Assessment of Nitrate Accounting Tools For the Poole Harbour Nutrient Management Scheme

The National Farmers Union (NFU) are establishing a farmer-led solution to mitigate high nitrate emissions from agriculture into Poole Harbour. Poole Harbour is of international importance for its wildlife however high nitrate levels are damaging valuable habitats. There are many approaches that can be used to help reduce nitrate loses and one which has proved successful is the use of nutrient budgeting also known as nutrient accounting. This technique compares the quantities of nutrients entering the farm with that within the farm outputs to provide an assessment of likely environmental losses. This approach can provide an early indication of potential problems arising from a nutrient surplus or deficit and can help farmers to better understand the factors influencing the farm nutrient status. Whilst very simple estimates can be done without sophisticated software this approach tends not to be sufficiently accurate nor responsive to changes in practices and so generally a software tool is needed. Over the last couple of decades a variety of nutrient accounting tools have been developed each with its own characteristics, strengths and weaknesses. Consequently, the National Farmers Union (NFU) require the service of a consultant to evaluate nutrient accounting tools that could accurately capture the amount of nitrate leaching from agricultural land entering the Poole Harbour Catchment to identify those that best meet a predefined specification. This document is in response to an Invitation to Tender sent to us, the Agriculture and Environment Research Unit (AERU), University of Hertfordshire, on 20th January 2021.