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user picture Paul Carter

How deep are corn roots now?

  • 4 votes

As we have discussed in another post, a very important factor in how well our crops will respond to this dry weather is root growth and capability to extract soil water.

The table below shows recent average values determined by Iowa State University researchers for a range of Iowa soils. Click on the visual for a larger view.

On average corn roots are 20 to 30 inches deep for much corn that is now at V6 to V10 stages. This will vary with soil type, soil structure, and what we used to call "soil tilth". 

Maybe someday we will have visual sensors to observe daily root growth during the season like we can easily do for the above ground plant. For now, a shovel is the tool we use! It's a good idea to use that tool in a few areas of fields for visual root observations.

Does anyone have some observations of 2021 root growth to share?

 

 

 

 

 

  • Corn
  • Soil & Water Management

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This is really cool info, thanks Paul! I hope to get out and dig some plants for root development and see if we can't get some of these deep roots, they always break off for me. 

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It would be cool to plot the variability of the 'Root Depth During Vegetative Growth' chart on a graph along with variation in management practices. I would bet that fields that have been in no till and cover crops for three years or longer will have deeper root growth than conventional tillage fields without cover crops which may suffer from compaction. It would also be interesting to show correlations (or lack thereof) with water tables/precipitation and subsurface drainage. Thanks for the informative post, Paul!  

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Mary Pat:

Digging and finding deep roots is tough. That's why research in this area is so challenging.

Here is a nice, short piece with photos by one of my former agronomist colleagues on using a spade to evaluate seedling roots.

http://https://www.pioneer.com/us/agronomy/diagnose-emergence-issues-square-bottom-spade.html

 

 

 

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Later in this season, the roots in the top foot can be evaluated similar to the research tool called "shovelomics" described here.

See photo for examples of some features to evaluate.

https://plantscience.psu.edu/research/labs/roots/methods/field/shovelomics/shovelomics

 

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To measure soil impedance to root growth (see article posted today on that), a soil compaction tester or penetrometer is probably a better way to go than a shovel. But soil needs to be at field capacity for reliable measurements, so now is not the best time for this! See more on soil compaction testers here.

https://extension.psu.edu/time-to-evaluate-soil-compaction-with-a-soil-compaction-tester

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Sean:

To your comment on measuring and observing the influence of management practices such as no till and cover crops on root growth and depth....yes! Please see my post today on how important this could be based on a theory relating the importance of  "unimpeded" corn root growth and corn yield.  We need better tools to evaluate roots.

 

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