Potassium Overview

Technical Update


Potassium is an essential component of plant nutrition. Potassium deficient plants are known to be less resistant to plant diseases.

Key functions in the plant

  • Maintenance of water balance in the plant, helps regulate cell water content and plant turgor, maintaining stem strength
  • Important role in transpiration by controlling stomatal pore opening and closing
  • Good mobility in the plant
  • There are 4 pools of potassium in the soil, most are in soil minerals. These weather to release slowly available potassium embedded in clays, readily available potassium held on the surface of clays, organic matter and potassium in soil solution

Factors affecting availability to plant

  • Low pH soils
  • Deficiency can be common at the end of the growing season, especially on light, sandy soils
  • Soils with low clay reserves where little K is released, and on sandy or light soils where K can be leached
  • Drought and high levels of magnesium reduce uptake