AHDB Environmental and Agricultural Resource Efficiency Tool (EAgRET)

Abstract

The aim of this project was to develop a resource use efficiency calculator to build awareness of how farm management decisions on the use of resources affects the environmental and economic performance of farm businesses. The tool needed to be user-friendly and had to have the ability to be used by the AHDB team in their interactions with UK farming and supply chain businesses to investigate scenarios of potential changes in farming systems and determine the environmental and economic impacts of these scenarios.

The AHDB Environmental and Agricultural Resource Efficiency Tool (EAgRET) is the resulting outcome from this project. We believe that this is the first tool of its kind that is able to produce a suite of metrics for assessment of resource use and efficiency at multiple summary levels (Farm Business, Farm Enterprise, Farm Activity and Product). EAgRET has been designed primarily for the assessment of the relative impacts of different scenarios on the resource use and environmental impact of farm businesses. The primary design, and hence use, focus of EAgRET is to examine the direction of change of emissions of a farm business over a period of time or to examine the potential impact of different management scenarios for a farm business. Whilst EAgRET can be used to provide “one-off” assessments of a farm business, this is not what it was designed for and use in this way could provide a misleading assessment of emissions from a farm business.

The tool uses a hierarchical structure to define farm businesses, consisting of farm business, farm enterprise and farm activities, where a farm activity is considered to be the lowest unit at which a farm is managed (e.g. a crop within an arable system or a herd type within a livestock system). This hierarchical structure means that EAgRET is able to represent a wide range of farm business structures and allows EAgRET to define and assess the impacts of transfer of resources between farm activities within a farm business. EAgRET contains a library of default farm activities, farm enterprise and farm business that can be used as the starting point for the development of scenarios of agricultural change or farm business structure change. The default data represents the average UK case for a number of crop and livestock systems.

EAgRET uses current best practice for calculation of metrics, with IPCC Tier 1 and Tier 2 calculations used for greenhouse gas emissions, the Defra/ADAS soil surface nutrient balance methodology used to provide nutrient balances, and life cycle analysis methodology and emission factors used to represent other key environmental impacts. EAgRET splits emissions into three categories: embedded emissions from purchased resources, embedded emissions from transferred resources and emissions resulting from farm management processes. This allows greater interpretation of the results, particularly in relation to determining which components of the farm business have the greatest impact on the overall emissions. EAgRET is the first tool that we are aware of that provides this split in the emissions. EAgRET uses an economic basis for assigning metrics to products (and for calculating emissions associated with transferred resources). This is the most common methodology used for assignment of metrics.

EAgRET is a powerful tool for assessment of the environmental impacts for scenarios of changes in agricultural farm businesses. Four example case studies were developed to show how EAgRET can be used to identify the potential impacts of changes to a number of agricultural systems. The case studies developed for the project were:

• Transfer of ware potato waste to alternative use (anaerobic digestion or animal feed)
• Transfer of straw and manures between livestock and arable farm enterprises
• Use of sexed semen in dairy production
• Protein content in diet and use of home-grown protein versus imported protein

The results from these case studies confirmed that there are likely to be some environmental gains from greater integration of crop, livestock and renewable energy (AD) enterprises, through greater displacement of bought in feeds, fertiliser and grid electricity. The results also illustrated that more efficient use of resources through effective transfers may not always produce gains across all environmental measures and that the most environmentally beneficial resources transfers may not always deliver the best financial returns. Therefore trade-offs will need to be made between economic and individual environmental impacts in selecting appropriate strategies for greater resource use efficiency and integration within agricultural systems.

It is important to note that part of using EAgRET requires a consideration of the question that needs to be answered and the development of appropriate baselines to allow the relative impacts to be determined.