December 10, 2009

Delayed harvest has producers scrambling to apply manure

"The best time to apply postharvest manure is after the soil temperature cools down, and ideally when soils are dry," said Tamilee Nennich, Purdue Extension dairy management specialist. "Once we start having freezing soils and snow cover, application of manure needs to stop because of the greater potential for manure run-off. During this time it can be especially risky."

Even before soils freeze, there are still risks with fall manure application - especially when there is excessive soil moisture.

"The biggest concern about applying manure in the fall is wet soils," Nennich said. "We want to make sure that manure, and especially the nutrients in the manure, stay in the soil."

Because this fall has been so wet, Nennich said field selection is key when producers look to apply manure.

"It's made it really challenging for producers to get out in the fields and to actually find dry enough fields and the time to be able to apply the manure," she said. "Producers should apply manure in the fields that are the driest and have the best drainage. They need to make sure not to apply manure to fields with an abundance of wet spots or where runoff is more prevalent."

Another factor producers can look at is the nutrient value of the soil in each field. It's better to apply manure where soil nutrient levels, especially phosphorus, are lower.

For farmers with fields that are not suitable for manure application right now, one option to consider is whether neighbors might have fields better suited for application.

"Manure is expensive to haul and it's best to keep it close to home, but farmers need to take a look at their fields," Nennich said. "Sometimes it is better to haul it to a field that is farther away, or, in some cases, it might be a good idea to talk to neighbors. Maybe some of their fields would actually be better for manure application."

Once fields are selected, producers need to keep in mind the precautions they can take to keep nutrients in the soil.

"A lot of producers inject manure," Nennich said. "That's a great way to make sure the nutrients stay in the soil. If manure is spread on the soil surface, it provides a lot more opportunity for nutrients to run off. So incorporating manure instead of leaving it on the surface is very advantageous.

"Producers also need to pay attention to buffer areas, and if there are any sensitive areas, like low spots, avoid them. If it's possible, leave even greater buffer distances, especially in areas with down slopes, to try to prevent run off."

Nennich also suggests that farmers consider capping tile drains so nutrients don't leach out through the soil and potentially end up in surface water.

Even when field selection and the necessary precautions are kept in mind, the time crunch to empty manure storage facilities is presenting producers with concerns.

"It becomes a challenge because manure storage facilities do need to be empty going into winter because oftentimes six months of storage is needed before manure storage facilities can be emptied in the spring," Nennich said. "If we have a wet spring it can also be challenging to get into fields."

For farmers who have done all they can but still face serious storage issues, there are few options available.

"The reality is that it's a tough situation because there's not a lot that can be done about it," Nennich said. "Manure has to be contained one way or another. So, it either needs to be applied correctly or contained in a manure storage facility. Having a spill is extremely serious, so we need to make sure we prevent that from happening."

One agency that can help farmers is the Indiana Department of Environmental Management (IDEM).

"I would encourage producers to contact IDEM in difficult situations," Nennich said. "They have an agriculture liaison who will be more than happy to work with producers to discuss various options. It's definitely better to work with them to make sure they are aware of your situation and know that you're doing the best you can to manage your manure properly."

Writer: Jennifer Stewart, 765-494-6682, jsstewar@purdue.edu

Source: Tamilee Nennich, 765-494-4823, tnennich@purdue.edu

Ag Communications: (765) 494-8415;
Steve Leer, sleer@purdue.edu
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