Evaluation of the effect on carbon storage in arable land

• environmental compensation for reduced nitrogen leakage (crop cultivation and spring processing);
• environmental compensation for grass growing;
• environmental compensation for protection and adapted protection zones;
• compensation for conversion to organic production.

Carbon sequestration is one of the most cost-effective measures to reduce carbon dioxide in the atmosphere. Agriculture has several management measures that contribute to carbon sequestration in arable land, some of which have been supported by the RDP. This report presents an evaluation of the impact on carbon sequestration in Swedish arable land from the following measures under the 2014-2022 RDP:

• agri-environmental payment for reduced nitrogen leakage (catch crops and spring tillage);
• agri-environmental payment for ley cultivation;
• agri-environmental payment for buffer strips and adapted buffer zones;
• payment for conversion to organic production;
• payment for maintaining organic production.

Factors that may affect the amount of soil carbon in Swedish arable land include the effects of the measures, the extent of the support, levels of soil coal and farmers’ choices.

The analysis is based on four sub-questions, plus one summative, each of which aims to create calculations and estimates that can be used to answer them. The following sub-questions have been developed to facilitate the analysis:

1. What measures under the RDP have an impact on the soil carbon stock in arable land and what is the impact of each measure? What other measures not included in the RDP affect the soil carbon stock?
2. To what extent have farmers applied for the targeted support and how has the scope varied over time and geographically?
3. Has the soil carbon stock in Swedish arable land changed during this period?
4. What other factors impact the implementation of the measures and how much of the measures would have been implemented even without RDP support?
5. Based on sub-questions 1-4, what effect have the measures had on the soil carbon stock in arable land?

The Swedish Board of Agriculture has identified the financial support being evaluated, which is deemed to have a direct impact on soil carbon stock. In addition, the evaluation identifies opportunities for improvement in monitoring data from Swedish arable land to facilitate future evaluations.

The first sub-question is answered through a literature review to compile the measures affecting the topsoil carbon stock and the effect of the measures on coal storage (kg of carbon per hectare per year).

The second sub-question is answered by using statistics from the Swedish Board of Agriculture’s databases to map the change, as well as previous follow-ups and evaluations of specific measures and the RDP.

To answer the third sub-question, the value of the total soil carbon storage (kg carbon per year) in Swedish arable land has been calculated based on existing data and literature.

For the sub-question of what proportion of the measures would have been implemented even without the support or the extent to which the measures depend on the RDP support, semi-structured interviews have been carried out, as well as an orientation literature search. Eight semi-structured interviews were conducted (one of which was answered by email), divided into four representatives of the Swedish Board of Agriculture, three action coordinators (within the Leva project) and one plant cultivation advisor. Action coordinators were chosen based on their knowledge and experience of the incentives that have an impact on farmers’ will to implement environmental improvement measures. An interview question template was used, and based on the respondents’ answers, they were then asked in-depth follow-up questions. The selection of operators was developed together with the Swedish Board of Agriculture.

The results from the various sub-questions have been combined to calculate the support's impact on the soil carbon stock in Swedish arable land.

In terms of limitations, the evaluation is based on previously published studies on the effects of measures on soil carbon sequestration, existing data, and follow-up of the measures’ trends. In addition to compiling trends, no direct analysis of collected data from monitoring programmes has been carried out, and no new collection of soil carbon data has been undertaken for the study.

The evaluation concludes that the cultivation of catch crops, the setting up of buffer strips/buffer zones, and ley cultivation have a positive but small effect on carbon sequestration in arable soils. Farms with beef and dairy animals show a significantly higher carbon stock than crop and pig farms, which could be mainly due to a larger production of ley for fodder.

In addition, RDP support is important for implementing measures to increase carbon storage. The area receiving support is small in relation to the total arable land. If the support is assumed to have full additionality, it could contribute about 20% of the annual change in the soil carbon stock.

New groups of farmers have applied for support and the area has increased. There are, however, large variations between farms with a similar focus, and since the farmers' focus and approach are not shown in the statistics, it is also not possible to calculate the effect of these measures effect on soil carbon stock more precisely.

Management measures that could not be supported also have a positive impact. However organic-related measures seem to have a negative impact.