Symbiotic Relationships in Ecology with Don Huber

In this episode, I had the pleasure of interviewing Dr. Don Huber, a leading plant pathologist and Professor Emeritus at Purdue University. We discuss how to manage soil-borne diseases by managing crop rotations, and the management needed to grow 500 hundred bushels corn. Don shared intriguing observations on how soil-borne disease pathogen populations remain present in the soil constantly and are actually 'beneficial' saprophytic fungi until the right environment is present. Root diseases are a result of the soil environment, not a result of the presence or absence of the organism.

Support For This Show & Helping You Grow

This show is brought to you by AEA, leaders in regenerative agriculture since 2006.

If you are a large-scale grower looking to increase crop revenue and quality, email hello@advancingecoag.com or call 800-495-6603 extension 344 to be connected with a dedicated AEA crop consultant.

Related Resources

• Mineral Nutrition and Plant Disease by Lawrence E. Datnoff (Author, Editor), Wade H. Elmer (Editor), Don M. Huber (Editor)
• Marschner's Mineral Nutrition of Higher Plants by Horst Marschner (Author)

Episode 4 - Dun Huber - Highlights

2:40 - What are Don's most memorable moments leading him to where he is?

• Don has fun wherever he is!

3:10 - What has puzzled Don in his research work?

• Studying soil ecology is looking at a black box. Need to slowly build a picture of everything involved.

4:10 - What is something that has surprised Don?

• How seemingly contradictory things all work together, such as a lot of nutrient relationships
• Secondary functions of things like manganese and iron start to come into play
• What are the ecological niches that make the system work?

6:30 - Challenge of manganese availability. What is contributing to that?

• It's a dynamic relationship with soil and fungi.
• Need organisms and nutrients to increase uptake
• Need the bacteria that are responsible for the valiant state - oxidizing groups and reducing groups
• Manganese can be there, but not available for uptake

11:10 - Pathogens dependant on manganese oxidation. Are they directly dependent, or are they producing a manganese-deficient plant?

• Both can be correct. They don't necessarily need the oxidation.
• Enzyme isn't going to work for you without a cofactor

13:50 - How do populations change when you have a crop infection?

• The plant is providing nutrients and resources for the pathogen
• Soil inhabitant vs soil colonizer
• A soil colonizer is an organism that can be provided its nutrient base from a host
• Infection isn't the result of the presence of the pathogen, but the level of plant health and microbial ecology in the rhizosphere

20:20 - What are the tools the growers have available to manage soil ecology most effectively and to develop a disease suppressant soil profile.

• Crop rotation - each crop influences a certain group of organisms in the soil
• Cover cropping
• Time of tillage
• Farming is really managing ecology

28:30 - Is it also possible to use these tools to manage and suppress soil-borne pathogens?

• Definitely!

31:20 - What are some useful crops or cover crops that have a strong disease suppressive effect?

• Depends on disease and overall soil biology
• Perhaps the best crop: Oats!

36:50 - What are the key characteristics shared by disease suppressing crops?

• Boils down to nutrition - may be indirect or direct

39:10 - Can fall tillage application create a rebalancing effect of both reducing organisms as well as oxidizing organisms?.

• Yes! Doesn't have to be every year
• Long term no-tillage can reduce the efficiency of ecology

41:20 - What are the impacts of nitrogen on developing disease suppressive soils?

• Most soil organisms are hungry for 2 things: nitrogen and carbon
• Changes can cause massive stimulation

44:30 - What is the impact of ammonium on an ecosystem with reduced nitrogen

• Tremendous reduction of disease
• Reducing environment creates an increase of manganese availability

46:30: What is the impact of carbon-nitrogen ratio on disease suppressive soils as well as yield?

• Depends on the carbon source
• It's not the carbon to nitrogen ratio, it's the form of nitrogen involved
• Ratio works if working with the same nutrient source

48:30 - Quality/Quantity of photosynthesis - How can we increase quantity of photosynthesis and quantity of root exudates in soil profile.

• Manganese, manganese, iron, sulfur, etc. are essential for photosynthesis
• Mineral nutrient deficiency will reduce overall efficiency.

54:30 - We are not tapping into efficiency of plants by limiting carbon dioxide

55:10 - Increase in photosynthesis producing increased biomass

55:30 - What is the potential for plants to increase their volume of photosynthesis?

• The potential is 100%
• 5-10x depending on what the plant it, starting point, etc.

1:00:30 - What kind of yields did Don achieve during his yield trials? What plant populations were growers using?

• 350+ bushel

1:07:10 - What happened from then, to today when growers are struggling to grow 250 bushel? Why were these not adopted on a broader scale?

• Focus moved to other areas when there was "too much production"
• Requires a long term commitment
• Private company interest is the bottom line
• We forget it's an ecology that needs to be managed

1:11:30 - What is something Don believes to be true about modern agriculture that others do not believe to be true?

• Have to think about entire systems, and not focus on a single piece
• You have to make a few mistakes in order to get there

1:14:00 - What does Don see as the biggest opportunity in agriculture today?

• Reinventing the wheel!
• Getting back to nutrient density
• Eliminating pesticides, especially glyphosate
• Agriculture is the basic infrastructure of society. Recognizing the stewardship we have to the soil

1:18:10 - What are some books or resources Don would recommend?

• Mineral Nutrition and Plant Disease by Lawrence E. Datnoff (Author, Editor), Wade H. Elmer (Editor), Don M. Huber (Editor)
• Marschner's Mineral Nutrition of Higher Plants by Horst Marschner (Author)
• Systems looking at nutrient density

1:22:30 - What is a question Don wishes John had asked him?

• Glyphosate's impact on soil ecology
• Don is excited to see cover crops being used
• Maintaining balance within soil environment
• Supporting the crop with nitrogen

Feedback & Booking

Please send your feedback, requests for topics or guests, or booking request have a Podcast episode recorded LIVE at your event -- to production@regenerativeagriculturepodcast.com. You can email John directly at John@regenerativeagriculturepodcast.com.

Sign Up For Special Updates

To be alerted via email when new episodes are released, and get special updates about John speaking, teaching, and podcast LIVE recordings, be sure to sign up for our email list.