Together with P and N it is the third most important element in plants. Potassium is absorbed by the plant in its K + cationic form and plays an essential role in plants as it is the main activator of numerous enzymes (among them kinases, transferases, synthetases, etc.). In addition, it plays a key role in the plants’ cellular osmoregulation by intervening in the opening and closing of stomata. In order to do this, potassium increases resistance to drought and cold. It also intervenes in the transport of sugars by the phloem and is the most abundant cation in plants, which can represent up to 10% of its dry weight.

K in agriculture:

Potassium is a macroelement with very important agricultural applications, however, it is not an element of mobility or easy absorption by the plant. In fact, it has resorted to different complexing or chelating forms to replace the conventional contributions historically formed by potassium salts with a very low effectiveness and with many losses of the element in the soil.

It affects:

• Correct fruit formation. Incidence on maturation and on coloration.
• Improvement of production in fruit and tubers.
• Better post-harvest attitude.
• More root growth.
• Increase in drought and frost resistance.
• Reduction of the tendency to overturn in some crops.
• Increased nodulation in legumes.

Potassium deficiency: like N and P, K is a very mobile element and the symptoms of its deficiency are manifested first in the oldest leaves. It is characterized by the appearance of mottled and necrotic appearance on the tips and edges of the leaves. In general, they present a smaller size due to shortening of the internodes and given the important role in osmoregulation, they may suffer loss of turgor of the stomata and therefore greater susceptibility to water stress. Finally, the plant is more susceptible to attack by pathogens.

Several of the most frequent deficiencies in the field are found in tomato (characteristic chlorosis at the edges), citrus fruits (spots on the fruit), avocado (peripheral leaf spots and poor fruit formation).

Potassium Excess: In conditions of excess of K its consumption increases, and it can interfere in the uptake of calcium and magnesium indirectly causing a deficiency of Ca or Mg.