Bőrgyári szennyvíziszap-terhelés hatása a tavaszi árpa B, Ba, Ni, Co, Cu elemeinek forgalmára tenyészedény-kísérletben | The effect of leather factory wastewater sludge load on the B, Ba, Ni, Co and Cu cycle in spring barley in a pot experiment

Summary In the third year of our pot experiment, we examined the effect of leather factory wastewater sludge load on the mineral composition of spring barley and change of experimental soils’ (acidic and calcareous sandy soil; acidic and calcareous heavy soil) “total” B, Ba, Ni, Co and Cu content estimated by HNO ₃+cc. H ₂O ₂ exploration, as well as the NH ₄-acetate+EDTA-soluble content of the same elements. We applied 0; 7.5; 15; 30 and 60 g kg –¹ sludge loads calculated for air-dry weight. The maximum 60 g kg –¹ load would mean to plough 180 t ha –¹ air dry matter into the soil, thereby representing 6% weight ratio in the ploughed layer. Yearly pot number was 80 (5 sludge doses × 4 soils = 20 treatments × 4 replications = 80 pots). The pots were 10 l plastic buckets with holes in their bottoms. Main conclusions: 1. The soils’ original “total” B, Ba, Ni, Co, Cu, Pb and As content estimated by cc. HNO ₃+cc. H ₂O ₂ exploration and the NH ₄-acetate+EDTA-soluble content of Ba, Ni, Co, Cu and Pb further increased as the plasticity of soils improved. Nearly 80% of B, 40% of Ba and Pb and 20–25% of As transferred into the soil by sludge was accumulated in NH ₄-acetate+EDTA-soluble form in the average of soils. As a result of low Cu load, the “total” and soluble Cu content of soils did not considerably change, whereas the Ni and Co content became diluted. 2. As a result of sludge application, the B content of the yield of spring barley grain and straw increased, whereas the respective Co, Cu, Pb and As concentrations did not change considerably. Nevertheless, the quantity of Ba and Ni decreased in the plant organs. B and Ba became enriched mainly in the straw, exceeding their concentration in grains by a magnitude. Even Co can be found in a four times higher quantity in the associated yield than it is in the grain. As for their concentration, Cu and Ni are distributed in a more or less steady proportion in the grain and the straw. 3. Spring barley did not become contaminated by the examined microelements, they remained suitable for human and animal consumption on the basis of its composition. The grain and straw yield of crops increased 3–3.5 times their previous values, the sludge load did not cause depression.