Use of green and food derived composts to improve brownfield soils for the purpose of energy crop production
Litterick, A.1 ,Wood, M.1 and Booth, E.2, 1Earthcare Technical Ltd, UK, 2SAC
(free)
Abstract:
This paper summarises the findings from a recently completed WRAP-funded project which aimed to determine whether PAS 100 green or food-derived compost improved the yield and quality of energy crops (miscanthus, reed canary grass and oilseed rape) grown on a recently restored quarry site in Fife. Although miscanthus failed to establish on the site, both oilseed rape and reed canary grass grew and were harvested in 2010, less than 2 years after restoration of the site. Acceptable yields and quality of rape were recorded only where green compost had been incorporated into the seed bed at 90 t/ha in two consecutive Springs prior to harvest. Yields of reed canary grass were significantly higher where either type of compost had been incorporated into the seed bed (at 90 t/year) once, 18 months prior to harvest. The potential for use of PAS 100 composts to improve the quality of soils and soil substitutes on restored Scottish sites for the purposes of energy crop production are discussed.
Key words
Energy crop, green compost, food-derived compost, reed canary grass, miscanthus, oilseed rape
Introduction
There is growing interest in the use of plant-derived feedstock for energy generation. The main drivers for development of alternative energy sources differ between countries, but in most cases, they relate to issues concerning fuel security, the need to increase the use of renewable fuels, fuel costs and the environment. The EU Commission has proposed a mandatory target of 10% of transport fuels to be derived from biofuels by 2020. Recent rising prices for crop commodities have been partly attributed to demand for biofuel, however in reality, a succession of weather events around the world and low commodity stocks have had a larger effect, with biofuel use currently accounting for only a small proportion of demand. Nevertheless the increased profile of biofuels has stimulated a debate on use of land capable of food production being used to produce fuel.
The use of land which is less appropriate for high quality food production e.g. brownfield sites is likely to be considered more acceptable. The cost of fertiliser has increased over the past 2 years, and prices have become very variable, which is leading to uncertainties when predicting the cost-effectiveness of different crops. There is growing interest in using bulky organic materials such as composts, as a means of reducing reliance on synthetic fertilisers and increasing the sustainability of production systems, whilst improving soil quality. This work aimed to assess the potential for using PAS100 food-derived and green composts during production of miscanthus, reed canary grass and oilseed rape on brownfield sites in Scotland through a short literature review and by assessing the performance of the three crops in a small-scale replicated field trial on a brownfield site in Fife. The performance of these crops and their potential for use on brownfield sites are reported in this paper. A detailed account of this work will be published shortly on the WRAP website (www.wrap.org.uk)
