Modern composts for soil health, good crops and landscaping

Scientists in EPI have been awarded more than £200,000 in research grants, 2007-2009, to find and test new uses for urban green wastes in eco-engineering and agriculture.  

People living in towns and cities produce tons of garden waste - grass cuttings, hedge clippings, weeds, dead plants. This 'urban green waste' is a problem to get rid of because little of it can go to landfill sites, it's not much good for anything in its original state and there's too much of it to process locally in compost heaps. Yet urban green waste contains carbon and plant nutrients that are essential for the earth's life-systems. If it could be  processed into something useful, it would help reduce the carbon footprint of towns and cities (greenhouse gas emissions) and if applied to land could greatly reduce problems such as soil erosion and infertility.

What's the problem?

Well-tried commercial operations already exist for composting, but turning one type of waste into another is still no easy task on this scale.  New uses with an almost unlimited capacity have to be found. Even the traditional use of compost to improve the structure of soil and its capacity to hold and release nutrients and water has to be compared against other applied nutrients if it is  to be used in commercial agriculture. There are potential new uses in eco-engineering, combining steel and concrete with soil and plants to make slopes more stable and less prone to failure due to extreme climatic events. Slope-failure is one of the main problems in maintaining the rail network, for example, the cause often being the slow or inadequate growth of vegetation and deep roots in new or re-made embankments and cuttings.  Moreover, the final product (the compost ) must have certain physical, chemical and biological properties fit for purpose, among which it must be safe for humans and the wider environment.  We therefore need to define specifications for each type of compost and come up with certified methods to test its ability to do the job.

What's being done about it?

Scientists in EPI are using basic knowledge in soil biophysics, microbiology, nutrition and plant growth in research projects on the design and suitability of composts and composting methods.  The research is funded mainly by WRAP (Waste and Resource Action Programme) and the Scottish Government. The first experiments began on the SCRI farm in 2005, since when different amounts and types of compost and other manures have been applied to experimental plots and their potential for carbon storage and soil improvement  measured (see photograph to right).  Operations were extended by 2007 to confirm the high utility of the the composts on two commercial farms. New funding from 2009 will allow development and testing of applications in eco-engineering, notably in stabilising slopes.  Dundee City Council not only provide the compost but will maintain a demonstration site  on slope stabilisation. The benefits of this research will be practical and universal.

Further information and contacts

Contacts: Ron Wheatley. In the new work on geotechnical engineering, Ron is joined by Paul Hallett and Blair McKenzie from SCRI and colleagues from the University of Dundee. Funding: mainly from WRAP and the Scottish Government, in excess of £200,000.

WRAP - website of the Waste and Resources Action Programme 

Dundee City Council - Discovery Compost web page

(Article added 3 November 2008)