Features
Show litter some love

Poultry manure (litter) is an increasingly valuable nutrient source. Because poultry farmers now stand to make more from poultry litter than before, best management practices are key to assuring maximum profit while retaining nutrient value.

Shawn A. Hawkins, professor and extension specialist, biosystems engineering and soil science, University of Tennessee explains that the majority of the birds produced in his state are broilers. “They’re raised on an open floor, usually with some type of bedding,” he says. “We produce successive flocks on that dirt floor, and we get a buildup of litter that is managed in different ways.”

Hawkins says that the litter ends up as a mixture of a number of components: spilled feed, manure, the used bedding, and feathers.

Litter storage
While litter storage is an option, and one that many poultry farmers will find practical, Hawkins recommends using litter right away. “Rather than store it, you want to remove it at the time when you have crop demand, and directly land apply,” he says. “That’s the best approach.”

If applying the litter immediately isn’t an option, the good news is that storing litter won’t significantly impact its nutrient value. “The losses during storage are frankly pretty small,” says Hawkins. “Now, I’m not suggesting that you could take this material and store it for years. That would not be a good practice, because some of the moisture content is going to be lost, and the nitrogen content will be reduced.”

The vast majority of the nitrogen is associated with organic compounds, Hawkins adds. “That material has to be broken down in the soil to become plant available, and it’s fairly stable when it’s stored,” he says. “The ammonia of course is not, but that’s a minority of the total nitrogen that’s in the litter – perhaps, on average, about 15 to 20 percent. So that material is prone to being lost during storage, but it’s not the majority of the nitrogen that’s present in the litter.”

In other words, nutrient loss is not a big issue with litter, except if it’s stored too long or in the wrong environment. “There isn’t a mechanism for nutrients to be lost during storage, especially if the litter storage building has a roof,” explains Hawkins. “It would be different if the material was stored in the field for many months at a time, which is not a good practice. And you can have losses of potassium when litter is field-stored for quite some time.”

Rising value of litter
Storage is not an issue for poultry farmers in Tennessee, says Hawkins. “Our bigger problem is that there’s a large demand for the litter by row crop producers in our state,” he says. “The issue is that everyone wants the litter, all at the same time.”

The high demand for litter translates into higher costs for those who want to purchase it. It also means that the litter supply can be exhausted before all the demand is filled, which is why some farmers have to do without. “That’s the scenario that is most common in West Tennessee right now,” he adds. “We have more demand for the litter than we can actually supply.”

The old laws of supply and demand certainly apply to litter, which means that the prices for litter have gone up in recent years. “The value varies with fertilizer prices,” explains Hawkins, “and it has gone up dramatically.”

He adds that in areas where demand is high in Tennessee, the price might be $50 per ton. “And if you were to go in and do your evaluation, based on your litter analysis, you’re going to see that obviously, the litter has more intrinsic value than $50 per ton,” adds Hawkins. “But you’ve got the cost of transportation and applying it, which can be pretty significant.”

In areas where demand is low in Tennessee, it’s not unusual to be able to get litter for half that price. “As you move east in Tennessee, where more and more of the of the litter is going on pasture and hay fields, the value of the litter is significantly reduced,” says Hawkins.

The $25 to $50 per ton price for litter today in the state of Tennessee, as an example, is much higher than it was even a few years ago. “If we go back five years, it would not be unusual to get litter for $15 a ton, particularly in east Tennessee,” adds Hawkins.

Litter broker
Knowing that the price of litter is high in one part of a state, and lower in another, some enterprising individuals have decided to buy low, load the litter onto a truck, and sell high in another part of the state. “I talk to producers every year who transport dry manure and litter products, but frankly, I’m not sure it adds up once you consider all the costs,” says Hawkins. “A good rule of thumb: Don’t move litter more than about 10 miles.”

A common practice in Tennessee, according to Hawkins, is poultry producers using a third party to clean out the litter. “A lot of our newer farms do not have litter storage buildings,” he explains, “so they will rely on what we call a litter clean-out service. They, in effect, become a dealer/broker for the litter: They trade the clean-out service for the litter itself, and then they make a profit by marketing the litter to producers who are interested in using it as a fertilizer.”

Storage options and fire hazards
How litter is stored will affect its value and nutrient content. As with all things, there is a good, better, best scenario. “The worst is long-term field storage, where you do not have the material covered with a tarp or in a storage building,” Hawkins explains. “I would not say that’s common, but I do see it occasionally.”

The better option would be to store litter in a dedicated litter storage building, and then time the removal of the litter with the nutrient demand by local farmers. Hawkins says that these buildings commonly have concrete floors, but not always. In Mississippi, for example, dirt floors are common. A roof typically covers the structure, and the buildings have to be well ventilated.

“Many of our litter storage barns don’t have open sides,” he adds. “They have a covering on the sides of the building that prevent windblown rain from getting in and wetting the stored letter.” Mixing dry and wet litter can lead to fires (more on that below).

“And then the best practice, in my opinion, would be if a row crop producer had neighbors that had barns, then they would ask when they’re going to be removing litter,” adds Hawkins. “They would then apply the litter directly. In other words, they would remove it from the house and take it straight to the field to land apply within four weeks of planting a crop that has a high nitrogen demand, such as corn.”

A key concern with litter storage is the high possibility of fire. Hawkins warns against stacking litter too high, because litter storage buildings are prone to fire when the litter is stacked too high.

“I’ve witnessed it probably a dozen times in Tennessee,” he says. “These buildings are sized based on the production rate of litter, and then they’ll size them based on the density of the litter, assuming that you’re not going to stack the material more than six or seven feet high.”

Stacking the litter higher than six or seven feet can lead to overheating, which in turn can cause spontaneous combustion. “If wet litter is stored next to dry litter,” Hawkins explains, “that interface will be where spontaneous heating begins. The high bacterial activity within the litter itself begins, and then it becomes a runaway biochemical process. So the reason we recommend not stacking the litter too high is to limit the amount of mass that you’re accumulating so that there’s more dissipation of that heat.”

This is also why it’s important to cover the sides of the building in order to prevent  windblown rain from wetting the litter, which would also create an ideal environment for bacterial activity, leading to overheating and fire.

If producers cram the litter into a building, stacking it 10 or 12 feet high, that can lead to trouble, explains Hawkins. “There’s more mass there for heat retention, and that’s when it’s a problem,” he adds. “I’ve seen numerous storage fires over the years, not just in Tennessee, but in other states as well.”

Hawkins concludes with a warning to all managers of litter buildings: “I wouldn’t say that fire is uncommon. It’s a problem to be expected if litter is not stored properly.”

Properly collected and properly stored, litter can offer poultry producers a sizeable return, especially now that fertilizer prices have increased dramatically. •