UTJECAJ KALCIZACIJE NA PRISTUPAČNOST TEŠKIH METALA U TLU

The aim of this paper was to determine the influence of acid soils liming and initial soil acidity as well as organic matter content on availability of four heavy metals m(Zn, Pb, Cr and Cd). Liming experiment was conducted in laboratory conditions with six soils of different acidity according to rapid incubation method which was conducted in sealed containers for three days at a constant temperature of 60°C. Liming treatments resulted in trend of heavy metals availability decrement in all soils, but intensity of decrement differed considering initial soil acidity and initial heavy metals availability. According to relative heavy metals availability decrement, liming resulted in the strongest effect in extremely acid soils with the highest initial concentrations of available Zn, Pb, Cr and Cd. On the other side, the weakest relative liming effect on heavy metals availability decrement was recorded in moderately acid soils with the lowest initial concentrations of available heavy metals. Considering impact of initial humus content in soil, higher relative liming efficiency of heavy metals availability decrement was determined in soils with higher soil organic matter content and with lower initial concentrations of available heavy metals.
Cilj je rada bio utvrditi učinak kalcizacije kiselih tala na promjenu pristupačnosti teških metala Zn, Cr, Pb i Cd, s obzirom na različitu kiselost tla i sadržaj organske tvari. Pokus kalcizacije proveden je na šest eksperimentalnih tala različite kiselosti u četiri ponavljanja, uz inkubaciju u zatvorenim posudama tijekom tri dana, uz konstantnu temperaturu od 60°C. Tretmani kalcizacije rezultirali su trendom smanjenja pristupačnosti teških metala u analiziranim tlima, ali se intenzitet smanjenja razlikovao ovisno o početnoj kiselosti tla te inicijalnoj pristupačnosti teških metala. Na temelju relativnoga smanjenja pristupačnosti teških metala, najveći učinak kalcizacije zabilježen je u ekstremno kiselim tlima, s najvećom inicijalnom koncentracijom pristupačnog Zn, Pb, Cr i Cd. Nasuprot tome, najslabiji relativni učinak kalcizacije utvrđen je u umjereno kiselim tlima s najnižom početnom razinom pristupačnosti teških metala. S obzirom na početni sadržaj humusa u tlu, veći učinak kalcizacije na relativno smanjenje pristupačnosti Zn, Pb, Cr i Cd, utvrđen je na tlima s višim sadržajem humusa i nižom početnom razinom pristupačnosti teških metala.