Sadržaj razmenljivo-adsorbovanih katjona u krečnjačkim crnicama Rajca

The paper contains the results of the investigations of exchangeably adsorbed cation content in various subtypes of calcareous black soils from the area of Rajac, a north-east branch of the mountain Suvobor. A series of 17 representative samples of soil collected from four subtypes of calcareous black soil (organogenic, organo-mineral, brownized and loessivized black soil) has been analyzed. Contents of exchangeably adsorbed Ca2+, Mg2+, K+ and Na' have been determined by the method of atomic adsorption spectrophotometry. The results of the analyses have shown that in all analyzed samples of the calcareous black soil, the content of exchangeably adsorbed Ca2+ ions was the highest. It varies within the range of 53.3 (in organogenic black soil) to 15.3 meq (in loes­sivized black soil). The content of exchangeably adsorbed Mg2+ ions varies from 3.4 (in organo-mineral black soil) to 0.7 meq (in brownized black soil). The contents of exchangeably adsorbed Na+ and K+ ions in all investigated subtypes of calcareous black soils is lower than 1 meq. On the basis of the obtained results, it may be clearly seen that there occurred changes of exchangeably adsorbed caption content (especially of Ca2+ and Mg2+) through various evolution stages of the investigated calcareous black soil. .U radu su prikazani rezultati istraživanja sadržaja razmenljivo - apsorbovanih katjona u različitim podtipovima krečnjačke crnice sa područja Rajca, severoistočnog ogranka planine Suvobor. Analizirano je ukupno 17 reprezentativnih uzoraka zemljišta uzetih iz četiri podtipa krečnjačke crnice (organogena, organo - mineralna, braunizirana i lesivirana crnica). Metodom atomske apsorpcione spektrofotometrije određen je sadržaj razmenljivo - adsorbovanog Ca2+, Mg2+, K' i Na'. Rezultali analiza pokazali su da je najveći sadržaj u svim ispitanim uzorcima krečnjačke crnice razmenljivo - adsorbovanih Ca2+ jona, i varira u intervalu od 53.3 (u organogenoj crnici) do 15.3 m.ekv. (u lesiviranoj crnici). Sadržaj razmenljivo - apsorbovanih Mg2+ jona varira od 2.4 (u organo - mineralnoj crnici) do 0.7 m.ekv. (u brauniziranoj crnici). Sadržaj razmenljivo apsorbovanih Na' i K' jona u svim ispitanim podtipovima krečnjačke crnice je manji od l m.ekv.. Na osnovu dobijenih rezultata jasno se uočavaju promene sadržaja razmenljivo - apsorbovanih katjona (naročito Ca2+ i Mg2+) u različitim evolucionim fazama ispitane krečnjačke crnice