Comparison of growth characteristics for waste-derived composts

The EU Landfill Directive has set targets for the reduction of biodegradable municipal solid waste sent to landfill. This means that by 2020 the UK will only be able to landfill 35 % of the amount of biodegradable waste that was landfilled in 1995. This has created a significant demand for technologies both to reduce and reuse the diverted wastes, of which composting is one such technology. In Wales, unlike England, there are prescribed targets for composting. For example, by 2010 its will be necessary to compost at least 328,000 tonnes of biodegradable material, a threefold increase on current practice. Developing markets for the composted products is a key issue and is dependent on establishing consumer confidence. To this end the UK Composting Association is promoting standards (BSI, PAS-100) for such products that involve growth related parameters. This paper presents the results of growth trials using two commercially available multipurpose composts, four products of waste-derived composting and one vermicompost. Replicated growth trials using each compost were undertaken with coriander and tomato in climate-controlled chambers. Germination rates and growth parameters after two weeks are reported alongside compost nutrients status (N, P, K and Ca) before and after plant growth. In certain cases it is demonstrated that waste-derived products compare favourably with those available commercially.