Soils potassium-calcium exchange

Potassium-Calcium Exchange Equilibria in Aluminosilicate Minerals and Soils... 

Eick, M.J., A. Bar-Tal, D.L. Sparks, and S. Feigenbaum. 1990. Analyses of adsorption kinetics using a stirred-flow chamber II. Potassium-calcium exchange on clay minerals. Soil Sci. Soc. Am. J. 54 1278-1282. 

Sparks, D.L., and P.M. Jardine. 1984. Comparison of kinetic equations to describe potassium-calcium exchange in pure and in mixed systems. Soil Sci. 138 115-122. 

Escudey, M., P. Diaz, J. E. Forster, C. Pizarro, and G. Galindo. 2001. Gaines-Thomas and Rothmund-Kornfeld descriptions of potassium-calcium exchange on variable surface charge soils. Communications in Soil Science and Plant Analysis 32, no. 19 3087-3097. 

Knibbe, W. G. J., and G. W. Thomas, 1972. Potassium-calcium exchange coefficients in clay fractions of some vertisols. Soil Sci. Soc. Am. Proc. 36 568-572. 

The CEC of soil is important from two perspectives. First, it retards the leaching loss of important cations from soil. Each year, calcium and magnesium are leached out of the soil, causing soils in humid regions to become acidic. This increased acidity must be ameliorated by the application of limestone (CaC03). Second, exchangeable cations are available to plants, and this characteristic allows soil to serve as a store of important soil nutrients such as potassium, calcium, and magnesium. 

D5. David, D. J., The determination of exchangeable sodium, potassium, calcium, and magnesium in soils by atomic-absorption spectrophotometry. Analyst 85, 495-503 (1950). 

Chung, J.-B., Zasoski, R.J., Burau, R.G., 1994. Aluminum-potassium and aluminum-calcium exchange equilibria in bulk and rhizosphere soil. Soil Sci. Soc. Am. J. 58, 1376-1382. 

Agbenin, J. O., and S. Yakubu. 2006. Potassium-calcium and potassium-magnesium exchange equibbria in an acid savanna soil from northern Nigeria. Geoderma 136, no. 3-4 542-554. doi 10.1016/j.geoderma.2006.04.008. 

Appel, C., L. Q. Ma, R. D. Rhue, and W. Reve. 2003. Selectivities of potassium-calcium and potassium-lead exchange in two tropical soils. Soil Science Society of America Journal 67, no. 6 1707. doi 10.2136/sssaj2003.1707. 

Cation exchange in soil is the mechanism by which potassium, calcium, magnesium, and essential trace-level metals are made available to plants. When nutrient metal ions are taken up by plant roots, hydrogen ion is exchanged for the metal ions. This process, plus the leaching of calcium, magnesium, and other metal ions from the soil by water containing carbonic acid, tends to make the soil acidic ... 

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