Sludge-borne salt effects on survival of Bradyrhizobium japonicum
- Univ. Maryland, College Park (United States)
The soil population of Bradyrhizobium japonicum, the microsymbiont of soybean [Glycine max (L.) Merr.], is reduced following land application of sewage sludge. Previous research on the ability of B. japonicum to survive in soil recently amended with sewage sludge has been conflicting as to whether sludge-borne salts or heavy metals inhibit survival. To examine this question, sewage sludge compost was added to a rhizobia-free, Sassafras sandy loam soil amended with various rates of sludge compost, inoculated with B. japonicum USDA 110 ARS and the mixture was incubated for 42 d. The population of B. japonicum was reduced to nearly undetectable levels when inoculated into soil amended with sludge compost at a rate of 25%. The sludge compost was subsequently leached with 3-, 6-, 9- and 12-column void volumes of distilled water resulting in sludge compost samples were added to soil at a rate of 25% and the mixture inoculated with B. japonicum. Soil amended with sludge compost leached with six void volumes water exhibited the highest rhizobial population, while soil amended with unleached sludge compost contained the lowest rhizobial population. In soil amended with sludge compost leached with 3-, 9-, and 12-void volumes water, populations were not significantly different. Results demonstrate that sludge-borne soluble salts, and not heavy metals, are primarily responsible for short-term reductions in bradyrhizobial populations following the application of very high rates of sludge to soil.
- OSTI ID:
- 6994692
- Journal Information:
- Journal of Environmental Quality; (United States), Journal Name: Journal of Environmental Quality; (United States) Vol. 21:2; ISSN JEVQAA; ISSN 0047-2425
- Country of Publication:
- United States
- Language:
- English
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540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
560300 -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
CONTAMINATION
DISSOLUTION
ELEMENTS
FUNGI
GROUND DISPOSAL
LEACHING
MANAGEMENT
MATERIALS
METALS
PLANTS
SALTS
SENSITIVITY
SEPARATION PROCESSES
SEWAGE
SEWAGE SLUDGE
SLUDGES
SOILS
TOXICITY
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES