Rotational Grazing Can Build Soil Carbon, but Drought Changes the Story
A study led by Dr. Merilynn Schantz examined how alternative and prevailing grazing strategies influenced soil health and nutrient dynamics over a 10-year period. The researchers compared rotational grazing with supplemental cover-crop grazing against more conventional continuous grazing with supplemental forage oats.
Why It Matters
Grazing management can influence soil carbon, nutrient cycling, plant productivity, and the potential for nutrient losses. However, these effects develop over years and are strongly influenced by environmental conditions.
Long-term studies are particularly valuable because short-term measurements may capture temporary responses to rainfall, drought, or grazing rather than persistent changes in soil function. This study followed pasture systems across a decade, allowing the researchers to evaluate how management and weather interacted over time.
What the Study Found
The alternative grazing system, which incorporated rotational grazing and supplemental cover crops, generally supported greater total and organic soil carbon than the prevailing grazing system. In contrast, soils under prevailing management showed greater concentrations of readily leachable phosphorus.
But management was not the only factor controlling soil health. Soil nutrient concentrations changed substantially among years, and drought conditions were associated with declines in soil carbon. The results demonstrate that soil-health responses in grazing systems reflect an interaction among management, weather, plant production, and inherent soil conditions.
Key Takeaway
Rotational grazing and cover crops can support soil carbon and influence nutrient cycling, but soil-health improvements do not occur independently of weather.
For producers, this means that changes in soil health should be evaluated over multiple years rather than judged from a single soil test. Management matters, but rainfall patterns, drought, and year-to-year variability can strongly influence the results.
Reference: Schantz, M. C., Smith, D. R., Adhikari, K., Osorio, L. M., Tolleson, D. R., Goodwin, J. J., Thorp, K. R., & Harmel, R. D. (2026). Soil health and nutrient dynamics in pasturelands: A decadal study on the effects of alternative vs. prevailing grazing management. Agriculture, Ecosystems & Environment, 397, 110053. https://doi.org/10.1016/j.agee.2025.110053
