College of Agriculture & Life Sciences Publications and Scholarship


Potassium in Mississippi Soils


Potassium (K) is absorbed in large amounts by plants. Potassium uptake by crops under good growing conditions is high, often equal to nitrogen (N) uptake. Potassium is used in photosynthesis, sugar transport, water and nutrient movement, protein synthesis, and starch formation by plants. Adequate potassium in plants increases disease resistance, water stress tolerance, winter hardiness, tolerance to plant pests, and uptake efficiency of other nutrients.

Potassium mobility is often related to soil texture: movement is greatest in soils with more sand content. The buildup of potassium in soils is related to soil texture, with the greatest accumulation generally in clay soils, followed by loam and coarse-textured sands.

Although soils provide a great deal of potassium through natural processes, fertilization with potassium may be necessary to maximize plant growth. The total amount of potassium in soil ranges from 5 to 25 tons per acre. While this seems like a lot of potassium, only a small amount is plant-available at a particular point in time. Most potassium is in the structural component of the soil. Sandy-textured soils have much less potassium than fine-textured, clay soils. Where levels of soluble potassium in the soil are high, plants may take up more potassium than needed in a “luxury consumption” that does not increase yields.


Mississippi State University Extension

Publication Date


Spatial Coverage

Mid-South United States


College of Agriculture and Life Sciences


Department of Plant and Soil Sciences

Research Center

Mississippi State University Extension Service


Mississippi State University Extension Service


potassium, soil fertility, plant nutrition, nutrient management, fertilizer


Agriculture | Agronomy and Crop Sciences

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