Potassium (K) plays a very vital role in the health and growth of a plant. It is one of the three most important essential elements of the 17 elements that are essential for plant life. Potassium, along with nitrogen and phosphorus, is one of the six macro elements for plant growth. Potassium plays many different roles in the health and look of a plant. These roles and functions are very well known. It improves how well the plant is able to grow, and it even helps to produce more plants as well. However, it isn’t necessarily perfectly understood why or how it is able to perform the functions that it does.
What is known about the roles that potassium plays in plant is that it is very closely associated with movement of water, nutrients, and carbohydrates in the tissue of plant cells and amongst them. If there is not enough potassium available for the plant to take up through its roots, then many of these roles will be adversely affected as well as growth in general is slowed down and the amount yielded is significantly lowered. Potassium has been shown to stimulate early growth in plants. It plays a metabolic role in the production of proteins as well. The making of these proteins helps to provide the plant with structure and strength as it grows.
Not only does it help to create and generate proteins which are useful for the plant to grow and flourish, it also helps to boost how efficient the plant is in its use of water. The more efficient a plant is with water, and the more proteins that are available for the plant to use makes for a perfect combination for a plant to reach its full growth potential. And as it grows, if there is enough potassium consistently available, the plant will be more able to withstand different environmental factors. Plants with enough potassium are better able to stand persistently, last longer and better withstand the cold of winter. It also improves resistance to diseases and insects.
Potassium is vital for the process of photosynthesis, and if there is not enough potassium present in the system, the process of photosynthesis will be extremely slowed. It will decline severely, and growth will be stunted heavily. However, as we have discussed in previous blogs, it can be highly difficult to diagnose an element deficiency based solely on the fact that growth is stunted or slowed down. A deficiency in several different elements or any combination of any others could be a root cause for reduced growth.
Some crops show some of the deficiency symptoms when there is sufficient levels of K are in short supply. Because of the fact that K is mobile in plants, it starts in the lower portion of the plant or crop and will progressively move upward towards the outer ends of the plants. For example, in corn, the margins of the lower leaves turn brown in the beginning of the deficiencies. Dead tissue can also start to develop if there is a deficiency and eventually, the entire leaf can become a very distinct light green when viewed at a distance.
What makes it so distinct to a K deficiency? How can you tell that it is potassium that your plant or crop needs? After all, the striping of the leaves that is closely tied with K deficiency in corn is easily confused with deficiency symptoms for sulfur, magnesium and zinc. The margins of the leaflets turn light green and eventually turn yellow when there is not enough K present in the production of soybeans. Or in alfalfa, there can be a number of small white or yellow dots that start to appear on the leaf margins, which continue to grow and develop until the entire outer leaf margin is entirely discolored. A deficient level of potassium adversely affects the root systems. A plant that is low in potassium will show poorly developed root systems, as well as weakness in the stalks or stems. Also, seed and fruits will be smaller and shriveled.