Soil acidity and mobile aluminum status in pseudogley soils in the Čačak-Kraljevo Basin

Soil acidity and aluminum toxicity are considered the most damaging soil conditions affecting the growth of most crops. This paper reviews the results of tests of pH, exchangeable acidity and the mobile aluminum (Al) concentration in profiles of pseudogley soils from the Čačak-Kraljevo Basin. For these purposes, 102 soil pits were dug in 2009 in several sites around the Čačak-Kraljevo Basin. The tests encompassed 54 field, 28 meadow, and 20 forest soil samples. Samples of soil in a disturbed state were taken from the Ah and Eg horizons (102 samples), from the B1tg horizon in 39 field, 24 meadow and 15 forest pits (a total of 78 samples) and from the B2tg horizon in 14 field, 11 meadow, and 4 forest pits (a total of 29 samples). The mean pH values (1 M KCl) of the tested soil profiles were 4.28, 3.90 and 3.80 for the Ah, Eg and B1tg horizons, respectively. The soil pH of the forest samples was lower than those in the meadow and arable land samples (mean values of 4.06, 3.97 and 3.85 for arable land, meadow and forest samples, respectively). The soil acidification was especially intensive in the deep horizons; thus, 27 (Ah), 77 (Eg) and 87 % (B1tg) of the soil samples had a pH value below 4.0. The mean values of the total exchangeable acidity (TEA) were 1.55, 2.33 and 3.40 meq (100 g)-1 for the Ah, Eg and B1tg horizons, respectively. The TEA values in the forest soils were considerably higher (3.39 meq (100 g)-1) than those in the arable and meadow soils (1.96 and 1.93 meq (100 g)-1, respectively). The mean mobile Al contents of the tested soil samples were 11.02, 19.58 and 28.33 mg Al (100 g)-1 for the Ah, Eg and B1tg horizons, respectively. According to the pH and TEA values, mobile Al was considerably higher in the forest soils (a mean value of 26.08 mg Al (100 g)-1) than in the arable and meadow soils (mean values of 16.85 and 16.00 mg Al (100 g) -1, respectively). The Eg and B1tg horizons of the forest soil had especially high mobile Al contents (mean values of 28.50 and 32.95 mg Al (100 g)-1, respectively). High levels of mobile Al were especially frequent in the forest soils, with 35 (Ah), 85.0 (Eg) and 93.3 % (B 1tg) of the tested samples ranging above 10 mg Al (100 g) -1