Fall Manure Application: Part 1 Nutrient Management Plans

Nutrient management plans are important to have and follow, especially with this wet fall season. In this episode, we will discuss nutrient management plans, why they’re important, and other tips to help you this fall with manure application.


Liz Binversie, Agriculture Educator, Brown County UW-Extension


Carrie Laboski, Soil and Fertility Management specialist, UW-Madison and UW-Extension

George Koepp, Agriculture Agent, Columbia County UW-Extension


Time: 12:08 minutes



Liz Binversie: Greetings, I’m Liz Binversie, Agriculture Educator for Brown County UW-Extension and today we are going to begin this series on fall manure application by discussing nutrient management plans, how to comply with them, and why it’s important both for your farm and the environment. With me today on the panel are Carrie Laboski, Soil Fertility and Nutrient Management specialist for UW-Madison and UW-Extension, and George Koepp, Agriculture Agent for Columbia County UW-Extension. Carrie and George, what should farmers know about nutrient management plans?

George Koepp: Well, Liz, one of the first things that farmers need to do as they develop a nutrient management plan is to develop a soil conservation plan. This is primarily to address concentrated flow channels to prevent gulley erosion—making sure we don’t have any type of actual visible soil erosion that we can find out there. To do that, typically you will use crop rotations, residue management, and tillage systems to help keep that soil loss less than what we call “T”, or the amount of soil identified as tolerable soil loss. To do that, those items are all actually taken into consideration and embedded in this SnapPlus nutrient management computer program that was developed by UW-Madison and the Wisconsin Department of Ag, Trade, and Consumer Protection.

Carrie Laboski: Another aspect, Liz, as well is to use your nutrients efficiently. Especially in the current economic times with low crop prices, we really need to get the most bang for our buck when it comes to nutrients. Manure is an excellent nutrient source that we need to use the most wisely that we can do so and take credit for the amounts of nutrients we’re applying and not lose them. That will help reduce our fertilizer bill in the future.

George Koepp: To keep everything on the right direction, we want to minimize those nutrient losses, particularly to the atmosphere, to surface water, and to ground water. Our public partners are all concerned about that. We want to remind everybody that for every pound of soil that is lost, we lose nutrients and dollars are lost from the individual farm.

Carrie Laboski: And remember, for every pound of soil that’s lost, not only is it nutrients but it’s soil that can’t be replaced. It takes a long time to create soil, to get that good topsoil. There’s irreplaceable damage that is done as well. Now along with this, when we start thinking about nutrients and our nutrient management plans, a good way to think about it is the 4 R’s of nutrient stewardship. That’s a program that’s been put out by the fertilizer industry the past few years. It’s actually a great way to think about nutrient stewardship. The 4 R’s are the Right place, the Right time, the Right rate, and the Right source of nutrients. We’ll go into those in more detail. George and I have an extra plus one for these 4 R’s. We have a fifth and it’s called the Right data. Before we can even really get into the 4 R’s of about managing our nutrients well, we really need to think about having the right data to use to develop a nutrient management plan. Some key pieces that we need to have are good soil test data. Good data would be samples that have been collected within the last 4 years so they are relatively current, the fields have been sampled to a uniform depth, and ideally sampling at the same time of year – either in the fall or the spring is fine, but try to sample consistently within season. We use that soil test data to help determine the crop nutrient needs, the soil test phosphorous levels are used to determine the P index, and the total amount of phosphorus that may be applied to a field for manure. So those are key pieces of information. Some other right data that we need to have is our soil series and map unit information for our farms. Not all soils are the same across the state, and certainly not even within a single farm or even a field, so having quality information on our soil series and map units, and then the last piece that we will talk about today is manure analysis. We have good information about our manure, and getting our manure sample analysis is a great way to determine how much nutrients are actually available to us from that source.

George Koepp: The next Right we’re concerned about is the Right place. We want to put that manure in a location where it will stay and be ready for crop use the next cropping cycle that we’re in. So one of the things we want to do is to familiarize our self with a restriction map. And you should be able to see one here and know that there are an awful lot of markings on there. But very quickly, once you study it a little bit, you can identify where slopes are greater than 12%, or anything that is less than 12% we can apply some manure to. But some other areas we need to really, really be careful and stay away from. Follow those spreading restriction maps and setbacks, especially waterways. We don’t want to put manure where it’s likely to be washed off into surface water or down in the groundwater areas. We need to stay 200 feet from wells, sink holes, fractured bedrock, or tile inlets. We want to stay at least 300 feet from perennial streams, and 1,000 feet from lakes and ponds. One way it can help us a little bit, though, is to try to incorporate that manure within 72 hours, especially if you are within what we call a SWQMA or Soil and Water Quality Management Area.

Carrie Laboski: Now moving on to the Right time for nutrient application. Ideally, the best time to apply nutrients is right before the crops are going to use them, so that would typically mean sometime anywhere from May through early July. But we’ve got manure pits to empty, and we need to be doing that in the fall. So when we’re thinking about fall application manure, we need to consider things like soil moisture and rainfall, and there’s the manure advisory risk system that’s been developed by the Department of Agriculture, Trade, and Consumer Protection that can help you decide it’s too wet right now to make application safely without using that manure. The best place to apply manure is to lower moisture soils, but the rain we’ve been having recently, it might be hard to do that. Also applying before the ground is frozen would be key. And typically when we’re thinking about nitrogen management, 50 degree soil temperature has always been considered a rule of thumb. If you can wait to apply manure until the soil temps are less than 50 degrees, that really helps slow down the conversion of organic nitrogen into ammonium, and then ammonium forms of N into nitrate; and nitrate is the form that can be lost. So the cooler the soil is the better it is for retaining the nitrogen and keeping it for the crop next year rather than losing it this fall. And ideally we do want to try to avoid frozen and snow covered soils, although that is not always possible, but that’s where you get back to your spreading restrictions maps and thinking about where you should be applying now when you can get in the fields versus if you have to make applications to frozen or snow covered soils. For example, if you’re daily haul prioritizing which fields go to now versus which ones you can get at later. The other aspect of this, too, is the Right rate and knowing how much you can apply is really important. So, you need to think about what are the nutrients of your crop, that’s why we have soil test data to help us with that. Look at your nutrient source, if you have dairy manure, you have manure analysis, you know that if you apply a certain rate you’re going to have a certain amount of nutrients. So you really want to match the amount of nutrients applied with the manure to the crop need. You don’t want to exceed crop need. You can certainly go less than crop need and then come back with some fertilizer in the spring if necessary. So you do want to consider your soil test phosphorus level and the P index. Now the P index is calculated within the SnapPlus nutrient management program, and that will help determine the maximum rate of manure that can be applied from a phosphorus-based standpoint. And then you want to double check that that type of rate does not exceed the nitrogen need of the next year’s crop. Typically if you are limiting based on phosphorus needs, you’re not going to exceed the crop’s nitrogen need. And you certainly don’t want to over apply N so you want to balance both of those out.

George Koepp: That’s right Carrie, and finally we come to the Right source. So this is considering if we have solid manure, liquid manure, is it from a swine facility, a beef operation, a dairy farm, poultry manure, or even some farmers do apply commercial fertilizer, and those same rules will apply for commercial fertilizers as well. We really need to know and understand, as Carrie said, what are the nutrient needs of the crop we’re going to be growing and then try to match those up with the types of manure that are available to us. I know some farmers do not have a lot of choice; they have all dairy manure, so that’s what they are going to use. It is so important that they know what are the N, P, and K levels of the product they are putting out on the landscape so they can calculate how many gallons is the proper amount to be applied, and if it’s in a liquid form, how many tons of that solid type manure should be going out on the landscape. So we need to understand the Right source, what are our crop needs, and what source we have, and how can we match those up the best. So really, in summary, we have 3 major parts that we need to do for our nutrient management plan. The first part is to develop and follow that soil conservation plan, because as Carrie said earlier, if you lose your soil, you lose your crop growing potential.

Carrie Laboski: Yes, when you’re thinking about developing and following a nutrient management plan, consider the four R’s of nutrient stewardship plus one. It’s the Right rate, the Right source, the Right time, the Right place, and starting it all off with the Right data. You can visit the nutrient and pest management program’s website – that’s the UW Nutrient and Pest Management Program information like the nutrient management Fast Facts, manure application record book, and some other materials like that to help get you started.

George Koepp: And finally, manage those on-farm sources of nutrients using manure as an asset to improve the farm’s bottom line.

Liz Binversie: Thank you Carrie and George for being on the panel today. If you would like to reach Carrie and George, you can do so by email. Tune in next time as we discuss manure gas and road safety.