Nutrition
Plant nutrition
Plants require a set of essential nutrients to grow. This overview introduces those nutrients and the principles of managing them; specific fertilizer rates always depend on soil tests and local guidance.
Essential nutrients
Beyond carbon, hydrogen, and oxygen from air and water, plants require a number of mineral nutrients, conventionally divided by the amounts needed.
- Macronutrients — needed in larger amounts: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S).
- Micronutrients — needed in small amounts: iron, zinc, manganese, boron, copper, molybdenum, chlorine, and nickel.
Nitrogen, phosphorus, and potassium are the nutrients most often managed through fertilization, but a deficiency in any essential nutrient can limit growth.
Fertilizer categories
- Organic sources — such as manures, composts, and crop residues, which supply nutrients and organic matter as they break down.
- Mineral (inorganic) fertilizers — manufactured products supplying nutrients in defined, readily available forms.
Managing nutrients responsibly
Sound nutrient management matches supply to crop demand, drawing on soil testing and the nutrients already present in the soil and from previous crops. Applying the right source, at the right rate, time, and place helps crops while reducing losses to water and air.
Because the correct rates depend on the crop, soil, yield goal, and local regulations, AgricultureID does not publish universal fertilizer recommendations. See individual crop and soil entries for context.
Essential nutrients A–Z
In-depth entries for each essential plant nutrient — roles, deficiency and toxicity symptoms, interactions, and the fertilizers that supply them.
17 entries
- Plant nutrient
Boron
Boron is a micronutrient required for cell wall formation and for reproductive development, including pollen tube growth and seed set. It has an unusually narrow range between deficient and toxic soil levels.
- Plant nutrient
Calcium
Calcium is a secondary macronutrient essential for cell wall structure and membrane stability. Because it moves within the plant only in the transpiration stream, calcium-related disorders often appear in fast-growing tissue even when soil calcium is adequate.
- Plant nutrient
Chlorine
Chlorine, taken up as the chloride ion, is a micronutrient involved in osmotic regulation, photosynthesis, and disease suppression in some crops. It is rarely deficient in the field but can reach excess, growth-limiting levels under saline conditions.
- Plant nutrient
Cobalt
Cobalt is a beneficial element not required by most plants directly, but essential to the rhizobia bacteria that fix atmospheric nitrogen in legume root nodules, making it agronomically important wherever symbiotic nitrogen fixation drives crop nutrition.
- Plant nutrient
Copper
Copper is a micronutrient required for several enzyme systems, including those involved in lignin synthesis and reproductive development. Deficiency is concentrated on organic (peat) and sandy soils where copper is poorly available.
- Plant nutrient
Iron
Iron is a micronutrient required for chlorophyll synthesis and for enzymes involved in respiration and photosynthesis. Its availability falls sharply as soil pH rises, making iron deficiency chlorosis a common problem on calcareous soils.
- Plant nutrient
Magnesium
Magnesium is a secondary macronutrient at the centre of every chlorophyll molecule and a cofactor for many plant enzymes. Deficiency commonly appears as interveinal yellowing of older leaves, especially on light, acidic, or potassium-rich soils.
- Plant nutrient
Manganese
Manganese is a micronutrient essential to the water-splitting step of photosynthesis and to several other enzyme systems. Its availability is unusually sensitive to soil pH and drainage, making it prone to both deficiency and toxicity depending on conditions.
- Plant nutrient
Molybdenum
Molybdenum is a micronutrient required in the smallest amounts of any essential element, but it is essential for nitrogen fixation and nitrate metabolism. Unlike most micronutrients, its availability increases with soil pH, so deficiency is concentrated on acidic soils.
- Plant nutrient
Nickel
Nickel is the most recently recognised essential plant micronutrient, required in trace amounts as a cofactor for the enzyme urease. Its requirement is so small that deficiency is rarely observed under typical field conditions.
- Plant nutrient
Nitrogen
Nitrogen is a primary macronutrient central to plant growth, forming part of amino acids, proteins, and chlorophyll. It is the nutrient most often limiting yield and the one most widely managed through fertilization.
- Plant nutrient
Phosphorus
Phosphorus is a primary macronutrient essential for energy transfer, root development, and reproductive growth. Plants take it up from soil as phosphate ions, which are often poorly available and must be carefully managed.
- Plant nutrient
Potassium
Potassium is a primary macronutrient that regulates water relations, enzyme activation, and the movement of sugars within the plant. It is required in amounts similar to nitrogen but, unlike nitrogen, is not part of any organic plant compound.
- Plant nutrient
Silicon
Silicon is a beneficial element that strengthens plant tissue by depositing within cell walls, improving resistance to lodging, pests, and disease, with the clearest and most consistent responses seen in grasses such as rice and sugarcane.
- Plant nutrient
Sodium
Sodium is a beneficial, largely functional element rather than an essential nutrient for most crops. A small group of "natrophilic" species, notably sugar beet, respond positively to sodium, while excess sodium in soil is a separate and generally harmful concern.
- Plant nutrient
Sulfur
Sulfur is a secondary macronutrient required for the amino acids cysteine and methionine and therefore for protein synthesis. Its behaviour in soil closely parallels nitrogen, and deficiency has become more common as atmospheric sulfur deposition has declined.
- Plant nutrient
Zinc
Zinc is a micronutrient that activates numerous plant enzymes and is required for the synthesis of the growth hormone auxin. It is among the most widespread micronutrient deficiencies worldwide, particularly on high-pH and calcareous soils.
Sources
This article draws on the following authoritative sources. See our sources & methodology for how they are selected.
- [1]FAO — Food and Agriculture Organization (opens in a new tab)Authoritative
Food and Agriculture Organization of the United Nations (FAO)
Cited for: Plant nutrition and fertilizer use
- Type:
- Intergovernmental organization
- Jurisdiction:
- Global
- Accessed:
- 2026-07-12
- [2]USDA NRCS — Natural Resources Conservation Service (opens in a new tab)Authoritative
USDA Natural Resources Conservation Service (NRCS)
Cited for: Nutrient management principles
- Type:
- Government agency
- Jurisdiction:
- United States
- Accessed:
- 2026-07-12
- [3]AHDB — Agriculture and Horticulture Development Board (opens in a new tab)High
Agriculture and Horticulture Development Board (AHDB)
Cited for: Nutrient management guidance context
- Type:
- Government agency
- Jurisdiction:
- United Kingdom
- Accessed:
- 2026-07-12