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When nutrient applications cost yield

Contemporary agronomy and plant nutrition management has been framed primarily around the Law of the Minimum: the nutrient with the most limited supply will determine the maximum possible crop yield. 

In practical application, we measure the nutrient concentrations that are present, either in soils or plants, and add what is missing or low. 

The Law of the Minimum paradigm is commonly misapplied with two gigantic gaps in thinking. 

This paradigm is often applied selectively to some nutrients. It may be applied to nitrogen, phosphorus, and potassium, but not to zinc, copper, manganese, cobalt, and molybdenum.

It is also common to apply this paradigm with no consideration for the opposing perspective, the Law of the Maximum. The law of the maximum states: the nutrients which are present in excess limit crops to the highest level of the nutrients that are antagonized by the excess.   

When we first started using sap analysis on a large scale, it quickly became apparent the law of the Maximum is often missed.

It is often the excess of the nutrients the grower applies, which causes deficiencies of other nutrients, that limits plant health and overall yield potential. 

Excessive nitrogen and potassium at the wrong stage of development cost yield on many farms, because of other nutrient deficiencies that are created by the excess.