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

Abstract

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.

Surface‐soil carbon stocks greater under well‐managed grazed pasture than row crops

“…Soil organic C positively correlated with pasture age suggesting that soil C may accumulate in pastures, albeit slowly. Whereas this correlation was relatively weak when using the SOC difference, a stronger relationship was observed for pasture SOC, which included additional points, and POM-C. An increase in SOC over time aligns with previous research (Franzluebbers et al, 2012;Rowntree et al, 2020) but estimates of accumulation rates widely differ (Jackson, 2022). In particular, the slope of the relationship between the SOC differences and pasture SOC with pasture age might be inferred as the rate of soil C accumulation (0.32 and 0.31 Mg C ha −1 yr −1 , respectively).…”

Reducing climate impacts of beef production: A synthesis of life cycle assessments across management systems and global regions

“…Long‐term dynamics of soil C sequestration on grazed lands must also be assessed, since C sequestration rates in soils typically decline after initial increases that can occur with improved management (Schmidt et al, 2011; Six et al, 2002). For example, soil C stocks increased rapidly for 6 years after conversion of degraded row cropland to intensive rotational grazing in three farms in the southeastern USA, but then C sequestration rates plateaued (Machmuller et al, 2015), and soil C stocks appeared to increase for the first 13 out of 20 years in a chronosequence study in similar sites in the southeastern USA using multi‐species pasture rotation (Rowntree et al, 2020). Nonetheless, even the shorter‐term recovery of previously existing soil C on grazed lands presents a feasible and substantial reduction in beef GHG emissions, and should be pursued to mitigate climate change.…”

Behavioral Characteristics and Self-Reported Health Status among 2029 Adults Consuming a “Carnivore Diet”

“…Intensive animal production, typically with use of commodity grains and soy for feed, causes significant environmental harms and raises ethical issues about animal treatment. These concerns may be mitigated, to some degree, with integrated, pasture-based agricultural systems ( 60 ) and other interventions, such as the use of algal feed additives to reduce greenhouse gas production ( 61 , 62 ). For context, industrial-scale, commodity grain monoculture may also cause substantial environmental impacts and loss of wildlife.…”