Adaptive multi-paddock grazing management increases soil carbon and nitrogen stocks in southeastern U.S.

Abstract:

Continuous grazing has led to significant losses of carbon (C) in grassland soils. Supporting grassland management that increases soil C sequestration can mitigate rising CO₂ as well as improve the sustainability of the soil across a large area. Adaptive multi-paddock (AMP) grazing management is a more intense form of rotational grazing and shows potential to increase soil C stocks in grassland soils. To compare grazing management practices, our research analyzed soils from 10 grasslands in southeast United States representing either AMP or continuous grazing grassland management. We analyzed soil C and nitrogen (N) stocks as well as soil organic matter pools with different formation pathways and persistence in soils. Our results show that farms utilizing AMP grazing had 13% more soil C and 9% more N compared with continuously grazed farms. Additionally, most of the increase in soil C on AMP farms was in persistent soil organic matter pools. Greater soil N stocks combined with less enriched ¹⁵N values in AMP soils also suggest more efficient N cycling and higher N retention in AMP systems. These results demonstrate that AMP grazing could be implemented to sequester more C and hold on to more N, mitigating atmospheric greenhouse gas levels.