Spread More Lime, Work Fewer Acres


One of the first articles I ever wrote for the popular ag press was titled “Lime may be your tractor’s best friend.” The year was 1977, and I was employed as an agronomy Cooperative Extension agent. The idea behind that title was that if crop yields drop because soil pH is too low, more land must be worked in order for the farmer to harvest the necessary feed tonnage required by their cattle herd.

Of the three major crop nutrients (nitrogen, phosphorus and potassium, or N, P and K), I placed most of my emphasis on N. This is because with commercial fertilizer, N and P supplies are closely related. N can be applied to land separately from P in the commercial (non-organic) fertilizer world. In that same world, P cannot be applied apart from N: P must be applied as mono-ammonium phosphate, or diammonium phosphate – period. Some fertilizer manufacture review comes in handy here. Conventional (non-organic) phosphate fertilizer production starts with mined rock phosphate ore being treated with sulfuric acid. This chemical reaction yields phosphoric acid and waste slag. The phosphoric acid is treated with ammonia, a reaction which yields mono-ammonium phosphate (MAP); when MAP is treated with more ammonia, the result is di-ammonium phosphate (DAP). The fertilizer analysis of MAP is 11-52-0 (N-P-K); the analysis for DAP is 18-46-0. Since ammonia is made from natural gas (CH4), along with carbon dioxide, atmospheric N and water, CH4 costs greatly influence costs of all forms of commercial N as well as P fertilizers.

Potash (K), the third macro-nutrient, is somewhat independent, politically, of N and P. But in biology, N, P and K are very dependent on each other, all very critical for any life form. But, again, politically P and K are in their own kingdoms, largely because their ores are mined in quite different geographic locations. Here’s why potash, which is actually only 83% elemental K, was recently center stage, drawing both political and economic spotlights. Even before all the human tragedy engulfing Ukraine started, Belarus, another former Soviet Union member, began diverting potash supplies from Lithuania to Russia. Belarus started reallocating potash shipments from Lithuania’s ports to Russian ports, after Vilnius, Lithuania’s capital, decided to halt the use of its railway for Belarus exports of this critical plant food. Lithuania stopped railway transport of Belarusian potash on Feb. 1. A Lithuanian diplomat said that Minsk, Belarus’s capital, which is under U.S. and European sanctions, could not use Lithuania to export the crop nutrient, which is a primary foreign cash cow for Belarus. Washington had imposed sanctions on Belarus in 2021 and then black-listed its export arm, Belarus Potash Company (BPC), as part of the West’s punitive measures against that nation’s President Alexander Lukashenko over his crackdown on political opponents.

This geo-political scenario is anything but boring. Fortunately, there are huge potash resources in North America. In Saskatchewan, K+S Potash is part of the K+S Group, a German-based company that has been mining and processing potash and salt for over 125 years. With all the military and political confusion in eastern Europe, we expect continued upward price pressure on potash, despite the mineable abundance of this fertilizer ingredient enjoyed by our neighbor to the north. Perhaps more than any other commodities, besides energy, fertilizer ingredients are very susceptible to supply/demand tensions impacting the global marketplace. Let’s illustrate this fact: American Farm Bureau data show that in 1961 U.S. farmers consumed 25% of the world’s fertilizer. And in 2018, the last year they cite data for, American farmers only consumed 10% of the planet’s fertilizer manufacture. This doesn’t mean that crop growers in the U.S. used less fertilizer; it means that growers elsewhere on Earth significantly increased tonnages of N-P-K fertilizers they use.

With all the global uncertainty surrounding the fertilizer aspects of growing crops, let me restress the need for soil testing as the cornerstone of successful crop programs. Having the knowledge enabling growers to resolve pH problems directly improves the efficiency of herbicides and fertilizers. This in turn usually let farmers lower fertilizer applications. Where most herbicide and fertilizer ingredient costs have doubled, and even tripled, in the last two years, ag lime cost increases remain in single digit percentages.

All the other crop inputs, like seed and ag chemicals, join commercial fertilizer ingredients in their meteoric price increases. Experts predict little price relief for most of the 2022 growing season. The biggest 10 commercial fertilizer ingredients have increased by more than 125% on average in the last two years. That list includes urea/ammonium nitrate, urea, ammonium nitrate, ammonium sulfate, anhydrous ammonia, diammonium phosphate, muriate of potash, sulfate of potash and various forms of sulfur. The good news is that ag lime, this cheap input, can be used to help soils utilize these expensive plant foods more efficiently so that fertilizer rates can be reduced. The flip side to this coin is that with pH issues resolved, and fertilizer rates held constant, crop yields increase, enabling the grower to let go of some acreage, usually rented and farther away fields.

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