Yes, compaction happens. You know that, I know that. But we in Canada are ever so fortunate because while compaction does happen, Mother Nature, at her cruelest -30 degree C self, actually helps us battle it with our wicked Prairie freeze-thaw cycle. Right? Well, yes, but a more resounding no, actually.
Marla Riekman, land management specialist with Manitoba Agriculture, Food and Rural Development, wants to set the record straight on two things: freeze-thaw cycles don’t do a lot to fight compaction in our soils and tillage as a means of dealing with compaction is only sometimes the solution (or part of it). Say what?
Mother Nature DOES help fight compaction, but it’s actually the wet/dry cycles and resulting swell/shrink action of our prairie soils that have the greatest impact on fighting compaction, Reikman says. That’s because of two things: while the top two to six inches of soil may freeze and thaw a few times in a year, the entire root zone (and deeper) may freeze and thaw only once a year. Why does that matter? Because of point two: compaction doesn’t just mean a plow pan six-inches deep from a cultivator smear, it actually happens as far down as two to three feet.
And here’s the second lesson: because compaction happens two or three feet down in the soil profile, a tillage implement is rarely going to alleviate yield loss from compaction. There are those that claim vertical tillage, designed to “shatter” compaction deep in the soil profile, will fix this, but Riekman counters that a tillage implement breaks up compaction in the range it runs in only. The science doesn’t show any measurable impact beneath that range. So, what then should farmers be doing about compaction?
In the interview below, Riekman explains that preventing compaction is the first step, and that some farmers may be surprised to learn that it’s actually when fields are moist (not saturated) when the most damaging compaction happens. What’s more, deep ripping has been show to offer resulting yield payback in only 50% of cases according to some research (so, yes, tillage does sometimes help). To that end, Reikman offers her tips on what fields or field areas make the best deep ripping candidates in the interview below.