Liebig's important contribution, in spite of the above misconceptions, was to express the earlier concept of mineral balance proposed by Sprengel (1787-1859), which he formulated as the Law of the Minimum (Browne, 1942). This states that if one of the plant nutrients is present in the soil in a state of deficiency or unavailability, it will render the other nutrients inactive or lessen their activity. There are limitations to this rule, and later experiments showed that some plants will still grow using an incomplete fertilizer, but the yield will be diminished and the crop contain a deficiency of the omitted element. Other growth factors such as rainfall, sunshine and temperature should also be taken into account when defining conditions to achieve the optimum yield. Balance was later expressed as the general principle of multi-causation in nature, and more recently as that of taking a holistic view of the soil-plant ecosystem, including the soil microbial population.

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