Uneven nutrient distribution in dairy farm soils: implications for environmental sustainability in the Argentine Pampas

Pasture-based livestock systems are often regarded as restorative for soil fertility. However, this study hypothesizes that the intensification of dairy farming leads to spatial and vertical imbalances in soil nutrient distribution, undermining this assumption. We assessed macronutrients, micronutrients, and chemical indicators in 240 soil samples from 17 dairy farms across the Argentine Pampas, comparing reference soils, grazed pastures, feeding pens, and adjacent croplands at three depths (0–20, 20–40, and 40–60 cm). Results revealed substantial nutrient depletion in grazed pastures and croplands, especially for phosphorus (− 48% to − 82%), potassium (− 24% to − 43%), and zinc (− 67% to − 74%), with deeper layers most affected. In contrast, feeding pens exhibited strong surface nutrient accumulation. A marked gradient of nutrient decline was detected with distance from milking barns. These findings challenge the prevailing assumption of pasture-driven soil restoration and highlight the environmental risks of unmanaged nutrient accumulation. Our results underscore the need for targeted nutrient redistribution strategies and call for a reevaluation of current paradigms regarding pasture-based sustainability in livestock systems.