Managing Intensive Rotational Grazing for Soil Carbon

9115068">Management intensive grazing (MIG) is a practice where large numbers of livestock graze on a small pasture for a short period before moving onto the next paddock. In addition to allowing organic livestock producers to meet National Organic Program requirements for dry matter intake, MIG may also have added benefits for livestock agroecosystem performance that include increased plant biomass production, improved forage species composition, and enhanced soil carbon storage. Few studies have demonstrated these benefits, particularly those related to soil carbon sequestration. Quantifying the perceived benefits of MIG through measurements, models, or an integrated data-model framework is challenging given the inherent spatial and temporal variation of livestock herds moving across a heterogeneous landscape. The goal of this study is to couple spatiotemporally intensive measurements of plant biomass, soil carbon, and livestock management with the 9115068">DeNitrification-DeComposition9115068"> (DNDC) model to examine whether and how MIG might enhance forage production and soil carbon sequestration while minimizing greenhouse gas emissions. We sampled plant biomass production, soil carbon stocks, and greenhouse gas fluxes within hayed and grazed fields of three organic dairy farms in the northeastern U.S. located in New Hampshire, Maine, and Vermont. We found that none of the agroecosystem attributes we measured varied between management systems. At one of our sites, we also monitored change in soil carbon content over time as the pasture transitioned from hay to intensive grazing management and found no difference in carbon storage with the implementation of MIG. We then parameterized the DNDC model to represent MIG within our study farms and conducted sensitivity analyses to explore management practices that farmers might apply to achieve greater plant biomass productivity and/or enhanced soil carbon storage using MIG. Overall, our study highlights how management strategies such as MIG do not always enhance agroecosystem performance, and that process-based models can clarify tradeoffs when managing 9115068">livestock systems 9115068">to achieve specific performance aims. 5559740":240}"="201341983":0,"335559737":27,"335559739":160,"335559740":240}"">