To fall till – or not
By Alberta Agriculture and Forestry
Sept. 8, 2015 - The decision of whether or not to till in the fall is not one to be made lightly.
"Zero tillage has favoured some weeds while others are easily controlled," says Harry Brook, crop specialist, Alberta Ag-Info Centre, Stettler. "Fall tillage can be a useful tool in dealing with some of these weeds, but there can be repercussions."
One reason for fall tillage is to get some topsoil on the surface so it warms quickly in the spring and the crops can get off to a quick start.
"However, if you have a light textured soil that is easily eroded by wind or water you might think twice before bringing soil to the surface. You try to minimize the amount of stubble that's buried, and a cultivator will bury less than a disc will. There are also vertical tillage machine now that brings soil up but doesn't bury a lot of topsoil. You're trying to find that balance between having enough soil on the surface to warm the soil in the spring, and minimize the risk of erosion problems."
He says a dry year like this can influence the decision on whether to fall till.
"If we have light crops and not a lot of residue, you might not need to till. Every time you till, you are adding oxygen to the soil which speeds up organic matter breakdown. And it releases more nitrogen for the next year. However, the downside is that you might be mining your soil's nutrients."
He says it's important to be very clear why you are fall tilling, if you choose to do so.
"If it's to warm up the soil, perhaps look at other alternatives. If you've got really good chaff and straw spreading you might not have to till, but if you have serious weed problems that are not responding to herbicide, some limited tillage might be useful."
"The decision on whether or not to till in the fall can affect spring fertilizer requirements, emergence, soil warming and when you can actually seed," adds Brook. "The ramifications of cultivating can extend well into the next year."
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