Today’s focus will be on rotational grazing, and how it can contribute to sequestering carbon in the soil.
What is Rotational grazing?
The whole pasture is divided in smaller paddocks, and the animals are moved through these paddocks in a planned sequence. Each paddock is grazed for a short period of time ( a day is very common but no more than 5 days), depending on the size of the paddocks, time of the year, and size of the grazing herd. This allows ample resting periods for the vegetation in the paddocks that are not being grazed, and gives it time to regrow properly, with increased nutrient content, and deeper root system.
Among the many benefits of rotational grazing is the fact that abundant perennial vegetation helps sequester carbon from the atmosphere in the soil.
What is Soil Carbon Sequestration?
Soil carbon sequestration is a process in which CO2 is removed from the atmosphere and stored in the soil carbon pool. This process is primarily mediated by plants through photosynthesis, with carbon stored in the form of SOC.
The carbon captured via soil carbon sequestration can be released if the soils are disturbed, and that’s why it’s so important that we switch from frequent tillage and annual crops to perennial crops and minimal disturbance of the soil.
Here are a few examples of research that has been done in this field.
Dr. Jason Rowntree of Michigan State University conducted an LCA (Life Cycle Assessment) of Multi-species pasture rotation (MSPR) on a farm in Southern US. Their conclusion:
“The 20-year MSPR chronosequence of soil C and other soil health indicators shows dramatic improvement since establishment, sequestering an average of 2.29 Mg C ha−1 yr−1. Incorporation of soil C sequestration into the
LCA reduced net GHG emissions of the MSPR by 80%, resulting in a footprint 66% lower than COM.”
This paper published in the Journal of Animal Science states:
“With appropriate management of grazing enterprises, soil function can be regenerated to improve essential ecosystem services and farm profitability. Affected ecosystem services include carbon sequestration, water infiltration, soil fertility, nutrient cycling, soil formation, biodiversity, wildlife habitat, and increased ecosystem stability and resilience.”
W R Teague, FORAGES AND PASTURES ... Journal of Animal Science, Volume 96, Issue 4, April 2018, Pages 1519–1530, https://doi.org/10.1093/jas/skx060
In this meta-analysis and review paper written by Viglizzo and Ricard in 2019: “results show that grazing lands generate C surpluses that could not only offset rural emissions, but could also partially or totally offset the emissions of non-rural sectors. The potential of grazing lands to sequester and store soil C should be reconsidered in order to improve assessments in future GHG inventory reports.”