ALOWANCE – agricultural landbank software

ADAS developed a management tool to quantify the national capacity of agricultural land to accept organic waste such as farm manures.

Background

Organic materials, like farm manures and composts, are a valuable source of nutrients for crop growth and are often used to enhance soil condition. Potentially, millions of hectares of agricultural land in England and Wales could benefit from organic material recycling. However, not all soil or land use are suitable. Soil type, slope, water course proximity and risk of soil compaction are all factors that have to be considered.

Actions taken

In 2005, Defra commissioned ADAS (Project ES0128) to develop a strategic management tool to quantify the national capacity of agricultural land to accept organic materials such as farm manures, biosolids (sewage sludge), industrial ‘wastes and municipal composts, etc.

To calculate the size and distribution of suitable land, ADAS Digital team developed the Agricultural Land and Organic ‘Waste’: A National Capacity Estimator (ALOWANCE). This GIS-based tool estimates the available agricultural land based on physical and practical constraints, as well as legislative restrictions. These include:

restrictions on nitrogen loading rates within nitrate vulnerable zones
restrictions in the sewage sludge directive (i.e., soil pH and heavy metal concentrations)
topography and proximity to water courses (surface and ground)
risks of pathogen transfer to food crops and water bodies
crop nutrient requirements
land management agreements in environmentally sensitive areas, etc.
restrictions on manure use in sites of special scientific interest, national nature reserves
rules for the management of organically farmed land

Software functionality and uses

ALOWANCE has an embedded methodology for calculating:

the potential landbank capacity
current farm manure nitrogen production
the proportion of the landbank already taken up by farm manures and existing non-farm organic materials (i.e. biosolids, compost, paper crumble, digestate)
the land remaining for ‘new’ sources of organic materials

It can identify areas where there is a shortage or surplus of agricultural land for recycling organic materials.

In conjunction with Grieve Strategic, ADAS has used the ALOWANCE model to enable effective planning of biosolids recycling by water companies since 2007. It has become a key supporting service to their asset management business plans. Output from the model is used for scenario testing to calculate landbank capacity under a range of current, or potential future conditions.