Impact of long-term application of blast furnace and steel slags as liming materials on soil fertility, crop yields and plant health (SLAGFERTILISER) : final report

Fertilisers produced from ferrous slags have been used in agriculture since the end of 19th century. The objective of this project is to evaluate the effects of currently produced iron and steel slag (BFS, BOFS and LFS) fertilisers and liming materials on crop yields and quality as well as on selected biological and chemical soil parameters in different soil and climate conditions throughout Europe. Different field trials were carried out in Finland (SSAB), Germany (AGHK) and Austria (AGES) where one new test field in each country was selected and the soil was characterised. In addition 24 lysimeter tests were carried out in Italy (SSUP) with the soil and water mimicking that from around ILVA steel plant which have been characterised. All new test fields and lysimeters were fertilised with BOF slag. This enabled comparison of effects of silicate liming materials under different climatic and soil conditions. AGHK carried out three long-term field experiments with fertilisers and liming materials produced from BF and steel slags. Two of these trials (G2 and G3) are carried out on grassland and one (G4) on arable land. AGES is carrying out two long-term field experiments (A2 and a3) with Thomasphosphate (basic slag). Yields and plant health in most crops fertilised/limed with slag were comparable or better then natural fertilisers. Accumulation of Cr and V was seen in the soil over time, but less in the crops. Liming of forest soil (DH) and trees growth was evaluated after 2.5 years.