Plant nutrition

Plant nutrition is the study of the chemical elements and compounds necessary for plant growth, plant metabolism and their external supply. In 1972, E. Epstein defined two criteria for an element to be essential for plant growth: in its absence the plant is unable to complete a normal life cycle or that the element is part of some essential plant constituent or metabolite. This is in accordance with Justus von Liebig's law of the minimum. The total essential plant nutrients include seventeen different elements: carbon, oxygen and hydrogen which are absorbed from the air, while other nutrients including nitrogen are typically obtained from the soil (exceptions include some parasites or carnivorous plants).

There are several principles that apply to plant nutrition. Some elements may be readily available in the soil but not accessible to plants because of a lack of soil solution. Others may not be mobile in the plant and therefore the plant can develop a deficiency in that specific element resulting in a deficiency symptom. It is also possible for some elements to be excessively available to plants and then become toxic. Furthermore, each element must be available in a form that the plant can take up via the plant root system.

Essential nutrients

Each of the elements that a plant needs has a specific role. No one element can substitute for another. There are seventeen essential elements necessary for plant growth. Carbon, oxygen, and hydrogen are found in air and water. Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, iron, manganese, zinc, copper, molybdenum, and nickel are derived from soil.

Soil fertility

Soil fertility is the capacity of soil to provide nutrients in adequate amounts and in proper balance for the growth of specified plants when other growth factors, such as light, temperature, and moisture, are favorable.

Nutrient deficiency

If soil is deficient in one or more nutrients, plants may exhibit symptoms of nutrient deficiency. A plant's ability to absorb nutrients from the soil is affected by the pH of the soil, the soil texture, the presence of other nutrients, and the temperature of the soil.

See also

• Soil science
• Hydroponics
• Fertilizer
• Nutrient management

References

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