A synthesis of evidence on the implications of applying lime on agricultural soils in a Scottish context

The application of liming products to raise the soil pH in acidic soil conditions has been practised for thousands of years to maintain or improve yield, as crops respond with increased growth to an optimum soil pH. However, there is a cost for the application of liming products with the emission of carbon dioxide (CO₂). Previous research on the effects of soil pH has shown that an optimum soil pH allows the most efficient use of applied fertilisers, which helps prevent costly losses of fertiliser from the system through various forms of pollution (leached from the soil or into water sources or lost via gaseous emissions).

This report covers three specific objectives:

1. Synthesise current scientific understanding of liming, effects on yield, fertiliser efficiency, greenhouse gas emissions and carbon sequestration to describe

· Environmental and yield/economic implications of liming on Scottish farms.

· Greenhouse gas (GHG) emissions and GHG mitigation potential associated with liming.

· Considering the variability of liming outcomes across Scottish farms.

2. Describe the circumstances under which liming is and is not appropriate in a Scottish context.

3. Identify where additional policy and/or behaviour change is required to realise the mitigation potential of liming.