Leaching of microelement contaminants in a long-term field study

A field experiment with microelement loads was set up on loamy-textured, calcareous chernozem soil formed on loess. The ploughed layer contained about 5% CaCO3 and 3% humus. The soil was well supplied with Ca, Mg, Mn and Cu, moderately supplied with N and K, and weakly supplied with P and Zn. The water table is at the depth of 15 m, the water-balance of the area is negative, and the site is drought-sensitive. Salts of the 13 examined microelements were applied at 4 levels in the spring of 1991.Treatments were arranged in split-plot design, in a total of 104 plots with two replications. Loading rates were 0, 90, 270 and 810 kg/ha per elements in the form of AlCl3, NaAsO2, BaCl2, CdSO4, K2CrO4, CuSO4, HgCl2, (NH4)6Mo7O24, NiSO4, Pb(NO3)2, Na2SeO3, SrSO4, and ZnSO4. Soil profiles of the control and the 810 kg/ha treatment were sampled in the 3rd, 6th and 10th year of the trial. The mixed samples, consisting of 5 cores/plot, were taken every 30 cm to the depth of 60 (1993), 90 (1996) and 290 (2000) cm. NH4-ac...