Microbial biomass dynamics in biosolids amended agricultural soils
Viana F P, Rogers M and Smith S R
Centre for Environmental Control and Waste Management, Department of Civil and Environmental Engineering, Imperial College London
(free)
This work examines the effects of different types of biosolids and livestock manure applications on the microbial population dynamics of agricultural field soil as part of ongoing investigations to quantify the ecological interactions between different groups of soil organisms responsible for the decay of enteric microbes in sludge-amended agricultural soil under temperate conditions. Soil amendments were applied to two contrasting soil types and included four representative types of biosolids used on farmland in the UK (liquid, dewatered and thermally dried digested biosolids and lime-treated cake), cattle and pig slurries, and cattle manure. A control treatment with and without grass, and protozoa inhibition treatments (thiram) were also present. Microbial biomass C was measured using the chloroform fumigation-extraction (CFE) technique, where soil microorganisms are degraded with chloroform and the cytoplasm contents transformed into extractable components. Soil physico-chemical properties had a major influence on soil microbial biomass dynamics and, in particular, larger background biomass concentrations were measured in soil containing the most organic matter. Microbial biomass dynamics in amended soil were determined by: (1) the microbiological content and (2) substrate availability of the supplied materials.
KEY WORDS
Agriculture, Biosolids, Microbial biomass, Recycling, Sewage sludge, Soil
