Published 2013
14
Potassium and Phosphorus
Research in Turfgrass
Kevin W. Frank*
Elizabeth A. Guertal
P
otassium is an essential element for plant growth, and is required by
plants in relatively large amounts (McCarty, 2005). It is taken up from the
soil solution by plant roots in the form of the potassium ion. The element
is mobile in the plant, with symptoms of deficiency appearing first in the
lower leaves (Tisdale et al., 1991). Potassium is directly involved in enzyme activation, maintenance of water status, energy relations, translocation of assimilates,
and protein synthesis. In water relations, potassium regulates cellular turgor
pressure to avoid wilt, in turn controlling the regulation of stomatal opening and
so greatly enhancing drought tolerance. Accumulation of inorganic solutes such
as potassium increases osmotic adjustment, which is responsible for the regulation of guard-cell turgor and stomatal aperture. Accounting for 59 to 65% of
the total ion concentration, potassium is the most prevalent ion solute in cell sap
(Jiang and Huang, 2001).
Because potassium is considered the plant nutrient needed in the secondgreatest quantity by turfgrasses, research on the element in turfgrass systems has
often examined its perceived role in the mitigation of turf stress. Early research
demonstrated that plants exhibit “luxury consumption” of potassium, that is,
they take up more of the element than is needed for growth or reproductive
needs (Bartholomew and Janssen, 1929). Interactions of potassium with nitrogen
or other cations in turfgrass systems have also been studied. Unlike phosphorus and nitrogen, the environmental impacts of potassium fertilization are less
frequently studied because the nutrient is viewed as a benign factor in the environmental quality of landscapes that surround turfed areas.
K.W. Frank, Dep. of Crop and Soil Sciences, Michigan State Univ., 584E Plant and Soil Sciences, East
Lansing, MI 48824 ([email protected]), *corresponding author; E.A. Guertal, Dep. of Agronomy and
Soils, Auburn Univ., 253 Funchess Hall, Auburn, AL 36849 ([email protected]).
doi:10.2134/agronmonogr56.c14
Copyright © 2013. American Society of Agronomy, Crop Science Society of America, Soil Science
Society of America, 5585 Guilford Road, Madison, WI 53711, USA. Agronomy Monograph 56.
Turfgrass: Biology, Use, and Management. John C. Stier, Brian P. Horgan, and Stacy A. Bonos, editors.