CN code 310590 covers other mineral or chemical fertilisers containing two or three nutrients (N, P, K) not included in more specific subheadings of heading 3105. This is a residual subheading covering PK (phosphorus-potassium) fertilisers and other compound formulations not classified under codes 310510 to 310560. PK fertilisers are used in agriculture on soils well supplied with nitrogen or in combination with separate nitrogen fertilisation. Classification requires identification of nutrients and their percentage content. Correct classification is essential during customs clearance.

Fertilisers under code 310590 are subject to Regulation (EU) 2019/1009. PK fertilisers (without nitrogen) are not subject to CBAM, while compound fertilisers containing nitrogen under heading 3105 are subject to this mechanism. Cadmium limits in the phosphorus component must be met. Fertilisers are subject to REACH. Transport is not subject to ADR under standard conditions. A Safety Data Sheet is required. Importers must individually assess whether their fertiliser is subject to CBAM depending on nitrogen content.

Import of fertilisers under CN code 310590 requires a commercial invoice with fertiliser composition and certificate of analysis. Importers should check current duty rates in TARIC. Due to the residual nature of the code, customs authorities may closely examine classification correctness. Proof of origin documentation enables tariff preferences. Export from the EU is not subject to restrictions. Importers should hold Binding Tariff Information (BTI) for non-standard fertiliser formulations.

Importing fertilisers under CN code 3105 90 (Other compound fertilisers) is subject to EU Regulation 2019/1009 on fertilising products. Fertilisers must meet quality standards regarding nutrient content, heavy metals (Cd, Pb, Hg), and contaminants. Labels must include an EU declaration of conformity, composition, and application instructions. Transport of high-nitrogen fertilisers falls under ADR (class 5.1). Import from third countries may require a phytosanitary certificate. Market surveillance authorities verify declared parameters against the label.