ADAS, together with North Wyke Research and Imperial College, were commissioned by Defra and WRAP to develop a strategic management tool for identifying areas of England and Wales where there was pressure on the agricultural landbank for recycling ‘new sources’ of organic materials.
Around 90 million tonnes of livestock manures, 3-4 million tonnes of biosolids and over 1 million tonnes of compost are currently recycled to agricultural land in the UK annually, with the quantities of compost and digestate predicted to increase as organic materials are diverted away from landfill. Whilst organic materials provide a valuable source of crop available nutrients and can also benefit soil physical properties, there are physical, practical and legislative reasons why not all soils or land uses can receive them.
ALOWANCE (Agricultural Land and Organic ‘Waste’ - A National Capacity Estimator) is a GIS based tool which allows users to calculate the agricultural landbank within a specified distance of a chosen location. Based on nitrogen (N) loadings from livestock manures, biosolids, compost, paper crumble and digestate, ALOWANCE takes into account the following restrictions on spreading:
• Maximum livestock manure N loading rates within Nitrate Vulnerable Zones;
• Sewage Sludge Directive limits on soil pH and heavy metal concentrations;
• Topography and proximity to water bodies;
• Pathogen transfer risks;
• Crop nitrogen requirement;
• Land management agreements in Environmentally Sensitive Areas etc.;
• Restrictions on manure use in Sites of Special Scientific Interest and National Nature Reserves;
• Rules for the management of organically farmed land.
Two versions of ALOWANCE were developed. Web-based ALOWANCE-ONLINE includes pre-selected map layers and a sophisticated landbank calculator tool, whilst ALOWANCE-PLUS provides enhanced functionality and scenario testing capabilities. Taking into account landbank restrictions and current sources of livestock manures and non-farm organic materials, ALOWANCE estimated that 5.1 million hectares were available for ‘new sources’ of organic materials. Spatial outputs, however, showed that in some regions the landbank was already under pressure, suggesting that in future organic materials may need to be transported out of these areas.
ALOWANCE-ONLINE can be accessed at:
http://web1.adas.co.uk/alowancehome/ or http://www.wrap.org.uk/composting/useful_tools.html
For further information please contact Fiona Nicholson on 01756 797130 or email fiona.nicholson@adas.co.uk
