Top 3 reasons to spread manure on snow


Depending on where you live, fields have likely been frozen now for quite some time. Maybe they’re even snow covered. Now is a great time to spread manure because that firm ground means you can travel and not create compaction, the storage is full, and, well, it’ll work its way into the soil later…right?

Well, two out of three reasons may be technically correct, but spreading manure on snow is, at best, a stop-gap measure, and, at worst, illegal (depending on your provincial regulations, see below).

Week in and week out, Peter Johnson, agronomist with RealAgriculture, fields questions and challenges on Wheat Pete’s Word on his “say no to manure on snow” message. While Pete has the patience of Job and answers the “not in my back yard” questions every time, even our user experience lead and resident gardener Rhett Soveran is pulling his hair out wondering why farmers just don’t seem to get the memo. What IS the deal with farmers’ reluctance to accept that winter and spreading don’t mix?

I decided to ask Pete to recap your neighbour’s most common reasons for winter spreading, and I’ve compiled them here in a handy Top 3 list format for easy consumption. Here we go!

I won’t cause compaction: “If the ground is frozen, I’m not doing any damage to the soil.” This is true for compaction, but not at all true for the environment, soil fertility, soil biology, soil health, AND total value of the nutrients in manure. So, yes, technically you’re not compacting the soil, but you’re shooting yourself in the foot other ways. More on that in a moment.

I don’t have enough storage: This is a solvable and manageable problem. Pete used some very colourful language when asked about this one but it comes down to this — if you have livestock, you need a nutrient management plan including AMPLE manure storage. Either expand the storage or shrink the herd/flock. This is a factor of being a professional livestock farmer. What’s more, there are regulations for such things. Be sure to contact your provincial agriculture extension to be fully aware of the rules.

I have flat ground; that manure isn’t going to go anywhere. There’s a saying that water finds its level. And it always runs downhill. Are you trying to tell us that no water ever leaves your farm? That the manure doesn’t move ANYWHERE? All water — over the surface during a winter melt or through the soil profile — will move and eventually join a waterway. Nutrients and solids in manure spread on frozen ground are more likely to end up in water vs. manure spread on thawed ground.

We know that dissolved phosphorus (you can’t see it in meltwater) can cause nutrient loading in waterways, lakes, and rivers. Are algae blooms in the Great Lakes or Lake Winnipeg all farmers’ fault? Of course not, but agriculture land use was and is a contributing factor. Keep the P where it belongs, and don’t spread on snow.

Pete further explains that even if the water doesn’t leave your farm, it pools in the low spots and the “micro” low spots. You see evidence of it in the wheat crop: a multi-coloured field with dark green patches with too much nitrogen, and, just 12 inches away, “it’s yellow as ye olde duck’s foot” and nitrogen starved. If you’ve seen this and wondered what happened, wonder no more.

Which brings us around to the question: Why are you spreading manure, anyway? Yes, it’s a byproduct of livestock production, but we also know that manure is brown gold for soil building and crop production. Fields with a history of manure applications are high producers. Manure helps build soil biology and organic matter. Manure replaces valuable nutrients. Manure is a fertilizer. That’s the entire point. Spreading on snow decreases the chances that any of that super valuable fertilizer ends up where you want it — on your fields and in your soil.

Bonus reason: We’ve always done it this way: Gramps did it. Dad did it. Why is it so wrong now? Because we know better. Because we have to be better. The generations before did great things in their day, but not everything they did was the right thing to do. History is not a good enough reason.

Winter spreading is a “contingency plan” in Ontario, when you can’t empty out because the fall is too wet and the storage is overflowing. (See the full OMAFRA fact sheet on winter spreading here). 240 day storage is the minimum regulation for those requiring a nutrient management plan, but recognize the likelihood of that not being enough. 400 days is probably closer to optimal, Pete says. Yes, spring spreading ahead of corn can be challenging, and we know that needing November to spread doesn’t always work out. Plan ahead and be part of the solution.

Provincial regulation and resource links: 

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