Low pH Soils with Dr. Mark Liebig and Ryan Buetow

Soil Sense

In many cropping systems, the soil is becoming more and more acidic over time. This is happening to some soils quicker than others. A soil with a pH of 5, as an example, is 100 times more acidic than a neutral pH of 7. As these soils become more acidic, they can start to have problems with nutrient availability, nutrient cycling, and ultimately have an impact on yields. And unfortunately, they’re likely to get worse. We talk about what’s causing this acidification, some important sampling considerations, ways to fix these problems, and ways to slow the acidification from happening in the first place. Once again, this audio was taken from the DIRT Workshop this past fall. Go check out the youtube links and other podcasts to take advantage of this amazing resource on soil health!

Today you’ll hear from:

• Dr. Mark Liebig with the USDA ARS located in Mandan, North Dakota
  
• Ryan Buetow an Extension Cropping Systems Specialist at the NDSU Dickinson Research Extension Center.
  

“A lot of the soils that we have in the southwest part of North Dakota, they don't have the buffering capacity and soil acidification can get real really quick.” - Dr. Mark Liebig

He goes on to say that “we have a widespread global issue with respect to acidification” and that understanding the origin of these issues as well as mitigation efforts that can be made is critical. Sources of decreased pH include rainwater, the mineralization of organic matter, intensive land management with an abundance of applied nitrogen and the aggressive removal of residue on fields. All of these sources in combination make buffering the decreased pH more difficult for the soils to manage with the nitrogen application likely being the most significant. Ryan Buetow highlights the significance of sampling for pH at appropriate depths based on your risk factors. Acidic pH caused by nitrogen is most likely detected near the surface. A deeper sample may dilute the results giving a less representative sample.

“We've been trying a lot of different things. The best fix is really a liming. That's really what we want people to do with this issue.” -Ryan Buetow

Ryan suggests other “bandaid” type fixes like investigating different varieties of crops and adding strategic phosphorus to bind aluminum that becomes more readily available in a lower pH. Ultimately adjusting the overall pH with the use of lyme, although expensive, is the best way to cause widespread correction of the pH and avoid the potential metal toxicities and herbicide interactions associated with an acidic pH.

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Soil Sense Podcast is hosted by Tim Hammerich of the Future of Agriculture Podcast.