precisely to drop a seed exactly where we want it. While I think this is an important part of precision agriculture, to me at its heart it is all about providing site-specific management practices within our fields to improve our crop production and lessen impact on the environment. This means we need innovative ways to understand our agriculture decision and then methods to take this information, determine an optimum way to move forward, and then implement the management practice we determined would work the best. I break it down into three important steps – measurement, decision-making, and implementation.

The first two steps, measurement and decision-making aren't always what gets the most glamorous, but they are probably the two most critical steps, and this is really what the new buzz term “BIG DATA” is. In agriculture, there are all kinds of information available at our fingertips: market prices, weather forecasts, soil types, planting population maps, past yield maps, or maybe even aerial photos of what are crops currently look like. This means there are many pieces that we need to take into account as we try to make a decision about our best course of action on what we should do to “get the most from our field.” In many cases, we rely on our experiences in similar situations to make our decision based on our current condition.

 I like to think of this in terms of sports, practice and then do. I don’t know if any of you are basketball fans, but with the season starting up again I thought this would be the perfect chance to mention it. You may recall last years’ NBA finals pitted the Lebron led Heat against the Spurs, but here I’m going to focus on the a mall moment earlier in the Spurs season. Spurs down by 2, 9.5 seconds left, Spurs ball… Park takes the ball and using a Duncan screen attacks from the left wing for a layup, but at the last second sends a pass to Leonard on the weakside for a corner three, which of course he makes for the win. Why did this happen? Well, of course practice and experience, but at a more data driven level (good old sabermetrics) we know corner threes are the best shot in basketball (most points per attempt, but corner threes are typically assisted) so the Spurs drew up a play to give them the motion to get one of their better shooters into this position. Did it mean it would work? Of course not, but it gave them the best chance to succeed. Precision agriculture is the same thing, it might not always work like we wanted, but it’s the idea of putting us in the best chance to succeed.

So how do these precision concepts fit with the world’s oldest fertilizer, manure? Well, in the long run it may mean trying to implement more site-specific manure management practices, but in the short run it means making sure we are getting the right data to inform us and then using this data to make decisions. When I think of this “precision ag” concept in terms of manure nutrient management, there are really four basic steps/or principles. 1. Measure the nutrient content, 2. determine the application rates needed, 3. control the rate applied, and 4. produce a record of where and when that application occurred.

Many factors cause variations in the nutrient concentration of manure, including diet, housing type, manure storage type, environmental conditions, management techniques, and treatment practices. Given the variability in composition, manure sampling and subsequent testing for nutrient composition is a critical component of proper management. For example, while “book values” are reasonable averages, they are just that, averages, they don’t represent your farm. It’s not uncommon for one farm’s manure to vary by 50% or more different from that average manure. For example if you asked me what I thought was the typical nutrient content of swine manure I’d probably say something like 50 lbs of N/1000 gallons, but I look at sample results all the time that have 60, 70, or even 75 lbs of N per thousand gallons. This means we can get a big financial advantage if we can manage to make the best use of these manure nutrients.

Next time I’ll provide you will some more details on how to use the results of manure sampling and testing and provide some insight into the economic value this decision making might have on your farm, but for right now I just wanted to make you aware of some resources on how to collect a good manure sample. The resources is “How to Sample Manure for Nutrient Analysis” and you can find it at

Monday, October 13, 2014

What's that smell? LECA as a Permeable Cover for Manure Odor Reduction

Manure - we all know that it provides some great nutrients that can help support crop production, but even its most adamant supporters will recognize that in some situations is can have a smell. Here I'm going to provide a short discussion on the science of manure odor and then discuss one specific management practice, the use of LECA as a permeable cover on a manure storage, that can be used to mitigate odor in some situations. The use of LECA is by no means  the only option, it only receives highlighting here due to a recent question I received about its use. More information on the use of LECA as well as other permeable covers can be found at, while information about other odor and greenhouse gas mitigation options for animal production systems can be found at

Manure odor chemistry is complex, there are more than 400 gases that contribute to the odor, but generally the majority of the odor comes from just a few gases, including ammonia, hydrogen sulfide, cresols, volatile organic acids, and amines. These compounds all can result from the partial decomposition of organic matter in the manure. These compounds are natural byproducts of anaerobic breakdown of the organic material in the manure. To be perceptible as odor, these compounds must escape from the liquid phase and be present as a gas. The release of these compounds is impacted by factors such as the compounds vapor pressure, solubility, the manure's pH, or even if a  crust is present on the manure preventing release of these compounds. Most of our developed mitigation techniques try to adjust one or more of these properties to prevent the release of the odorous compounds.

One option that is sometimes used for odor control is permeable covers. Permeable covers are materials that lie directly on the surface of the stored manure and provide a physical barrier between the manure and the surrounding air. Examples of permeable covers include natural crusts, layers of natural vegetative materials (such as straw, corn stalks,ground corncobs, etc.), vegetable oils, permeable fabrics (geotextiles), as well expanded clays, ceramics, and ground rubbers (examples include LECA and Macrolite). The success of permeable covers depends on achieving season-long floatation and continuous 100% coverage of the manure storage structure, in this post we'll focus on LECA.

LECA is a light-weight expanded clay aggregate. It’s basically a ceramic shell with a honeycomb core produced by firing natural clays at 1100-1200C in a rotating kiln. The bulk density of 8-12 mm diameter LECA is about 325 kg/m3, allowing it to float. It is highly durable to both chemicals and frost giving it a long life (10 + years). LECA covers are typically applied in a 2 - 4 inch layer to provide good coverage of the manure. LECA is one of the highest cost of permeable covers and has been hard to obtain. (The LECA that I can generally find is still from European companies.) Below, is a picture of LECA.

Below is an example of an in-ground circular concrete tank swine manure storage that has a LECA cover. This LECA had been in use for over 10 years and provided a coverage depth of about 3-4” on the manure surface. Occasionally the LECA would all drift to one side of the manure storage from wind blowing from the same direction continuously, but it would generally fix itself after the wind direction switched. One potential issue with expanded clays is that agitation and pump out must be conducted in a way that ensures the floating cover material is not removed from the storage. This can generally be performed with minimal changes to standard agitation and pumping practices.  Such as corralling the LECA away from pump inlets or providing screening so the LECA cannot go through.

LECA works in a manner to any permeable cover (like chopped straw) in that it provides a barrier that helps reduce wind disturbance of the manure surface and in doing so lessens the transfer of ammonia, hydrogen sulfide, and other odors into the air. That is the permeable cover shields the manure surface from contact with the air. The major advantage of LECA over a material like straw is that the LECA has a long life, it is basically inert, so it lasts for a long time. When you are using LECA as a cover you are generally trying to get a 2- to 4- inch thick layer on the surface, and it generally is management free except when you are trying to pump the manure.

As far as studies of its performance there have been a few, but they mainly come from Denmark as this is where most of the LECA is made, but they generally show somewhere around a 50-90% reduction in odor, 60-80% reduction in hydrogen sulfide, and 70-90% reduction in ammonia, with performance varying a bit based on how well the manure stays covered and the thickness of the LECA cover. Thicker covers generally due a little better, but performance doesn’t increase that much as long as about 1.5-2 inches are floating on the surface. The problem has generally been that every square foot of manure storage you are covering costs something like $1-3, which adds up pretty quickly (this price is actually pretty comparable with what some impermeable covers would cost to purchase and install).

Although I haven’t seen in agricultural settings, a similar in concept and has me intrigued is the use of circular plastic balls. The balls float on the surface and act very similar to the LECA in covering the surface. There are a few companies settling these types of plastic module balls to municipal wastewater treatment plants, the challenge would again be how do they hold up in agricultural manure storages and do they interfere with our typical agitation and pumping practices?

Thursday, October 9, 2014

What is the economic value of manure?

Thinking about selling your manure?

There are several versions of pricing for selling swine manure; they range from having to pay to get rid of the manure, getting reimbursed for the cost of hauling, on up to charging for the manure. The pricing method chosen is generally related to how in-demand the manure is, or alternatively, how hard it is to get surrounding farms to accept the manure and the amount of manure that is available. In general, over the last few years we’ve seen more farmers wanting to take the manure for use in their crop production systems due to higher costs for commercial nitrogen and phosphorus fertilizers.

One resource you may find useful is "Value of Manure Nutrients." This is available at and is part of the Ag Decision Maker tool. Although this article was written in 2007, many of the pricing factors remain similar. This tool provides a spreadsheet  that can be used to estimate a price for the manure for swine operations.

I’d suggest that the most common  method of valuing swine manure as a fertilizer is using component pricing. The manure is sampled and tested to determine the nutrient content and the nutrient content is then used to determine the value of manure based on commercial fertilizer prices. For example, a typical swine manure might test around 50-35-25 pounds of N, P2O5, and K2O per 1000 gallons (typical is always a challenging word as there can be large variation between farms and even from year-to-year on a single farm due to differences in diets, barn management practices, water wastage, and other factors). Assuming a corn soybean rotation a common application rate of the manure might be around 3,000 gallons an acre (I’d estimate that to supply 147 lbs of N per acre at this nitrogen content, which is very close to the maximum return to nitrogen -

At the current time I have anhydrous ammonia priced at $726.14 per ton, Potash (red) at 476.75 per ton, and MAP at 605.25 per ton. Based on this I have nitrogen selling for $0.44 per pound, phosphorus (P2O5) for about $0.49 per pound, and potassium (K2O) at $0.40 per pound. Based on the example I’ve been using the manure would have a component value of about 50 lb N/1000 gallons*$0.44/lb N  + 35 lb P2O5/1000 gallons*$0.49/lb P2O5 + 25 lb K2O/1000 gallons*$0.40/lb K2O = $49 per 1000 gallons of manure.

Depending on who is covering the cost of land application you’ll either want to sell if for this price (if you are covering the cost of land application) or this price less the cost of land application (about $0.02 per gallon or $20 per 1000 gallon, so about $30 per 1000 gallons) if the person buying the manure is covering the cost of land application.

There are a few caveats to this analysis, the first being that as you mentioned sometimes we see an extra yield bump when we use manure. This may be due to the sulfur, iron, organic matter, or even other factors such as increased microbial activity or the additon of other trace nutrients. This pricing method wouldn’t put value to this extra yield benefit, which is probably fair since it is hard to quantify and predict. A second caveat is that manure comes as a package fertilizer, that is we get both the nitrogen, phosphorus, and potassium all together. However, the person buying the manure might not really want or need the potassium or phosphorus, this would make these components less valuable to the person buying the manure, i.e., they might be worth less than current market price. This depends on the specific cropping situation and current soil test levels in the field that will be receiving the manure (unless the soils P and K levels are already in the high or very high range, the component pricing method is probably close to fair).
The final issue is that there is some extra hassle when dealing with manure, such as the odor of land application (may or may not be an issue depending on field location compared to houses in the neighborhood and the person buying the manures perception of the odor level), the potential variability in manure nutrient content, compaction issues that could be caused by the manure application equipment, or challenges with timing the manure application. These factors can slightly lower the value of the manure as it sometimes makes some farmers less willing to utilize the manure.

In the end, I think the component pricing method less the application costs provides a pretty good starting point for any negotiation on what manure is worth, but some adjustments are probably required to offset some of the other challenges (odor concerns, not have N:P levels balanced to crop need, variability in nutrient content) to provide some incentive for choosing manure as compared to commercially available fertilizers. In the end, manure is like any other bulk commodity, its market price will be depend on the supply in demand. This means that perceptions in your neighborhood about manure and the willingness of neighboring farms to accept (or even desire) the manure along with how much manure is available are important in setting the price.

Monday, October 6, 2014

Preparing for Fall Manure Application

It seems another fall has arrived, and with it another crop harvest. Though this time of year is busy with numerous activities, it is also one of our primary manure application periods. To make sure you are ready, begin preparing for manure application now. This will allow you to streamline the process and helps insure proper nutrient application rates. To ensure you are getting the most from your manure resources we have the following tips:

Collect a representative manure sample and submit it to a certified lab for analysis of major crop nutrients. Taking manure samples prior to land application provides nutrient analysis results for planning application rates and is recommended if applying at a nitrogen limited rate; sampling during application can be used to determine the actual amount of nutrient applied. Use your nutrient analysis results to determine the appropriate application rates for each field based on the nutrient needs and current soil conditions.

Prior to beginning land application, review your manure or nutrient management plan and make necessary updates. In particular, pay attention to the application methods and separation distances specified for each field. Review these with your employees and/or commercial manure applicators. Know and follow land application separation distances from neighbors, public use areas, and water sources. Map these out on aerial photographs of your fields, clearly designating areas of potential concern, special features, and areas to avoid when applying manure. Train your employees and commercial applicators to read the maps and stay clear of the designated areas. Check to be sure your (and your employees) manure applicator certification license is current. If you find your license has expired contact your local ISU Extension office to schedule an appointment to attend training. If you are not sure of your current applicator certification status contact the DNR Licensing Bureau at 515-281-5918.

Inspect your manure handling and application equipment. Make sure it will be ready and function correctly. Replace or repair anything that needs to be fixed to prevent leaks and spills. Don’t forget to check your safety lights and the slow moving vehicles signs as well. Repeat these checks daily throughout your manure application season. Take the time to calibrate the equipment so you know what you are applying. Would you be satisfied if a co-op did not know how much nutrient they were applying? Of course not, treat manure the same way. Calibrating may take a little time, but the effort will increase your ability to take advantage of your manure resources. With ammonia rich manures, try to delay application until soil temperatures are 50°F and cooling. By waiting for cooler soil temperatures, the applied ammonia will have a better chance of being retained in the soil and benefit crops next spring.

Do you have your emergency action plan ready? There are no simple solutions for manure spills, but thinking through your specific situation and having a plan in place minimizes the environmental and safety risks. Check over your existing emergency action plan, update it, and review it will all your employees to make sure they are ready to respond if the need arises. If you are hiring a custom applicator, ask to see their emergency action plan and make sure it is appropriate for your farm. Keep lists of important phone numbers and contact information for excavators, neighbors who can help, DNR field offices, and emergency response units up-to-day and posted where everyone can find them. Manure spills happen; being prepared to respond to them will help protect water quality. Similarly review your biosecurity protocols. Manure can serve as a transport vector for many animal diseases including PEDv. Good biosecurity is not supposed to be easy, it will be inconvenient, but it’s worth it. Communication with your application crew about biosecurity practices both prior to and during the manure application is key. Beforehand make it clear what your biosecurity expectations are and learn about the precautions they are taking. During application, maintain a line of separation and offer a water source away from the barn for equipment clean-up. Follow-up afterwards about what worked, what didn’t, and how to improve biosecurity the following year.

The number one complaint about manure application is the odor. Work with your neighbors to let them know about your manure application plans. If possible tell them how long it might take, how long you plan to apply the manure, and how long they might expect to smell the manure. Inquire about any outdoor events in the neighborhood and try to avoid applying during or just prior to these activities. This might seem like a lot of effort, but in many cases an ounce of prevention is worth a pound of cure.

Finally and most importantly, be safe. Fall is a busy time of year, often leading to long hours and rushing to get things done. Take the time to get some rest, take breaks, and slow down. Happy hauling and be safe. 

How much manure is there in Iowa?

Manure Nutrient Availability Relative to Crop Nutrient Capacity in Iowa:
How much manure is there?

A common question about manure management in Iowa is how much of our land is receiving manure. This question is often asked after hearing statistics like animal farms in Iowa produce nearly 10 billion gallons of manure per year, or the pollution potential of animal manure in Iowa is the equivalent to that of 45 million people; 15 times the state’s current population. Comments like these often lead to thoughts of manure piling up, farmers doing everything they can to get rid of manure, and insufficient land on which to apply the manure. However, what is the truth behind these numbers and what does the manure situation in Iowa really look like? Over the next few paragraphs, we will take a closer look at these issues.
Data from the 2012 census of agriculture was used to estimate livestock populations and production within each county. Available nutrients in manure were calculated by estimating average animal populations and multiplying this value by a manure production coefficient, a manure capture coefficient, the amount of nutrient expected to remain in the manure after storage, and finally the percent of those nutrients that would be crop available. These calculations were performed for both nitrogen and phosphorus.
The nutrient assimilative capacity of cropland was estimated by multiplying the amount a crop produced in 2011 times the nutrient content of that crop. This is a low estimate of actual crop need as it only considers nutrients exported with the grain (about 0.8 lb N are removed per bushel of corn harvested).Additionally, nitrogen requirements for production of soybean or alfalfa were not included. These plants are both legumes, meaning that can obtain some of their nitrogen from the air; however, research has shown that these plants tend to use nitrogen available in the soil first and in some cases may require supplemental nitrogen to achieve desired yields.

Figure 1. Schematic of nutrient budget on an integrated farm. Our goal is to convert as much of the nitrogen, phosphorus, and potassium in the inputs into managed outputs as we can so that losses to air, groundwater, and surface water are minimized.

As you may be aware, there is considerable livestock production in Iowa as it currently leads the nation in both swine and egg production, is in the top ten in beef and turkey production, and twelfth in dairy production. All these animals result in the production of over 50 million tons of manure, 325,000 tons of available nitrogen, and 82,000 tons of phosphorus annually. Although this may sound like a lot, it took almost 1 billion tons of nitrogen and 220,000 tons of phosphorus to support the growth of corn and soybeans in Iowa in 2011. This means that only about 30% of our nitrogen and phosphorus needs for crop production could potentially be supplied with animal manures.
In terms of crop acres receiving manures a few more calculations are required. In Iowa, all confinement farms with over 500 animal units are required to submit a manure management plan to the Iowa Department of Natural Resources. Procedures in this plan specify how to calculate the maximum amount of manure that can be applied to a field. Based on the Iowa DNR requirements, the 325,000 tons of nitrogen from manure would be enough for about 3.8 million acres of corn per year. In 2012, there were 13.7 million acres of corn harvested in Iowa and another 9.3 million acres of soybean. This means only about 17% of Iowa’s farmable acres received manure in any given year.
This paints a far different picture than what we might imagine when we first hear about the amount of manure within the state, at it certainly indicates that their is plenty of land available to use all our manure as the nutrient resource it can be. However, as animal production is not uniformly distributed across the state, a closer look at county level nutrient balances is also of interest. This was done by comparing the estimated amount of available manure nitrogen and phosphorus to the crop nutrient assimilative capacity within that county.
In figure 2 and 3, counties that are various shades of green receive less than half their nitrogen or phosphorus needs from manure. As counties become progressively more yellow and then red they are capable of getting more of their nutrient needs from manures. In looking at these results, it is clear that the majority of counties have sufficient need for the nitrogen and phosphorus in the manure to make it a valuable resource in those counties. Although, these results provide insight into the current manure situation within a county, it should be recognized that they are sensitive to the assumptions made about both manure production and crop nutrient needs. Of particular concern, crop production in 2011 was somewhat suppressed, in south and southeastern Iowa, due to drought conditions. Additionally, these results assumed no manure would cross county lines, this assumption is most certainly not the case as some farms would be located near county boarders. Moreover, in many cases manures can be moved sizeable distances if it allows better capture and use of the nutrients it contains. For example, liquid swine manure can be moved around seven miles and still be a more cost effective fertilizer than purchase of synthetic nitrogen sources. Solid manures such as poultry litters can often be moved even further since they are more nutrient dense.

Figure 2. Available manure nitrogen as a percent of nitrogen removed with crop harvest.

Figure 3. Available manure phosphorus as a percent of phosphorus removed with crop harvest.

Friday, October 3, 2014

Welcome to The Manure Scoop

The Manure Scoop

Hello and welcome to my blog, The Manure Scoop. Within this blog I'll try to deliver timely information about manure management, treatment, and land application, as well as other manure issues relevant to Iowa.
Some of the information will be geared at helping you maximize the use of your manure as a resource for crop or energy production, while at other times I'll focus on how different decisions can impact soil, water and air quality for better or worse. Finally I'll try to give you a flavor of what the future might hold and the technology that is changing the way we think about animal agriculture and manure management.

Now for a bit about me. I'm currently an assistant professor and extension specialist at Iowa State University, where my work focuses on animal production systems, especially their manure. You might by thinking why would someone want to work on manure, that sounds like a dirty job, and at times you'd be right. Working with manure certainly has its challenges, but what doesn't, and just as importantly the use of manure offers a chance to improve our use of a great natural fertilizer and improve farm sustainability. Growing up on a small dairy farm in central Wisconsin I had the opportunity to experience first hand some of the benefits of utilizing manure as well as some of the challenges we face in our manure utilization decisions.

So as we look forward in the coming weeks and months I hope we have a chance to get to know each other and you find some information here useful. If there are certain things you would like to hear more about or you have any questions please feel free to leave them in the comments section below and I'll do my best to get them answered in a timely manner.