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Tuesday, January 28, 2014

Crop Root Growth

When we talk about soil health, we are really talking about having a healthy soil soil that maximizes root growth and nutrient release.  At the National No-Till Conference, Dr. Joel Gruver of Western Illinois University made what I thought was the best presentation of the conference.  Maybe I should have written this as my first post conference blog.  Many thanks to Dr. Gruver for sharing his presentation with me so that I don't miss any of the highlights.  His talk was entitled 'Maximizing Crop Root Growth in No-till Systems."  It should have been subtitled "Crop Root Physiology 101."

Dr. Gruver's lead question was, "crop yields have improve three times over a lifetime, but have soils improved?"  Another question to ask is "why are yields so variable on a field basis?"  Gruver says "Root Performance = Genetics X Environment"  Evidence of the importance of roots is in GMO corn.  The two most important traits marketed are weed control and root enhancement.  The root enhancement comes because the Bt corn resists corn rootworms and make for a stronger root system.

One of the books on Gruver's reading list was "Plant Root - the Hidden Half"  Gruver talked about  root cortical aerenchyma, a plant's response to stress, and how it can be used to get the plant to respond positively to stress.  Gruver predicts that we will be hearing more about biological amendments in the future.  He says the "big guys" like BASF, Syngenta, and Monsanto have gotten into the world of biological enhancements.  In the past, the value of biologicals has often been in question because of sketchy research.  These bigger companies will have the money to do serious research.  Gruver predicts that these products are most likely to show a return on investment under adverse conditions.  A current and commonly used product is Votivo, used in combination with Poncho as a seed treatment.  Legume inoculants are probably the most familiar biological enhancements.  Gruver says that sales reps should be able to clearly explain how their products work.  In the past, this type of explanation has been vague to non-existent. 

Gruver says we should dig into the soil and look at our crop roots to see that they are healthy.  Healthy roots are white, proliferate in all directions, extend into the subsoil, and have minimal deformities.  Use and air hose and a shop vac to clean the soil away from the roots.

Gruver says that Chronic Root Malfunction is all too common in modern agriculture.  Chemical imbalances can be part of the problem, for example, low pH can cause aluminum toxicity.  He pointed out that one of the reasons that Gypsum is becoming popular is that it can help overcome soil structure problems and high sodium problems in some soils.

In row fertilizers are marketed as crop-safe, but under dry conditions especially, they can become toxic.  Gruver shared a South Dakota State University calculator that can be used to  determine the maximum rate for in row fertilizer.

Gruver discussed how soil nutrients, soil water, soil temperature, and compaction all affect root growth.

Gruver says mycorrhizae are the internet of the soil.  Roots only take up 1% of the soil, but mycorrhizae add to the effectiveness of roots because they take up 10% of the soil.  His 4 main strategies for enhancing root biology are:
  1. Conservation
  2. Augmentation (inoculant)
  3. Activation
  4. Suppression
  Gruver discussed how cover crops can suppress diseases and help with weed control.  He also presented information cover crops increasing root density.

Gruver said that a system to look at is the one that Dean Glenney  is using to grow high yielding corn and soybeans in Canada.  Glenney's Fencerow system changes the biology in the soil and in the plants.

Thanks again to Dr. Gruver for sharing his information with me so that I can share it with my readers.  This is a summary of what he told us. This is likely my last blog from the National No-Till Conference.  Next year it will be in Cincinnati.  Registration for next year's conference is currently deeply discounted.  

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