Fertilizer, Not Soil, Is Major Source of Toxic Metals in Wheat

Plants absorb nutrients through their roots, but also toxic metals like cadmium.Researchers previously debated whether these metals originated from the soil or applied fertilizers. A team led by the Helmholtz center for Environmental Research (UFZ) and Duke University (USA) investigated wheat grains and,using isotope signatures,discovered that most toxic metals come from mineral fertilizer.

Combining mineral and organic fertilization could lower toxic metal levels and boost essential nutrients in crops. This is the conclusion of the study published in “environment International.”

“Field and greenhouse studies show fertilization type – mineral or organic – impacts metal content in food plants,” says prof. Dr. Marie Muehe, head of the plant biogeochemistry working group at the UFZ and co-study leader. “But we didn’t know if plants absorbed metals from the soil or directly from the fertilizers.” This question drove the German-American research team’s current study.

120 Years of Research in Bad Lauchstädt

The scientists analyzed soil samples and wheat grains from the Static fertilization experiment at the UFZ research station Bad Lauchstädt. Established in 1902, this experiment is a globally significant long-term study due to its duration.

“Some fields haven’t been fertilized in over 120 years, while others receive only mineral fertilizer, organic fertilizer like manure, or a mixture of both,” explains Marie Muehe. Over time,the soil properties have diverged significantly,including pH and organic matter content.This long-term test provided the ideal material for their research.