Microbial activity of Cu contaminated soils and effect of lime and compost on soil resiliency

• Published in: Compost science & utilization Vol. 9; no. 4; pp. 336 - 351
• Main Authors: Kostov, Ognian, Cleemput, Oswald van
• Format: Journal Article
• Language: English
• Published: Emmaus,PA Taylor & Francis 01.09.2001; JG Press; Taylor & Francis Ltd
• Subjects: Agronomy. Soil science and plant productions; application rate; bacteria; Biological and medical sciences; branches; carbon dioxide; composts; copper; Fundamental and applied biological sciences. Psychology; fungi; fungicides; General agronomy. Plant production; microbial activity; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; polluted soils; sandy loam soils; sandy soils; Soil and water pollution; soil fertility; soil microorganisms; soil respiration; Soil science; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Streptomycetes; toxicity; vines; vineyards; Microbial activity; Toxicity; Carbon dioxide; Stimulation; Decomposition; Sandy soil; Soil pollution; Inorganic compound; Actinomycetales; Fungi; Liming amendment; Copper Sulfates; Decontamination; Bacteria; Sandy loam soil; Thallophyta; Compost; Streptomycetaceae; Ecotoxicology; Mineral amendment; Pesticides; Biological indicator; Microbial biomass; Fungicide; Resilience; Concentration effect; Actinomycetes; Respiration; Organic amendment; Chemical contamination
• ISSN: 1065-657X; 2326-2397
• DOI: 10.1080/1065657X.2001.10702052

In vineyards, the long-term use of copper fungicides has increased soil Cu concentrations that can adversely affect the number and activities of soil microorganisms. To better understand this phenomenon and to ameliorate such harmful effects, an incubation experiment was carried out with a sandy loam and a sandy soil to which increasing rates of CuS04 were added. By this treatment, the basal soil respiration (7-55%) and decomposition of added vine branches (46-86%) was inhibited. At the application rate of 500 mg Cu kg-1, soil microbial biomass-C was inhibited (7-66%) in the sandy soil and stimulated (2-10%) in the sandy loam soil. The specific respiration rate was a reliable indicator for Cu stress, and it increased with time and higher Cu concentrations before lime and compost applications. Total number of bacteria and streptomycetes were also strongly inhibited. Fungal population was significantly more tolerant to copper toxicity than the bacteria. A stimulation of fungal population at a dose of 500 mg Cu kg-1 in both soils was observed. A criterion such as "stimulation" lasting for more than 60 days can also be used as indication of Cu contamination of soils. The order of inhibition (on day 125) at a dose of 500 mg Cu kg-1 soil was as follows: A. sandy loam soil (pH> 7.0) - fungi < biomass-C < basal soil respiration < bacteria < streptomycetes; B. sandy soil (pH< 6.0) - fungi < basal soil respiration < biomass-C < bacteria < streptomycetes. The application of lime increased soil recovering ability at a moderate rate (for CO2 production - 22-70% and for biomass-C- 39-156%), but the combination of lime and compost significantly increased soil resiliency (for CO2 production- 16-518% and for biomass-C- 103-693%). The soil resiliency assessed by number of bacteria in compost treatments was 30-120% in sandy loam soil and 92-700% in the sandy soil. Compost and lime application increased the number of streptomycetes from 52 to 500% in sandy loam soil and from 100 to 700% in sandy loam soil. Fungal population was less increased in sandy soil as compared to sandy loam soil. The ecological dose higher than 5% inhibition of microbial processes and microorganisms appears to be suitable to assess Cu contamination of soils. CO2 production, biomass-C and specific respiration rate were less sensitive indicators as compared to streptomycetes and bacteria. It appears that compost application effectively promoted the recovery of soil microbial activity and soil fertility of Cu contaminated soils.