This research project evaluates how long-term manure application on dairy farms influences the buildup of potentially toxic trace metals in soil, crops, water, and manure itself. By comparing fields with decades of manure use to those without manure and to undisturbed land, the study establishes a baseline understanding of metals such as zinc, copper, cadmium, arsenic, and lead. These elements can accumulate over time because they do not break down, and some—like cadmium—can move into crops more readily, posing risks to soil health, plant productivity, and the broader agricultural system.

For dairy farmers, the key outcome is practical, science-based insight into how manure management may affect long-term soil sustainability and farm productivity. The baseline data will help identify early warning signs of metal accumulation and guide nutrient management decisions, including feed formulation, manure application rates, and field selection. Ultimately, the findings will support farmers in maintaining healthy soils, protecting water quality, and reducing potential risks to livestock and crops—helping ensure efficient, sustainable dairy production while avoiding costly environmental or regulatory issues in the future.