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Liebig’s Barrel Demonstration: Ag Science from a Fountain

Using a big barrel and some water, we’ve helped demonstrate an almost 200-year-old principle of agricultural science. Introducing Liebig’s barrel demonstration from the AgroLiquid IQhub.

(You can view this agricultural exhibit on our custom products page.)

Liebig's Barrel Post PromoIt’s the Law.

The six nutrients of Nitrogen, Phosphorus, Potassium, Magnesium, Sulfur, and Calcium are essential to the growth of any plant. If these nutrients are not present in the soil, then the farmer must add the appropriate fertilizers. These fertilizers will give the crops their needed nutrients.

Oftentimes, the health of a plant depends on whether or not the farmer has provided the correct fertilizers in the right amount. In fact, even if only one of the needed nutrients is lacking, the plant will continue to suffer. The farmer must meet all of the plant’s nutrient needs.

In the 1820s, Carl Sprengel came up with a principle that helped explain a plant’s need for the correct amount of every nutrient. Later termed the “Law of the Minimum,” this very principle was later promoted by Justus von Liebig. It’s now primarily connected to his name.

According to this “Law of the Minimum” developed by Sprengel and used by von Liebig, the scarcest resource available to a plant is the one that will determine its rate of growth. In other words, a balanced approach to nutrients is the one that will most benefit a crop. That’s why a farmer can’t be scarce in one nutrient category and excessive in another area.

Barrels Can Be Cool Too.

In order to display Liebig’s Law, we engineered a special fountain for AgroLiquid’s IQhub. It consists primarily of a large barrel with uneven staves and a large base for catching water. The display shows how water naturally leaks from the lowest stave of the barrel, regardless of how high the others are. Water collects in the base below a turf of fake grass and pumps back into the barrel, allowing the fountain to remain constantly flowing. Liebig’s barrel demonstration offers a visual representation of how the lowest nutrient could be the limiting factor in plant growth, just as the lowest stave was the limiting factor in allowing the barrel to fill.

A separate display element housing a TV monitor shows a video that further illustrates Liebig’s barrel concept. It also provides some supplemental text and graphics explaining the law.

(Source: “Liebig’s Law of the Minimum”)