Data from: Long-term fertilization impacts on metal(loid) transfer from soil to wheat in a 120-year fertilization experiment - using 87Sr/86Sr isotopes as metal(loid) tracer

Mineral and organic fertilizers are widely used to sustain food production but can also contribute toxic metal(loid)s to agricultural systems. However, their long-term impacts on metal(loid) accumulation in soil and crops remain insufficiently explored. This study uses a unique 120-year field experiment to demonstrate that organic (manure), mineral (NPK), and combined mineral+organic fertilization increased total soil concentrations of Zn, Cd, Pb, As, and U. For the first time, we use the 87Sr/86Sr isotopic fingerprint to trace metal(loid) transfer from fertilizer to soil into wheat grains. Metal(loid) concentrations in wheat grains were primarily governed by fertilization-induced changes in soil geochemistry affecting their mobility in soil. For example, mineral fertilization lowered soil pH, mobilizing cationic Cd and increasing its accumulation in wheat grains by 70%. Organic fertilization raised soil pH and organic matter, reducing Cd concentrations in wheat grain to below unfertilized ones. The 87Sr/86Sr in wheat grains matched that of triple superphosphate, which is one of the fertilizers used in mineral fertilization, indicating that wheat Sr and co-occurring Cd were primarily derived from the phosphate fertilizer. In contrast, the behavior of the oxyanion As was distinct, with concentrations in grain increasing by 70% under mineral+organic compared to mineral fertilization alone. Changes in As mobility in both mineral treatments significantly correlated with 87Sr/86Sr. Overall, this study demonstrates long-term metal(loid) enrichment in soil and wheat from mineral fertilization and establishes 87Sr/86Sr as a robust tracer of fertilizer impacts. These findings underscore the need for targeted fertilization strategies to reduce contaminant accumulation in agroecosystems.