固相萃取-离子色谱法测定土壤中游离态的K+、Na+、Ca2+、Mg2+
고상췌취-리자색보법측정토양중유리태적K+、Na+、Ca2+、Mg2+
Determination of dissociative K+,Na+,Ca2+and Mg2+ in soil by SPE-ion chromatography