Recently, Biproduct Recovery received EA approval to apply 10,000 tonnes per year (expected to increase to 30,000 tonnes per year) of cement kiln dust (CKD) to agricultural land as a lime substitute at 3 UK sites. Although both the company and the EA are confident of the environmental safety of this process, never before in the UK (and possibly the world) has such a large scale CKD application been proposed. Overseas research suggests that CKD source substantially changes its chemical composition; thus the availability of 2 different CKDs to Biproduct Recovery (and this project) provides a generic test of the impacts of CKD application. This project represents a novel opportunity for the company to enhance its environmental credentials potentially opening up new markets, and the wider academic community to better understand the long-term impacts of CKD applications on crop nutrient/water relations and soil microbial processes.
We hypothesise that moderate CKD application is an agriculturally sustainable (based on crop, soil and microbiological assessments) soil amendment that can increase soil carbon storage.
We propose glasshouse (mini-lysimeters for detailed assays of crop water and nutrient balance) studies in conjunction with 3 years of in situ measurements on CKD-amended soils with the following aims:
• Can impacts of CKD application on crop production, nutrient status and water use efficiency be explained solely in terms of its soil alkalising properties ?
• Can monitoring soil bioavailable metal concentrations (with DGT) predict crop metal bioaccumulation?
• Do key indicators of soil physical / biological properties change after CKD application and allow C/ N soil sequestration to be predicted ?