Ipari-kommunális szennyvíziszap-terhelés hatásának vizsgálata tenyészedény- kísérletben

Translated title of the contribution: Effect of industrial-municipal sewage sludge loads in pot experiments

Imre Kádár, Balázs Morvai

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Pot experiments were set up to investigate the effect of industrial-municipal sewage sludge application on the mineral composition of spring barley and on changes in the "total" (after digestion with cc. HNO3+cc. H2O2) and NH4-acetate+EDTA- soluble element fractions in the experimental soils (acidic and calcareous sand, acidic clay loam and calcareous loam). Rates of 0, 2.5, 5, 10 and 20 g sludge/kg soil (in terms of air-dry mass) were applied to each soil. In the field, the maximum 20 g sludge/kg soil would represent the ploughing in of 60 t/ha air-dry matter, i.e. a mass ratio of approx. 2%. The 5 sludge application ratesx4 soils = 20 treatments were carried out in 4 replications, giving a total of 80 pots (10-litre plastic buckets with perforated bottoms). The following conclusions could be drawn from the results: - Although the maximum sludge rates resulted in the application of 10-14 times the permitted annual quantities of Zn, Cu, Cr and Cd over a period of three years, no yield depression was observed: the mean grain yield of spring barley was five times that of the control treatment and the straw yield 3.5 times greater in the third year. - The "total" Zn, Cu, Cr and Cd contents estimated after digestion with cc. HNO3+cc. H2O2, the method routinely used in Hungary, are not suitable for measuring soil contamination, as some 40% of the contaminants were not detected with this method, i.e. only around 60% of the elements applied could be retrieved. Less than 1% of the Cr introduced into the soil could be detected in the NH4-acetate+EDTA-soluble fraction, compared with almost 35% for Zn, Cu and Cd. - The soil contamination limit values valid in Hungary appear to be unjustifiably strict and inflexible, as they do not take into account soil properties (pH, texture, etc.) that influence nutrient uptake. On the clay loam soil from Gyöngyös the Cr and Cd concentrations in the plants remained low, exhibiting practically no change, in 1999, despite the fact that the limit values for Zn, Cr and Cd in the soil were exceeded. Table 1. Permitted contamination limit values for the placement of sewage sludge on arable land, based on government regulations. (1) Element symbol. (2) In the sludge, mg/kg dry matter. (3) Permitted quantity, kg/ha/year. (4) Maximum value permitted in the soil, mg/kg dry matter. (5) Non-contaminated soil, mg/kg dry matter. Note: Based on the "A" values given in a ministerial decree. Table 2. Major properties of the soils used in the pot experiment when the experiment was set up in 1999. (1) Properties. a) Cation adsorption (T value); b) Clay content (<0.002 mm, %); c) Silt content (<0.02 mm, %); d) Soil plasticity according to Arany (KA); e) Humus %. (2) Brown forest soil with thin interstratified layers of colloid and sesquioxide accumulation, acidic sand (Nyírlugos). (3) Calcareous sandy soil (Orbottyán). (4) Calcareous chernozem, loam soil (Nagyhörcsök). (5) Brown forest soil, acidic clay loam (Gyöngyös). Table 3. "Total" cc. HNO3+cc. H 2O2-soluble element content of the experimental soils at the start of the experiment in 1999. (1) Element symbol, units. (2)-(5): see Table 2. Note: Hg, Mo and Se were below the 0.1 mg/kg detection limit. Table 4. NH4-acetate+EDTA-soluble element content of the experimental soils at the start of the experiment in 1999. (1) Element symbol, units. (2)-(5): see Table 2. Note: Hg and Se were below the detection limit. Table 5. Mean composition of the industrial-municipal sewage sludge applied in the experiment (dry matter basis) and estimated quantity of elements introduced into the soil each year as the result of sludge application. (1) Element symbol, units. (2) Sludge dry matter composition. (3) Sludge loads, t dry matter/ha/year. A. Element loads, calculated as kg/ha. B. Element loads, calculated as g/ha. Note: * 1 mg/kg is equivalent to approx. 3 kg/ha in the ploughed layer. ** pH = 6.1; ash: 45%; organic matter: 35%; C/N ratio: 7-8; NH 4-N: 113 mg/kg; NO3-N: 374 mg/kg. Table 6. Effect of industrial-municipal sewage sludge loads on the air-dry yield of spring barley. (1) Site of origin of soils. a) Mean. (2) Sludge application level, g dry matter/kg soil/year. (3) LSD5%. (4) Mean. A. Grain yield, g/pot. B. Straw yield, g/pot. Table 7. Effect of industrial-municipal sewage sludge loads on the Zn content of the soil and of spring barley on 15 July 1999. (1)-(4): see Table 5. A. Zn load, mg/kg soil. B. "Total" (cc. HNO3+cc. H2O2-soluble) Zn content of the soil, mg/kg. C. NH 4-acetate+EDTA-soluble Zn content of the soil, mg/kg. D. Zn content of spring barley straw+husks, mg/kg. E. Zn content of spring barley grain, mg/kg. Table 8. Effect of industrial-municipal sewage sludge loads on the Cu content of the soil and of spring barley on 15 July 1999. (1)-(4): see Table 5. A. Cu load, mg/kg soil. B. "Total" (cc. HNO3+cc. H 2O2-soluble) Cu content of the soil, mg/kg. C. NH 4-acetate+EDTA-soluble Cu content of the soil, mg/kg. D. Cu content of spring barley straw+husks, mg/kg. E. Cu content of spring barley grain, mg/kg. Table 9. Effect of industrial-municipal sewage sludge loads on the Cr content of the soil and of spring barley on 15 July 1999. (1)-(4): see Table 5. A. Cr load, mg/kg soil. B. "Total" (cc. HNO3+cc. H 2O2-soluble) Cr content of the soil, mg/kg. C. NH 4-acetate+EDTA-soluble Cr content of the soil, mg/kg. D. Cr content of spring barley straw+husks, mg/kg. E. Cr content of spring barley grain, mg/kg. Table 10. Effect of industrial-municipal sewage sludge loads on the Cr content of the soil and of spring barley on 15 July 1999. (1)-(4): see Table 5. A. Cr load, mg/kg soil. B. "Total" (cc. HNO3+cc. H 2O2-soluble) Cr content of the soil, mg/kg. C. NH 4-acetate+EDTA-soluble Cr content of the soil, mg/kg. D. Cr content of spring barley straw+husks, mg/kg. E. Cr content of spring barley grain, mg/kg.

Translated title of the contributionEffect of industrial-municipal sewage sludge loads in pot experiments
Original languageHungarian
Pages (from-to)333-352
Number of pages20
JournalAgrokemia es Talajtan
Volume56
Issue number2
DOIs
Publication statusPublished - Dec 1 2007

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Soil Science

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