Essential element for the plant: yes! But what is it for and how do I use it? Potash is a potassium compound, used in most fertilizer formulas with phosphorus and nitrogen. The production and use of this element were widely spread thanks to Alsace potash mines throughout the 20th century. Although overall soils are today concentrated in potassium, especially in regions with volcanic and primary rocks, its effectiveness is often relative. And for good reason: this essential nutrient for the development of the plant, requires an optimal environment to offer the plant its full potential.
What is potash used for?
Indispensable for plant life, potash is used to directly stimulate cell formation and growth. Its functions in plant metabolism are multiple: activation of photosynthesis, opening of stomata, circulation of sap, etc.
Assessing potassium deficiencies
Assessing a potassium deficiency is the best way to ensure the suitability of a fertilizer formula made from potash. There are several possibilities for this: visual assessment or soil analysis. A potassium deficiency is characterized by poorly developed plants with leaf edges varying from yellow and brown, with a soft habit and a blade covered with brown spots. The appearance of diseases can also indicate a deficiency. Finally, the type of soil is also to be taken into account. A calcareous soil is often poorer in potassium. Although a visual assessment may be enough to raise a lack of potash, only soil analyzes offer a precise diagnosis for consuming fertilizers whose formula is specifically adapted to the needs of the crop.
Potash and other nutrients: interdependencies
The quantity of chemical fertilizers spilled over the past decades has generally enriched the potash soils, thus limiting deficiencies. However, the excess of fertilization products concentrated in potash, in turn led to deficiencies in calcium and magnesium. This makes plants more vulnerable to pests and diseases today.
As with nitrogen and phosphorus, potash must be used in a specific amount, according to the needs of the soil and plants. More importantly, the use of products made from potash should not fail to take into account the other essential nutrients for the plant: trace elements (boron, zinc, selenium, etc.) and macroelements (calcium, magnesium, etc.). This rule follows the logic of the following Liebig’s law: if one of the essential nutrients is missing, all the other nutrients present are useless.
Optimizing the potash’s efficiency therefore means spreading fertilizer solutions comprising all the elements that the soil and the plant need, in the right quantity. Indeed, putting too much or not enough potash, unbalances the action of phosphorus, nitrogen, macro-elements and trace elements. Ultimately, this imbalance does not allow the plant to take full advantage of the nutritional benefits of potassium.