Nutrient Function in Plants
Nitrogen (N): The most used nutrient. It stimulates dark green vegetative growth and is involved with amino acids, protein, chlorophyll and genetic material. Nitrogen is made available by soil microbes.
• Deficiency: Older leaves are yellow. New leaves are
• Excess: Plant leaves burn with elongated growth, bud drop, poor fruit and flower production.
Phosphorus (P): Needed for seed, root, flower, and fruit growth. Essential for genetic material, membrane formation, and energy transfer. Soil pH should be between 6.0 and 7.0.
• Deficiency: Reddish to purple leaves. Stunted growth. Dark green leaves with tip burn. Poor fruit, flower, and root set.
• Excess: Restricts the availability of Zinc, Manganese and Iron.
Potassium (K): Improves overall plant vigor and disease resistance. Encourages root growth and fruit quality. Used for carbohydrate metabolism and cell division. Required for stomata guard cells, regulates absorption of calcium, sodium, and nitrogen. Helps roots withstand compacted soils.
• Deficiency: Plants exhibit chlorosis (loss of green color) along the leaf margins or tips, starting with the bottom leaves and progressing up the plant.
• Excess: Restricts availability of Magnesium and Boron.
Calcium (Ca): Stimulates root growth. It promotes firm, thick stems and helps to correct soil acidity. Needed for nitrogen uptake and protein synthesis. Must be present for cell walls and also plays a role in enzyme activation and cell reproduction.
• Deficiency: Symptoms appear in the meristem regions (new growth) of leaves, stems, buds and roots. Younger leaves are affected first and are usually deformed. In extreme cases, the growing tips die. Roots on calcium -deficient plants are short and stubby. In tomatoes and peppers, a black leathery appearance develops on the blossom end of the fruit (a disorder called blossom end rot).
• Excess: Restricts availability of magnesium, potassium, iron, zinc, phosphorus and boron.
Magnesium (Mg): Essential for chlorophyll production. Magnesium is necessary for phosphorus metabolism and enzyme activation. It enhances the production of oils and fars and facilitates the translocation of carbohydrates (sugars and starches). Some plants, such as citrus and roses, are heavy users.
• Deficiency: The predominant symptom is interveinal chlorosis (dark green veins with yellow areas between the veins). The bottom leaves are always affected first.
• Excess: Restricts availability of potassium, zinc, manganese, and boron.
Sulfur (S): Stimulates plant growth and seed formation. An essential element, sulfur is used in amino acids, proteins, and several vitamins. Sulfur will lower the pH in the soil.
• Deficiency: Characterized by stunted growth, delayed maturity and general yellowing of plants. Yellowed plants are also characteristic of nitrogen deficiency. However, unlike nitrogen deficiency—which begins in the older leaves and progresses up the plant—deficiency symptoms begin in the young, upper leaves first, often misdiagnosed as nitrogen problems.
• Excess: Can create acidic pH that can be toxic.
Iron (Fe): Promotes green color. Iron is essential for the formation of chlorophyll and is a constituent of various enzymes and proteins. It is restricted by pH and lime. Excess will restrict Zinc, Magnesium and
• Deficiency: Interveinal chlorosis of young leaves and twig die back.
• Excess: Restricts availability of Zinc and Manganese.
Manganese (Mn): Promotes plant maturity. Manganese acts as an enzyme activator for nitrogen assimilation. It is essential for the manufacture of chlorophyll. Low plant manganese, therefore, reduces the chlorophyll content causing leaves to turn yellow (chlorosis).
• Deficiency: Typically characterized by interveinal chlorosis (dark green veins with yellow discoloration between the veins), but symptoms vary depending on the plant.
• Excess: Iron is restricted.
Zinc (Zn): Part of the enzyme systems which regulate plant growth. It is essential for the transformation of carbohydrates and regulates consumption of sugar.
• Deficiency: The first obvious symptom of deficiency is interveinal chlorosis of the upper (youngest) leaves. Afterwards, shoot growth slows down.
• Excess: Restricts availability of iron, copper and manganese.
Copper (Cu): Important for reproductive growth and a catalyst for enzyme and chlorophyll synthesis. Aids in root metabolism and helps in the utilization of proteins.
• Deficiency: Symptoms generally appear on young plants. The first symptoms are yellowing of the youngest leaves accompanied by slightly stunted growth. In extreme cases, leaves become shriveled, twisted, broken, ragged and die.
Boron (B): Essential for seed, root and fruit development. Boron aids in production and transport of sugar and starch. Helps in the use of nutrients and regulates other nutrients.
• Deficiency: The first visible symptom of deficiency is death of the growing tips. This disorder is generally followed by growth of lateral shoots, which may also be deformed or die. Other symptoms include stunted roots, failure to set flowers.
Molybdenum (Mo): Is required for symbiotic nitrogen fixation (nodulation) by legumes and reduction of nitrates for protein synthesis.
• Deficiency: Symptoms are very similar to those of Nitrogen: pale-green to yellow leaves; yellow spots on leaves; marginal chlorosis alongside and tip of blade; thick cupped leaves. The marginal chlorosis exhibited by some plants looks similar to Potassium deficiency.
Chlorine (Cl): Aids plant metabolism. Chlorine is naturally found in the soil.
• Deficiency: Reduced growth; stubby roots; interveinal chlorosis; nonsucculent tissue (in leafy vegetables