Low quality evidence dominates discussion of carbon benefits of alternative grazing strategies

There is enormous interest in utilizing alternative grazing strategies to improve rangeland condition, increase profitability and decrease the carbon footprint of livestock production via soil organic carbon (SOC) sequestration. Here we present a systematic review and meta-analysis of the literature on alternative grazing strategies and their impact on SOC. Most studies (47 out of 70) failed multiple quality criteria. The 10 studies with 27 observations that met all inclusion criteria showed no change in SOC. Further dividing these observations by study design (controlled small-plot experiment versus observational paired site study) or grazing management style (adaptive or prescribed) or by aridity class or by grassland type failed to reveal any trends. Gains in SOC were only found for a secondary group of 13 studies with 25 observations, primarily composed of paired comparisons where there were unresolved questions about the quality of the site pairings for supporting causal inference. This divergence in results between primary and secondary studies highlights that low-quality evidence dominates the discussion around the climate benefits of alterative grazing strategies, underscoring a critical need for stronger evidence before asserting climate change mitigation benefits from alternative grazing practices. For submission to Communications Earth & Environment