engleski

Impacts of ameliorative phosphorus fertilization on mobile cadmium status in soil

The harmful elements monitoring, particularly cadmium (Cd), have become important for environmental protection. Cd toxicity is mainly induced by mimicking of zinc (Zn) in uptake and metabolism. As in some cases application of phosphorus (P) fertilizers are responsible for soil contamination with Cd, aim of this study was testing status of mobile fraction of Cd in soils following ameliorative P (PK) fertilization. Three stationary field experiments with increased rates of P (PK) application (monoammonium phosphate or MAP: 12% N + 52% P2O5, KCl containing 60% K2O, NPK 7:20:30) have been conducted in April of 2003 under conditions of continental Croatia at localities as follows: Okucani (the exp. I), Korenicani (the exp. II) and Maslenjaca (the exp. III). The experiments have been conducted by randomized block design in four replicates (basic plot, depending on the experiment, from 77.0 to 92.4 m2 ). The fertilizers were added on the usual fertilization (the control) and different amounts of nitrogen (N) added by MAP were equalized by CAN (calcium ammonium nitrate: 27% N + 2-3% MgO). For the next years only usual fertilization of the experiments were used. The fertilization treatments were as follows: control, 500, 1000 and 1500 kg P2O5/ha (the exp. I) ; control, 1250, 2500 and 3750 NPK/ha (the exp. II) ; control, P2O5 kg/ha = 250, 500, and 750, 500 kg K2O/ha, both 500 P2O5 and K2O kg/ ha (the exp. III). Soil sampling to 30 cm of depth was made by auger from each basic plot in October of 2005. Mobile Cd was extracted with NH4 Acetate + EDTA (pH 4.65) and its concentrations were determined using inductively coupled plasma (ICP). In general, amounts of Cd in soils were low (means 0.138, 0.082 and 0.131 mg Cd/kg, for the exp. I, II and III, respectively) and differences in soil Cd status among different fertilization treatments were non-significant (mg Cd/kg in the ranges from 0.132 to 0.140, from 0.077 to 0.091 and from 0.117 to 0.140, for I, II, and III, respectively).

cadmium in soil ; phosphorus fertilization ; NH4 Acetate - EDTA extraction

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