Ecosystem Impacts and Productive Capacity of a Multi-Species Pastured Livestock System ⋆ Savory Institute

Science Article

Ecosystem Impacts and Productive Capacity of a Multi-Species Pastured Livestock System

Rowntree JE, Stanley PL, Maciel ICF, Thorbecke M, Rosenzweig ST, Hancock DW, Guzman A and Raven MR (2020) Ecosystem Impacts and Productive Capacity of a Multi-Species Pastured Livestock System. Front. Sustain. Food Syst. 4:544984. doi: 10.3389/fsufs.2020.544984

Key Takeaways

This paper, written by Savory Hub leader Dr. Jason Rowntree of Michigan State University, conducted a whole-farm life cycle assessment (LCA) of a multi-species pasture rotation (MSPR) farm in the southeastern United States, White Oak Pastures that was originally converted from degraded cropland and is now practicing Holistic Planned Grazing (HPG).
They compared the production outputs, greenhouse gas (GHG) emissions, land footprints, and soil health outcomes to a conventional, commodity (COM) production system of each respective species.
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.
However, when comparing required land between the two systems for food production, MSPR required 2.5 times more land when compared to COM. Thus, while the model indicates that MSPR can simultaneously produce protein while regenerating land, a considerably greater land area is needed when compared to COM.
The authors note that "results present an important yet paradoxical conclusion on land and food production balance," though Savory offers the opinion that land usage is an irrelevant metric to focus on with holistically managed land since its increasingly productive pastures are not displacing wildlife habitat but rather creating it. Only land usage for cropland, which is former wildlife habitat, should be of concern.

Summary

Regenerative agriculture is a newly codified approach to agriculture that emphasizes reducing reliance on exogeneous inputs, as well as restoring and enhancing ecosystem services such as soil carbon (C) sequestration. These regenerative agriculture principles suggest that modern livestock systems can be redesigned to better capitalize on animals' ecological niche as biological up cyclers and may be necessary to fully regenerate some landscapes. One example is a multispecies pasture rotation (MSPR) system, which symbiotically stacks multiple animal production enterprises (i.e., chickens, cattle, sheep, and pigs) on one landscape. We conducted a whole-farm life cycle assessment (LCA) of an MSPR in the southeastern United States that was originally converted from degraded cropland. We compared the production outputs, greenhouse gas (GHG) emissions, land footprints, and soil health outcomes to a conventional, commodity (COM) production system of each respective species. Our 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. However, when comparing required land between the two systems for food production, MSPR required 2.5 times more land when compared to COM. Thus, while our model indicates that MSPR can simultaneously produce protein while regenerating land, a considerably greater land area is needed when compared to COM. Our results present an important yet paradoxical conclusion on land and food production balance. Should society prioritize an input-intensive, COM system that produces more food from a smaller yet degrading land base? Or, alternatively, should systems such as MSPR that produce less food on a larger, but more ecologically functional landscape be more highly prioritized? These complexities must be considered in the global debate of agricultural practice and land. Our results indicate MSPRs are a useful model for alternative livestock production systems with improved environmental outcomes, but in this study may present considerable land-use tradeoffs.