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Long-term sludge experiments: Additional soil organic carbon analyses - SP0131

Description
The objective of the study is to measure organic carbon (C) concentrations in the soil samples taken in spring 1999 and to use these data to further evaluate relationships between soil heavy metal concentrations and soil microbial activity.
At seven sites with contrasting clay contents throughout England and Wales, selected metal rich sludge cakes were applied between 1994 and 1997 (Phase I) to establish zinc, copper and cadmium metal dose-response curves. During phase II of the project (SP0125) effects of the established soil metal concentrations on selected soil microbial (biomass, respiration, rhizobia and Biolog®), chemical (total and extractable metals, speciation of metals, organic carbon, cation exchange capacity and soil pH) and physical properties (bulk density) are being measured.
Metal-amended liquid sludges were also applied at three sites in England during phase I of the project to establish zinc, copper and cadmium metal dose-response curves, and to provide a contrast in likely metal availability to the sludge cake additions.
Preliminary relationships have been established between soil metal concentrations and soil microbial properties measured on the spring 1999 soil samples, but using soil organic C data from 1997. To further evaluate the relationships between soil metal concentrations and soil microbial properties, we propose to analyse the same soil samples taken in 1999 for organic C concentrations.
The work addresses DEFRA’s policy objectives of providing a sound scientific base for the continued development of policies on soil protection where sewage sludge is being applied to agricultural land, by evaluating the effects of heavy metals additions in sewage sludge on soil fertility (microbial, chemical and physical properties) and agricultural productivity.
Objective
The overall objective of this study is to further evaluate relationships between soil metal concentrations and soil microbial activity on the spring 1999 soil samples.

In more detail, the specific objectives of the project are:

1. To measure organic carbon concentrations in the soil samples taken in 1999 as part of the main project (SP0125).

2. To use the organic carbon measurements to further evaluate relationships between soil metal concentrations and soil microbial activity.
Project Documents
• Final Report : Long-term sludge experiments: Additional soil organic carbon analyses   (161k)
Time-Scale and Cost
From: 2001

To: 2002

Cost: £6,920
Contractor / Funded Organisations
ADAS UK Ltd.
Keywords
Environmental Protection              
Heavy Metals              
Organic Carbon              
Sewage Sludge              
Sewage Treatment and Disposal              
Soil              
Waste Management              
Fields of Study
Soil Protection