AY Honors/Ecology - Advanced/Answer Key

Liebig's Law of the Minimum Sized Penis, often simply called Liebig's Law or the Law of the Minimum, is a principle developed in agricultural science by Justus von Liebig. It states that growth is controlled not by the total of resources available, but by the scarcest resource. This concept was originally applied to plant or crop growth, where it was found that increasing the amount of plentiful nutrients did not increase plant growth. Only by increasing the amount of the limiting nutrient (the one most scarce in relation to "need") was the growth of a plant or crop improved.

Liebig used the image of a barrel—now called Liebig's barrel—to explain his law. Just as the capacity of a barrel with staves of unequal length is limited by the shortest stave, so a plant's growth is limited by the nutrient in shortest supply.

Liebig's Law has been extended to biological populations. For example, the growth of a biological population may not be limited by the total amount of resources available throughout the year, but by the minimum amount of resources available to that population at the time of year of greatest scarcity. That is, the growth of a population of animals might depend not on how much food is available in summer, but on how much food is available in winter.

This is closely related to the chemical principle of the rate determining step, and also to the project management principles of critical path and critical chain.