The stories our soils tell

Unless you’re someone who has a soil pit dug on the farm, it’s rare to see more than the top few inches of soil. But what exists below has a significant impact on what happens above, and the better we understand the characteristics of our soil, the better we can manage its potential and limitations.

Marla Riekman, Manitoba Agriculture soil management specialist, (@MBsoilsleuth on Twitter), hosted a six-foot-deep soil pit at this summer’s Crops-a-palooza event at Carberry, Man., showcasing six different crops’ rooting structures and showing off the layers of soil that feed a crop all growing season long.

Despite total rainfall only around 77 per cent of normal for the region this year, crops were looking good due to the soil — a class one clay loam from the Ramada series.

In this particular soil pit, farmers could view the rooting structures and depth of corn, hemp, sunflowers, soybeans, oats, and canola, and many were surprised by just how deep the roots of each of these crop types would go, Riekman says. (story continues below)

“When you can actually see that much space, and see the variability in the soil, and see the variability in the crop roots and how deep they are, people are pretty excited to be able to visualize it,” adding it’s not something farmers often get a chance to see.

Visualizing soil structure, depth, and rooting patterns are very important, as the horizons and make-up of soil tell the history of how that soil was formed. That history informs how a soil will act under different conditions, what its water holding capacity might be, and even which nutrients may need to be applied in higher rates, various forms, or closer to the crop, depending on pH and soil structure.

Farmers who toured the soil pit had many questions regarding dealing with salinity, compaction causes and risks, and structural limitations of soil. In a dry cycle, salinity can rear its ugly head, and Riekman says that some farmers are using weeds or forage in saline areas to draw down the water table — a great fix, so long as the weeds remain vegetative and are not allowed to set seed, she says.

P.S. We’ve learned that sheep DO eat kochia, and it’s even nutritious! 

 

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