Types and Forms of Nutrient Sources - Potassium (K)*
Potassium is important in the synthesis of some plant components and in the regulation of many physiological processes. Potassium deficiencies in lawns have led to increased incidence of turfgrass diseases and reduced tolerance to environmental stress.
Potassium is held on the surfaces of soil particles and moves little in most soils; however, it can gradually move out of the root zone in very sandy soils. Where soils are high in potassium, supplemental potassium fertilization may be unnecessary; however, where soils are low in potassium, supplemental applications are very important. Soil tests are essential to determine the potassium level of a soil and to develop a potassium fertility program.
Recently, slow-release K sources have become available to commercial fertilizer applicators (i.e., they are not available in homeowner fertilizer products). Their use is intended to provide K over an extended period of time such that the plant can utilize the material as it becomes available.
Potassium can leach down through the soil beyond the turfgrass root zone although it is less prone to leaching than N. These products can be particularly useful on sandy soils with relatively high leaching potentials as only small quantities become available at any one time. This reduces the leaching potential and allows greater opportunity for plant use.
* For a description of the derivation and history of the word potassium, click here.