Article: Soil fertility basics. (The garden).

The major nutrients required by plants can be divided into two basic groups, cations and anions.

Cations are ions (atoms) that carry a positive charge. The major cation nutrients, which are used in relatively large quantities by plants, are potassium (K), calcium (Ca), and magnesium (Mg). Soil clay particles and organic matter (OM) contain negatively charged "exchange sites," which attract and hold these cations. The cation exchange capacity (CEC) is a measure of a soil's ability to attract cations and keep them in an exchangeable form. These cations drift back and forth between the soil and organic matter particles and the soil water solution. A soil with a high ...

Related newspaper, magazine, and journal articles:

 
 
Newsweek Harper's Magazine The Washington Post Chicago Tribune Crain's Chicago Business PRNewswire Pediatric News The Nation Advertising Age The Economist (US) A FREE trial gives you access to over 80 million articles! Access over 6,500 publications with a FREE trial!