Role of Potassium

Potassium affects the life and life-style of every living being. Athletes often drench themselves with special nutrient fortified drinks to restore K lost with body fluids.

Potassium's role in plant growth is quite similar to that for humans. Potassium is not an integral part of any organic molecules in plants. K is important in many of the biochemical reactions of the plant including translocation of carbohydrates. Since it does not complex with organic compounds, it is only minimally related to the soil's organic matter.

K found in soils is from the weathering of minerals (Feldspars and Micas) that release K ions, which are than adsorbed onto CEC sites. Since potassium will weather from clay minerals, the more clay a soil has, the higher the amounts of potassium and the less fertilizer required.

K Deficiency Symptoms

Under severe deficiency, plants will often develop visible symptoms. For potassium the edges of older leaves will turn brown while yield and quality decline. Sometimes the signals are even more specific. For example, orange trees will drop their fruit; strawberries do not fully develop their sweet taste; corn stalks will break, sending ears to the ground; tomatoes will be small and contain too much white tissue. Alfalfa will show typical yellowing along the outer margins of the leaves.

This information was produced by "The University of Minninsota.

Potassium is also noted for increasing the stalk strength of many grain crops. Low K levels can lead to lodging (broken and fallen stalks) of corn. Maple leaves show K deficiency symptoms that are similar to corn--a burning of leaf edges.

Specialty crops such as turf for home lawns and golf courses also benefit from the wise use of K. It helps build in winter hardiness and tolerance to moisture stress, and increases plant regrowth vigor. Potassium improves disease resistance and durability under use. And it helps N produce the deep green color associated with healthy turf.

K Use by Plants

Crop uptake of potassium will depend on the type of crop, the amount of biomass that is being produced, and the soils ability to supply potassium.

Potassium deficiencies can be improved by using Jersey Greensand and Earth Juice, Meta-K

The earth's crust is loaded with potassium. Most mineral soils are high in potassium with the exception of sandy soils which, due to leaching, may have lost their potassium. (Remember, even cations will eventually leach if the soil has a low CEC.) In Minnesota, the farther west you go, the greater the native K in the soil.

K Fertilizer Program

Soil K is found in minerals like feldspars and micas (90% of total soil K). K is also fixed inside of clay minerals ( 9% of soil K) and is found on the soil exchange sites ( 1% of soil K). About 0.1% of the K at any one time is in the soil solution.

Management of potassium is especially important for soils with low CEC and where irrigation is used where leaching can readily occur. Potassium can be stored in the soil from one year to the next and thus, a build up of of potassium is possible from one year to the next. Persons who continually deposit wood ashes on their garden will build up their K levels and raise the soil pH.

Potassium is not a pollutant. Even if potassium is leached from soil, K does not cause environmental problems.