Metal Amended Liquid Sludge Experiment

  • Experiment Code: W/CS/428
  • Experiment Site: Woburn
  • Objectives: To the effects of zinc, copper and cadmium on soil microbial activity with low organic matter inputs.
  • Description: Enables the comparison of metal concentrations (zinc, copper and cadmium) at 3 rates in small amounts of organic matter applied as a specially made liquid sludge applied. Samples of the sludge used and periodic soil and plant samples are available in the Rothamsted Sample Archive. This experiment is part of a network of 3 sites across the UK and can also be compared with related Contaminated Sludge Cake Experiment and Metal Salts Experiment, also at Woburn.
  • Date Start: 1994
  • Date End: Ongoing

Key Contacts

  • Steve McGrath

  • Role: Principal Investigator
  • Organisation: Rothamsted Research
  • Address: West Common, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom


  • The e-RA database, including the published datasets generated from it, is part of the Rothamsted Long-Term Experiments - National Bioscience Research Infrastructure (RLTE-NBRI) , which also includes the Long-Term Experiments, the Sample Archive and Rothamsted's environmental monitoring activities including the weather stations and its role in the UK Environmental Change Network.
  • The RLTE-NBRI is supported by the Lawes Agricultural Trust and the Biotechnology and Biological Sciences Research Council (Grants BBS/E/C/00005189 (2012-2017); BBS/E/C/000J0300 (2017-2022); BBS/E/RH/23NB0007 (2023-2028)).

Experimental Design


  • Each plot received only one of the three metal amendments for 3 years between 1995 and 1997. In addition to the 9 treated plots there were 2 low metal content only sludge treatment plots and 2 untreated/no sludge control plots. All sludge treatments received the same organic matter loading.


  • Period: 1995 - Now
  • Experiment Design Type: Randomized complete block design
  • Number of Blocks: 3
  • Number of Plots: 39
  • Number of Harvests per Year: 1


Crop Years Grown
Rye Grass


Factors are the interventions or treatments which vary across the experiment.

Zinc Nutrient Exposure

Description: Applied as liquid sludge

Application: Whole Plot

Level Name Amount Years Frequency Crop Method Chemical Form Notes
Rate 1 348 kg/ha 1995 - 1997 annually
Rate 2 696 kg/ha 1995 - 1997 annually
Rate 3 1094 kg/ha 1995 - 1997 annually

Copper Nutrient Exposure

Application: Whole Plot

Level Name Amount Years Frequency Crop Method Chemical Form Notes
Rate 1 181 1995 - 1997 annually
Rate 2 351 kg/ha 1995 - 1997 annually
Rate 3 523 kg/ha 1995 - 1997 annually

Cadmium Exposure

Application: Whole Plot

Level Name Amount Years Frequency Crop Method Chemical Form Notes
Rate 1 5.02 kg/ha 1995 - 1997 annually
Rate 2 7.8 kg/ha 1995 - 1997 annually
Rate 3 10.58 kg/ha 1995 - 1997 annually

Site: Butt Close West - Woburn

  • Experiment Site: Woburn
  • Management: Plots were bounded by wooden boards prevent soil movement during cultivation. Cultivations were carried out annually to ensure that the sludge additions were evenly incorporated in the top 0-25cm. The soil pH was maintained at 6.5.
  • Visit Permitted?: No
  • Elevation: 96 Metres
  • Geolocation:    52.01195, -0.597963


  • Type: Arenosol

Soil Properties

Variable Value Reference Year Is Estimated Is Baseline
Sand content 83% (Percent) 1995 NO YES
Silt content 8% (Percent) 1995 NO YES
Clay content 9% (Percent) 1995 NO YES
Soil pH 7.3 () 1995 NO YES
Soil organic carbon 1.1% (Percent) 1995 NO YES
There are currently no prepared datasets online for this experiment. However, there may still be data available but requiring curation. For more information please contact the e-RA curators.


Creative Commons License These media (images and videos) are available under a Creative Commons Attribution Licence (4.0) with attribution to Rothamsted Research.


Key References

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For further information and assistance, please contact the e-RA curators, Sarah Perryman and Margaret Glendining using the e-RA email address: