Determination of cation axchange capacity in East Croatia soils by ammonium acetate method

Kationski izmjenjivački kapacitet (KIK) važno je mjerilo u pedologiji za procjenu fizikalno-kemijskog stanja tla, što može biti dobar pokazatelj kakvoće i produktivnosti tla. Laboratoriji obično ne provode izravno mjerenje KIK-a. Umjesto toga, često se KIK izračunava na temelju količina baznih kationa (Ca2 +, Mg2+, K + i Na +) ekstrahiranih u standardnim analizama tla (npr. amonijev acetat). Istraživanje je provedeno na 60 lokacija i 4 tipa tla (eutrično smeđe, lesivirano, aluvijalno tlo i ritska crnica) u istočnoj Hrvatskoj, uključujući samo oranične horizonte (dubina 0-30 cm). Uzorci tla (60) analizirani su na sljedeće parametre: pH, organska tvar, sadržaj gline, bazni kationi (Ca2+, Mg2+, K+ i Na+), hidrolitička kiselost i KIK. Agrokemijska i agrofizikalna svojstva unutar pojedinih pedosistematskih jedinica su bila izrazito heterogena sa širokim rasponom vrijednosti po svim svojstvima. Prosječne utvrđene vrijednosti KIK-a kretale su se od 15,50 do 36,39 cmol (+) kg-1, sadržaj humusa od 1,97 do 4,94 %, supstitucijska kiselost od 4,22 do 7,48 pH jedinica a sadržaj čestica gline od 7,14 do 34,92%. Sastav kationa na adsorpcijskom kompleksu je Ca> Mg> K> Na. Utvrđivanje vrijednosti KIK-a bi trebao postati važna analitička metoda u kontroli plodnosti tla kao i u monitoringu stanja poljoprivrednog zemljišta.The cation exchange capacity (CEC) or sum of exchangeable cations are an essential measurement in soil science to estimate the physico-chemical state of a soil, which may be a good indicator of soil quality and productivity. Soil testing laboratories do not usually provide a direct measure of CEC. Instead, often the CEC is calculated based on the quantities of base cations (Ca2+, Mg2+, K+ and Na+) extracted in the standard soil test (e.g. ammonium acetate). The study was conducted on 60 locations and 4 soil types (Eutric Cambisol, Luvisol, Fluvisol and Humic Gleysols) in Eastern Croatia including only topsoil horizon (depth 0-30 cm). The soil samples (60) were analyzed for the following parameters: pH, organic matter, clay content, base cations (Ca2+, Mg2+, K+ and Na+), hydrolytic acidity and CEC. Agrochemical and agrophysical properties were extremely heterogeneous with a wide range of values across all properties. Average determined CEC values ranged from 15.50 to 36.39 cmol (+) kg-1, organic matter content from 1.97 to 4.94%, exchangeable acidity from 4.22 to 7.48 pH units and clay from 7.14 to 34.92 %. The composition of the cations on the adsorption complex is Ca> Mg> K> Na. Determining the value of CEC should become an important analytical method in controlling soil fertility as well as in monitoring the condition of agricultural land