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Estonia considers liming as a result-based agri-environmental measure

One of the objectives of the new Common Agricultural Policy (CAP) is to bolster environmental care and climate action and to contribute to the environmental and climate objectives of the EU. In Estonia, SWOT analysis was prepared, and it showed that increasing soil organic carbon is needed to contribute to the climate change mitigation.

Soil is the largest carbon pool in the terrestrial biosphere and acidity is one of the reasons why soil organic carbon declines. According to Agricultural Research Centre of Estonia, there is a strong correlation between soil acidity and organic carbon. More than 27 000 soil samples from agricultural lands in Estonia have proven that in areas where the soil is acidic, the soil organic carbon content is lower. Consistent agricultural practices through liming could enhance the ability of soils to store carbon. In addition, neutralizing soil acidity and ensuring optimal calcium status improves soil structure, air and water regime. Improved soil structure reduces erosion and compaction. Structural soil creates a more conducive environment for plant roots to develop and beneficial microorganisms to survive, allowing access to water and nutrients from deeper layers.

Considering the above mentioned, stakeholders were asked to take part in a liming workgroup to give an input how liming should be implemented under CAP Strategic Plan. After two days of discussions it was proposed that liming should be implemented as a result-based measure.

In the planned measure commitments should be taken for a five-year period, which ensures flexibility for farmers to lime and reduce the risk that external factors will hinder the achievement of the result. To ensure that liming has been conducted, soil samples taken before the commitment period will be compared to soil samples taken after liming. Lime is typically applied every few years to agricultural soils to keep soil pH at optimum level. Both correction liming and maintenance liming should be supported. Correction liming should be performed if the pH of mineral soils is below 5.5. As liming must be consistent practice, it is necessary to continue with maintenance liming which is recommended do be done once in three years. As the result counts, after liming the pH of the acid soil shall increase. In case of maintenance liming the calcium content must not decrease. 

To avoid CO₂ emissions, primarily the use of ash or a mixture of ash and limestone will be required. The use of ash would allow limiting CO₂ emissions from liming, as it is predominantly calcium oxide, which does not result in additional emissions. It also contribute to the circular economy by helping to use the by-products and reduce the burden on the environment.

Experiences with result-based measures from other countries show that it is important to increase the knowledge. In the planned liming measure training courses play an important role to ensure consistency of liming and climate impact.

With the expert workgroup the first steps are done to build up a result-based liming measure. The next step is to get approval from the European Commission so the measure can be applied in the upcoming CAP period.

Sandra Salom, Ministry of Rural Affairs, Estonia