Soil Acidification: An Awaking Giant

Joel Huesby has taken the initiative to be the first contributor to our blog at HolisticManagement.Guide. Joel has been and continues to be a leader in most everything he undertakes. He was one of the first grass finished producers, at scale. He was one of the first with a mobile slaughterhouse. Being on the cutting edge, Joel has taken many risks and made mistakes. Lucky for us, his humility allows him to share not only what he has learned, but he provides information on what we need to make sound decisions.

Joel farms on the Touchet River, near Walla Walla, Washington, amid an area in the Pacific Northwest where an estimated 40% of the rich Palouse soils have been lost to erosion since farming began in the late 1800’s. Joel points at that we have been poisoning what soil remains. In this article, he lays out the cost Nitrogen fertilizer has brought with soil acidification and how we can reverse this process. Incidentally, reversing soil acidification requires the same treatment as reversing climate change; getting animals and human creativity to the soil surface.

Please enjoy Joel’s contribution on soil acidification. Comment and Follow him!


The December 12th headline article, “Region’s farmers seek answer for soil acidification” describes what may well be the most far-reaching threat to conventional crop production -- soil acidification. The repeated application of relatively inexpensive nitrogen fertilizers over the past 70 years or so has indeed increased crop productivity, but it has also come at a great hidden cost.

The threat of soil acidity is like an unseen sleeping giant who is only now being awakened. Soon enough, it will be very difficult, if not impossible, to undo what was done. Even moderate soil acidification is hideous because it prevents crop roots from growing properly and taking up nutrients. The very practice that gave abundance now takes life away. Few things in nature come free. It turns out that particularly ammonic-based nitrogen fertilizers are both plant food and soil poison. You wouldn’t want to take a whiff, but the nose knows. If soil acidification is not abated or reversed, food insecurity—on a local as well as global scale will surely follow – and like the giant, it’s already awaking here close to home. This should get your attention.

To understand, let’s dig deeper into this battle of the charges within the soil. We need to know that acidity is measured in parts Hydrogen, or pH, using a logarithmic scale from 0 to 14 -- where below 7 is acidic and above 7 is alkaline. Chemically, nitrogen fertilizers, particularly the ammonic and urea based forms, acidify the soil by releasing hydrogen or (+) charges. Negative charges from a base such as Lime (Calcium Carbonate) combine with the positive charges and neutralize acidification. Unfortunately, these forms of N also happen to be the most affordable.

Soils in the foot hills of the Blue Mountains of Walla Walla and Columbia counties, the Palouse, and the Idaho panhandle regions indicate that acidity is widespread and becoming more severe, much with a soil pH well below 6. Peas and lintels get into trouble below 5.6 and wheat below 5.2. But some pH samples are in the mid 4’s -- nearly 1,000 times more acidic. Our remarkable soils have had the ability to buffer, that is, to mask or hide the harmful effects for a time. Like the giant, his rumblings went largely unnoticed and then… there he is.

Amendment or correction won’t be easy. In the soil on a chemical level Lime must be mixed with several feet of top soil, not just applied to the surface in order for the reaction to occur.

Here’s the reaction: CaCO3 + 2H+ (from fertilizers) → Ca2+ + CO2 + H2O (or Calcium Carbonate plus two Hydrogens results in Calcium plus Carbon Dioxide plus Water).

Lime is relatively heavy (molecular weight 100, for two negative charges) compared with Ammonia NH4 (molecular weight 18, for one positive charge). In other words, it takes almost three times as much lime by weight to neutralize the acidic effects of ammonia.

Applications of acidifying Nitrogen fertilizers have been occurring—and accumulating—since the 1940’s. For example, at a modest application rate of say 50 pounds Nitrogen fertilizer per acre for the past 75 years works out to 3,750 pounds. To restore the soil to its original pH then would require about 10,000 pounds of lime on each and every acre!

To gain a sense of scope, in Washington State there are about 15 million acres under agricultural production on 35,000 farms whose average size is 434 acres (Source: USDA: National Agriculture Statistics Service). The lime needed just in Washington State would be over 150 billion pounds or 75 million tons or 6,818 train loads of lime!

Who is able to purchase this much? Economically, it won’t happen.

What quarry will it come from? And how will it be distributed? Logistically, it can’t happen.

While these claims are generalized, and since soils can buffer (that is, mask the effects) we won’t need 100% restoration to get productive results. Still, this is just Washington State, not the United States -- or the world for that matter. It’s a big problem. This colossal sleeping giant must never be fully awakened. The thing is, farming and the environment go together. Chemistry and biology. The laws of nature are known and predictable; break them and suffer, obey them and prosper.

So, what to do?

Isn’t it interesting and wonderful that the prevention of soil acidity has already been created? It’s up to us to just put it back together again. Crops and livestock/poultry are complimentary to each other. It turns out that the waste of the one is the ideal food of the other and visa versa. It takes a lot of fuel, equipment, and labor to haul the crop from the soil to the livestock and then to haul the waste from the livestock back to the soil. We should keep these as close together as is optimal. Generally, I believe they’re too far apart these days.

Did you know that there is over 34,000 tons of Nitrogen above each and every acre the world over?! (Do the math… 14.7 pounds of air at sea level; 78% N in the air; 144 sq inches in a sq foot; 43,560 sq feet in one acre; 2,000 pounds in a ton!) But this free and healthy source is unavailable to the chemically dependent soil on most commercial farms.

Organic Nitrogen from legumes (pod-forming crops), livestock (“waste”), and “free-living” bacteria (soil food web) within a biodynamic humus under rotation with grains and vegetable crops mean that we will never acidify the soil on our organic farms as they remain productive into perpetuity. Since we are really stewards taking care of that which is not our own, these resources can be passed on to our children in better condition than when we first began.

As inspired and informed customers, you can choose to purchase foods grown by farmers that incorporate these practices. Seemingly small acts at your grocer or favorite restaurant can and do add up. Nothing happens on the organic farm without the financial incentive provided by our urban partners in regenerative agri—culture.

An interesting book on this topic which I encourage you to read is “Dirt: The erosion of Civilizations”, by David R. Montgomery which traces the role of soil use and abuse down through history.

Together, we can create a new history that future generations will look back on, admire our resolve, and remark, “They understood, they got it right!”


Joel Huesby4 Comments