Written by Matt Ververs, North Simcoe SCIA
North Simcoe was the host of the third in the series of Crop Walks presented by the Georgian Region Soil and Crop Improvement Association.
This crop walk featured soil root pits dug in a corn field with heavily compacted soil. Each pit was dug in a different management zone for this year’s crop. In the pits were two OMAFRA staff, Soil Scientist Dan Saurette, Land Resource Specialist; and Alex Barrie, Soil Management Engineer. The two experts provided an analysis of the root systems and soil structures seen in the pits.
The event featured Bev Agar, President of North Simcoe SCIA, Andy Van Niekerk, Georgian SCIA provincial director, and Matt Ververs, who masterminded this plot and event. The was site located in Elmvale. Six tillage practices were done pre planting, to compare how they would stack up against each other beneath the heavily compacted soil. Observation from Soil Scientist Dan indicated that this area was a lake bottom, and that it would have been beneath water thousands of years ago. “The clay deposits that show bright orange prove this was a lake bottom- and we know this type of land runs from here (in North Simcoe County) right down to Prince Edward County (in eastern Ontario). Engineer Alex pointed out that the top four inches of this soil profile was “very compacted to the point that it was made into a patio slab right across the field,” he said.
The first pit was planted green into cereal rye that was terminated after planting. Although in the stand, population was not ideal, it was impressive beneath the soil to see what the natural root “tillage” had accomplished. It was in the end, the most even, and had the best soil tilth of all the sites. Seed depth at planting did not make it to the moisture which affected this plot, and the no till plot.
No till was the next plot. This plot had a high worm presence with many evident “worm holes” and worm middens “which is what I like to see in a field”, commented Andy. Engineer Alex commented that “the depth of the (corn) root was at least 60 cm into the soil as it was searching for moisture.” He also added that “you want to see your roots holding on and traveling throughout the soil, which means it can better draw nutrients into the plant. The more roots means the more location available to do the business of growing.” He said the negative about this site however was that it was easy to pull out the plant. It could have used more deep rooted main roots, but they could not get down due to compaction and no tillage.
The third root pit saw a fall pass of a deep ripper set at 18 inches and on 30 inch centers. This pass did prove to fracture the soil at depth, but still left very large soil aggregates. This helped for root penetration between the shanks. Vertical root mass was improved but with the high HP and extra fuel burned, this practice is not ideal for entire fields, and may be better suited for specific issue areas in a field. Andy suggested using a stand of alfalfa for 3-4 years and let the natural tap root do the tillage for you.
Plot four, featured a fall pass with a shank strip till unit that applied fertilizer in the fall beneath where the corn seed was to be planted in the spring. It saw a “spring freshen” pass with vertical blades to soften the seed bed and warm/dry the strip before planting. A corn stalk here was easy to pull out, and showed a good root system. Soil Scientist Dan commented, “The aggregates here are smaller and more manageable”. The idea behind the lower fertilizer band is to draw the roots down to where the water is so if we suffer from a summer drought, the roots have an abundance of lower roots and food source to keep it going.
Plot five was a spring strip till, four blades instead of a shank. Strip freshen is good for speed and disturbs the least amount of soil while preparing the seed bed and warming the soil. Here, when a corn stalk was pulled out, there was more of a root ball, but it was a shallow root system. “We can see there are shelves in this soil, like steps. The roots here gave up past the first shelf and started to travel sideways- but the corn looks like it did well,” observed Engineer Alex.
The last plot was a single spring pass of a vertical till disk, running at approximately 3 inches. Andy commented, “I’m not a fan of this because it runs the risk of the residue pinching the seed, because all that residue is in that top 2.5 inch depth.” In the pit, the risk was realized. It was “found that roots did not even get down past last year’s crop roots. The chunks here are so thick and hard we cannot even break them up,” Engineer Alex concluded. Realistically this is a great tool in the tool box, but it is not a great idea to use on compacted ground as the compaction layer was very evident.
To watch the complete North Simcoe Virtual Walk, go to https://www.youtube.com/watch?v=I8FKPt0-Yuk