Assertion: calcium ion | /r/CapableOf | attract to negative exchange sites
Facets:
value: on organic matter
type: LOCATION
value: on clays
type: LOCATION
Source sentences:
text: All soils contain calcium ions (Ca 2 +) and magnesium (Mg 2 +) cations (positively charged ions) attracted to the negative exchange sites on clays and organic matter (cation exchange complex of the soil).