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The function and deficiency symptoms of plant essential nutrients

May 26,2015

The function and deficiency symptoms of plant essential nutrients


Major nutrients.

Nitrogen (N) is often required in the greatest quantity by crops, primarily for vigor and yield. Nitrogen plays a key role in chlorophyll production and protein synthesis. Chlorophyll is the green plant pigment responsible for photosynthesis. When nitrogen is deficient, plants develop yellow or pale leaves and their growth is stunted.

Phosphorus (P), is a vital component of adenosine triphosphate (ATP) which supplies the energy for many processes in the plant.  Phosphorus rarely produces spectacular growth responses, but is fundamental to the successful development of all crops. For example, maize or other corn crops that lack phosphorus during the growing season achieve lower yields.

Potassium (K) is needed by virtually all crops and often in higher rates than nitrogen. Potassium regulates the plant’s water content and expansion. It is key to achieving good yield and quality in cotton and critical for increasing the size, juice content and sweetness of fruit.


Three secondary nutrients needed at lower levels than NPK.

calcium (Ca) is perhaps the most important. Calcium strengthens cell walls, helping to reduce bruising and disease in fruit, salad and vegetable crops. This means that a good supply of calcium produces food crops that are less prone to damage and have a longer shelf life. Crops short in calcium will have growth disorders such as corky skin.

Fruit and vegetables containing higher levels of calcium also have

Higher nutritional value – for example, vitamin C and antioxidants in omatoes. This means that eating fresh fruit with strong skins and a great, crisp bite will help provide us with the calcium we need for strong bones.


Magnesium (Mg) is also important for crop quality, but is also a key component of leaf chlorophyll and the enzymes that support plant growth. Low magnesium leads to reduced photosynthesis, which severely limits crop yields.

Grain fill in rice and dry matter content of potatoes can be significantly reduced if magnesium is undersupplied.

Sulfur (S) is an essential part of many amino acids and proteins. Without both S and Mg, crops suffer; growth slows and leaves turn pale or yellow. Sulfur is particularly important for ensuring the protein content of cereal crop grains. 


Most micronutrients influence growth. 

For example, manganese (Mn), iron (Fe) and copper (Cu) all influence photosynthesis, the process whereby plants use sunlight for growth. 

Iron deficiencies are common – for example in seed fruits – where the effect is to reduce production of chlorophyll.  As a result, crops struggle and younger leaves develop a severe yellowing or chlorosis. 

Boron (B) is needed for the development of shoots and roots, and is essential during the flowering and fruiting phases of crops.

Zinc (Zn) is needed for the production of important plant hormones, like auxin. Zinc deficiency leads to structural defects in leaves and other plant organs.

Molybdenum (Mo) is involved in plant enzyme systems that control nitrogen metabolism.