Phosphorous in agriculture

Similar to my last post about nitrogen, this post is about another very important plant nutrient – phosphorous. Phosphorous is known to be a major plant nutrient together with Nitrogen and Potassium and is used very frequently in agriculture, be it conventional or organic agriculture. In this article I am going to briefly introduce the role of phosphorous in plants and agriculture, and also focus on aspects on how to use this important nutrient in a sustainable way.

Part 1 – What is the function of phosphorous in plants?

Phosphorous plays an important role in structural elements as well as energy transfer in all life forms [1]. In the DNA (and RNA) molecule, phosphorous binds together the bases (nucleotides), whose order defines the function of the derived protein. In cell membranes phosphorous is part of the so called phospholipids. These are molecules with a hydrophobic and a hydrophilic end. This property contributes to the formation of the bilayer membrane of cells, allowing different concentrations of many ions and molecules inside and outside the cell.  Beyond these structural functions, phosphorous has a crucial role in energy transfer. The synthesis of starch is fueled by the adenosintriphosphate (ATP) molecules, which is also involved in many other reactions in cells, acting as a principal energy transfer molecule.

As the name implies ATP contains a chain of three phosphate groups. During the energy transfer, one phosphate group is being cleaved off, releasing energy which can be used for the synthesis of other compounds (in plants notably starch) or to transport molecules (notably ions) across membranes. The resulting adenosindiphosphate (ADP) can then be recycled to form ATP again.

In seeds (e.g. grains, legumes), another famous phosphorous containing compound is used as energy storage – phytate. Phytate is the salt of phytic acid and typically associated with calcium, magnesium and potassium ions. However, phytic acid also has a high affinity for zinc and iron, which contributes to the controversy around phytic acid in nutrition, since it can inhibit the absorption of these micronutrients [2]. In germinating plants, the stored phosphorous can be accessed by breaking down the phytate with the enzyme phytase. This has also practical implications for nutrition, as activating seeds by soaking them can reduce phytate content. 

This was just a brief introduction to this interesting but complex topic. Stay tuned for the next parts addressing other important questions around phosphorous!


[1] Marschner, H. (2011). Marschner’s mineral nutrition of higher plants. Academic press.

[2] Torre, M., Rodriguez, A. R., & Saura‐Calixto, F. (1991). Effects of dietary fiber and phytic acid on mineral availability. Critical Reviews in Food Science & Nutrition, 30(1), 1-22.


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