Comparing Environmental Impacts of Beef Production Systems

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Impacts of soil carbon sequestration on life cycle greenhouse gas emissions in Midwestern USA beef finishing systems (2018)

• On-farm beef production and emissions data are combined with 4-year soil C analysis. • Feedlot production produces lower emissions than adaptive multi-paddock grazing. • Adaptive multi-paddock grazing can sequester large amounts of soil C. • Emissions from the grazing system were offset completely by soil C sequestration. • Soil C sequestration from well-managed grazing may help to mitigate climate change.

https://www.sciencedirect.com/science/article/pii/S0308521X17310338

Is the Grass Always Greener? Comparing the Environmental Impact of Conventional, Natural and Grass-Fed Beef Production Systems (2012)

The environmental impact of three beef production systems was assessed using a deterministic model.

• Conventional beef production (finished in feedlots with growth-enhancing technology) required the fewest animals, and least land, water and fossil fuels to produce a set quantity of beef.

• The carbon footprint of conventional beef production was lower than that of either natural (feedlot finished with no growth-enhancing technology) or grass-fed (forage-fed, no growth-enhancing technology) systems.

• All beef production systems are potentially sustainable; yet the environmental impacts of differing systems should be communicated to consumers to allow a scientific basis for dietary choices.

http://www.mdpi.com/2076-2615/2/2/127/htm


GRASSLAND MANAGEMENT AND CONVERSION INTO GRASSLAND: EFFECTS ON SOIL CARBON (2002)

We reviewed studies examining the influence of improved grassland management practices and conversion into grasslands on soil C worldwide to assess the potential for C sequestration.
Results from 115 studies containing over 300 data points were analyzed. Management improvements included fertilization (39%), improved grazing management (24%), conversion from cultivation (15%) and native vegetation (15%), sowing of legumes (4%) and grasses (2%), earthworm introduction (1%), and irrigation (1%). Soil C content and concentration increased with improved management in 74% of the studies, and mean soil C increased with all types of improvement.
Carbon sequestration rates were highest during the first 40 yr after treatments began and tended to be greatest in the top 10 cm of soil. Impacts were greater in woodland and grassland biomes than in forest, desert, rain forest, or shrubland biomes.
Conversion from cultivation, the introduction of earthworms, and irrigation resulted in the largest increases. Rates of C sequestration by type of improvement ranged from 0.11 to 3.04 Mg C·ha−1 yr−1, with a mean of 0.54 Mg C·ha−1·yr−1, and were highly influenced by biome type and climate. We conclude that grasslands can act as a significant carbon sink with the implementation of improved management.


http://onlinelibrary.wiley.com/doi/10.1890/1051-0761(2001)011%5B0343:GMACIG%5D2.0.CO;2/abstract


The environmental and economic impact of removing growth-enhancing technologies from U.S. beef production (2102)

The objective of this study was to quantify the environmental and economic impact of withdrawing growth-enhancing technologies (GET) from the U.S. beef production system.
...Withdrawing GET from U.S. beef production reduced productivity (growth rate and slaughter weight) and increased the population size required to produce 454 × 106 kg beef by 385 × 103 animals.
Feedstuff and land use were increased by 2,830 × 103 t and 265 × 103 ha, respectively, by GET withdrawal, with 20,139 × 106 more liters of water being required to maintain beef production.
Manure output increased by 1,799 × 103 t as a result of GET withdrawal, with an increase in carbon emissions of 714,515 t/454 × 106 kg beef.
The projected increased costs of U.S. beef produced without GET resulted in the effective implementation of an 8.2% tax on beef production, leading to reduced global trade and competitiveness. To compensate for the increase in U.S. beef prices and maintain beef supply, it would be necessary to increase beef production in other global regions, with a projected increase in carbon emissions from deforestation, particularly in Brazil.
Withdrawing GET from U.S. beef production would reduce both the economic and environmental sustainability of the industry.

https://academic.oup.com/jas/article/90/10/3527/4717884

Comparative life cycle environmental impacts of three beef production strategies in the Upper Midwestern United States (2010)

We used ISO-compliant life cycle assessment (LCA) to compare the cumulative energy use, ecological footprint, greenhouse gas emissions and eutrophying emissions associated with models of three beef production strategies as currently practiced in the Upper Midwestern United States.
Specifically we examined systems where calves were either: weaned directly to feedlots; weaned to out-of-state wheat pastures (backgrounded) then finished in feedlots; or finished wholly on managed pasture and hay. Impacts per live-weight kg of beef produced were highest for pasture-finished beef for all impact categories and lowest for feedlot-finished beef, assuming equilibrium conditions in soil organic carbon fluxes across systems.
A sensitivity analysis indicated the possibility of substantial reductions in net greenhouse gas emissions for pasture systems under conditions of positive soil organic carbon sequestration potential. Forage utilization rates were also found to have a modest influence on impact levels in pasture-based beef production. Three measures of resource use efficiency were applied and indicated that beef production, whether feedlot or pasture-based, generates lower edible resource returns on material/energy investment relative to other food production strategies.

[PDF] http://econ2.econ.iastate.edu/classes/crp274/swenson/CRP566/Readings/Leopold_2010-04-comparative-life-cycle-environmental-impacts-three-beef-production-strategies-upper-midwestern-unite.pdf https://www.sciencedirect.com/science/article/pii/S0308521X10000399