Are you taking your safety seriously when dealing with manure?

Hydrogen sulfide gas and foaming continue to be a serious issue in and around barns. But don't take my word for it. Hear Leon Sheet tell about what happened to him and why you need to take this issue seriously. Your safety is important to us and we are always humbled to hear our messages makes a difference. Hear Kris Kohl talk about his recent experience when a farmer told him about remembering hearing about hydrogen sulfide in training and how to react. We all on the manure team here at Iowa State feel the same way, and hope you take the time to educate yourself about ways to keep yourself safe and check out some of the resources below for altering you of H2S dangers.

Hydrogen sulfide is especially concerning when agitating or pumping the manure. As the amount of distiller’s grains in feed rations has increased, so has the amount of sulfur excreted by the animal. Over the past ten years, sulfur concentrations in swine manure have increased from 3 pounds per 1000 gallons to 9 pounds per 1000 gallons. When manure is agitated, hydrogen sulfide gas can be quickly released. Exposure to low concentrations of the gas for even a short period of time can cause health issues and at high enough concentrations can cause near instant death. A list of symptoms to different hydrogen sulfide exposures is provided in Table 1.

If you work around manure, monitors can be purchased to help keep you and your employees safe. A monitor, which is small enough to wear, ranges in cost from $99-$800 and will alert you if the situation is dangerous. This year as part of the manure applicators program participants were asked if they currently use any type of hydrogen sulfide monitoring equipment. On the commercial applicators survey, 5 percent of workers reported using a hydrogen sulfide monitor compared to 1 percent of confinement applicators survey. When asked about the likelihood of purchasing a monitor, 25 percent of commercial applicators and 31 percent of confinement applicators said it was likely that they would purchase a monitor (for a summary of this information see Figures 1 a and b below).

There are numerous options available for monitoring hydrogen sulfide levels when working with manure. Below are links to four meters for you to take a look at and some pictures of what they look like.

1. Honeywell GasAlertMax XT II
2. BW Honeywell GasAlert Clip Extreme GA24XT-H
3. BW Honeywell GasAlert Micro Clip XL 4-Gas Monitor
4. Draeger Pac 3500 H2S Monitor
5. RAE Systems ToxiRAE II

In addition to considering purchasing a monitor, other practices to follow when agitating or pumping manure include:

• Check to ensure all ventilation fans are working prior to pumping and that air inlets are open
• Place a tarp over pump-out to help protect the applicator
• Communicate with farmer and crew and never enter a barn during agitation and pumping
• Listen for pig distress
• Always be aware and alert as dangerous situations can develop quickly.

What does manure application cost?

What's it going to cost me? This seems to be a popular question these days, whether it be someone looking to compare different application systems (like tanks to umbilical systems) or just trying to figure out the value manure might have in their farming operation, determining costs are critical to developing the best manure plan for your farm. I won’t pretend to have all the answers, but what I do have is some data from 41 commercial manure application business provided us in the Fall of 2013 in response to a survey (three long years ago already so it might be time to start thinking about updating that) and a quick and dirty cost estimation technique.

So a few years back we asked commercial manure applicators in Iowa what they were charging to apply liquid manure (it could have been with an umbilical system, it could be with tanks I didn't ask what method they were using) and how that price varied with some different hauling distance. We have 41 business reply with responses (my best guess is there are around 550 commercial manure application businesses in Iowa, at least that is how many are currently certified). Fewer companies did give responses for the further distances - our response rate was: 1 mile, 41 responses; 1-3 miles, 38 responses; 3-5 miles, 25 responses; 5-10 miles, 11 responses, and greater than 10 miles, 4 responses). Within each distance category I calculated the average application price and standard deviation of the price.

The results indicated that at one mile the average price was $0.013 per gallon of manure applied. A regression equation fit the data well indicating that the manure application cost was about $0.01 per gallon and indicate that there would be a cost of about $0.0035 per gallon per mile the manure is hauled. Although this pattern generally held true there was greater variability in price at greater transport distances. A few comments, remember, these are approximate prices, actual price is also dependent on farm characteristics (application rate, travel path to the field, etc.), as well as the hauling equipment used.

Figure 1. Estimated manure application cost as a function of transport distance. Error bars represent the standard deviation in reported price.

An important question we can ask is what should we expect the relationship between hauling distance and cost look like? Another way of answering this question is to perform a 1^st order estimate of costs. I take a bit of time and came up with some of my best estimates of what it would cost. Scouring on-line I found a 5250-gallon manure tank for sale for $40,000 that I estimated I could get 5-years of use from, giving an annual investment (assuming 4% interest) of $8985. Assuming I’m applying about 1.5 million gallons a year (right around 300 spreader loads) this would be somewhere around $0.006 per gallon of manure in capital expense. The next step is to estimate some operating expenses. In this case I’m going to estimate about $50 an hour for fuel and lubricant costs for the tractor and $15 an hour in labor costs. The better you can estimate these numbers, the more accurate your price estimate will be.

I then went about figuring out how different hauling distances would change my productivity, i.e., the flow rate I could achieve with this tanker at different hauling distances. To get an estimate of operating costs I assumed it would be 4 minutes to position the spreader at the loading platform, 8 minutes for loading, and 8 minutes to unload in the field. Travel time to and from the field accounts for the remaining time; to calculate travel time I assumed a speed of 8 minutes per mile. If you use these assumptions and plot the cost of manure application as a function of transport distance you get a roughly the cost function that we found empirically from our survey. Again note, that these estimates of loading, travel, and emptying time can have a big input on cost; the number I chose are a good first estimate but should be tailored to your equipment for a better estimate.

Figure 2. Calculated manure application cost as a function of transport distance based on the above example.