The need for and the potential of phosphorus recycling in crop production

Phosphorus is not only one of the most important nutrients required by crops but also one of the largest causes of nutrient loads in agriculture. Questions of the use and availability of nutrients are also firmly linked to the security of supply in food production and Finland’s self-sufficiency in nutrients.

A high phosphorus content in arable land increases the water pollution risk which is why the aim has been to lower high phosphorus values by imposing fertilisation restrictions. While there is now a smaller area of arable land with a high phosphorus content, phosphorus recycling is still struggling.

In Finland, crops require roughly 23.3 million kilograms of phosphorus fertilisers per year. This amount could almost exclusively be covered by phosphorus obtained from livestock manure and the side streams of communities and the food industry. Still, almost 12 million kilograms of mineral phosphorus fertilisers are sold in Finland each year.

There is significant regional variation in the supply of recycled phosphorus and the need for phosphorus fertilisers. Cooperation between livestock and crop production farms should be increased to improve the effective use of manure nutrients. In addition, transferring excess phosphorus from one region to the next requires that manure and other nutrient-rich side streams are processed into concentrated recycled fertiliser products. However, significant investments are required to start production. The production and use of recycled fertiliser products can be supported using long-term incentives and straightforward legal provisions.

The phosphorus decree under the fertiliser act entered into force in 2023. It includes several provisions based on our research, including phosphorus fertilisation limits for most crops in different conditions and the usability of recycled fertilisers and the phosphorus contained by manure. We have closely participated in the preparation of the quality decree under the fertiliser act, produced information to support nutrient cycle subsidies under the Ministry of Agriculture and Forestry, and prepared an indicator for monitoring the progress of nutrient recycling.