by Vanessa Renaud, Director, Ontario Federation of Agriculture
It might be hard to think about winter when we’re still in the middle of summer, but if you’re a livestock farmer, that’s exactly what is suggested. Specifically, it’s time now to think about how and when you’re going to get manure on the fields before the ground becomes frozen and snow covered.
That’s because winter application of manure, whether solid or liquid, is not a best management practice and should be avoided if possible.
In addition to farming in eastern Ontario, I’m also a crop consultant which means I work with farmers daily to help them grow the best crops and maintain healthy soils. Manure has great value as a natural source of nutrients, as well as building soil organic matter – good soil structure makes the ground more resilient to drought and flood stresses – and feeding the microorganisms that live underground.
How and when manure goes on the land, though, makes a big difference in the benefit you’re going to get from those nutrients and the impact they’ll have on the environment. When soil is frozen, manure can’t be worked into the ground the way it is during the warmer months. As well, water can’t enter the ground, so when it rains in the winter or warm temperatures cause snow to melt, it simply runs off and takes what’s spread on the frozen surface with it.
We don’t often associate winter with rain, but recent research from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has shown that winter rain and thaw events actually occur more often than we think. Studies have also found that Ontario’s phosphorous losses – nutrients from manure getting into water courses – happen mainly during fall and winter, and most often during and after major rain or melting events.
Here are some major reasons why farmers spreading in the winter is not a good idea:
Livestock manure is a valuable natural alternative to commercial fertilizer. When nutrients are washed away instead of being absorbed into the ground, it’s a bit like letting money go down the drain because they’re not providing any benefit to the crops. Those lost nutrients will result in lower crop yields, or they’ll have to be replaced, creating additional costs. Creating water quality problems
When nutrients run off into streams, rivers, and lakes at high levels, they have a negative impact on water quality and the broader environmental ecosystem. They contribute to increased algae growth, for example, which affects human, plant and animal life. A highly visible example of this that garners media attention every summer is the algae blooms that grow in the western basin of Lake Erie.
Building negative public perceptions
The algae bloom is one reason why there is increased attention focused on water quality in Ontario lakes. There are many contributors to this problem, but because activities involving manure are highly visible, farmers become an easy target for those looking to place blame. Contributing to soil compaction
Some farmers believe that spreading in the winter reduces the potential for soil compaction from heavy farm equipment because the frozen ground is better able to handle the impact of manure spreaders or liquid tankers. Unfortunately, that’s just a myth. Even though the soil’s top layers may be frozen, the ground underneath is not, and compaction will yield crop growth problems in future growing seasons. So, how can winter spreading be avoided?
Ontario farm organizations have been very proactive in raising awareness about winter spreading and most Ontario farmers know the risks and actively take steps to avoid them.
Often, those who do spread in the winter don’t have enough manure storage to make it to spring or weren’t able to empty their storages in the fall – because the weather didn’t cooperate to create proper spreading conditions, for example.
Still, it only takes one or two incidents to create problems for the entire industry, so here are some key points to think about as we head into fall harvest and prepare for winter:
Have a plan: know how much manure storage is available and be prepared with a back-up plan if spreading most of a farm’s manure in the fall isn’t possible, like temporary in-field storage for solid manure or renting unused storage space for liquid manure.
Storage: cover or expand existing on-farm manure storages. Keeping rain out of a liquid manure tank, for example, increases capacity without having to build additional storage.
Use crop rotation: add a crop like winter wheat, winter barley or winter canola, or cover crops to a rotation to provide extra manure spreading windows throughout the year. It will take the pressure off those busy spring and fall times and although it’s not a solution for this year, it can be put in place for the next growing season.
Follow the 4Rs: Put the right amount of nutrients in the right place at the right time and at the right rate.
For more information about responsible manure management, check out the Timing Matters initiative supported by provincial farm organizations and commodity groups.