|SHRESTHA, PRASHANSA - South Dakota School Of Mines And Technology|
|KARIM, RIFAT - South Dakota School Of Mines And Technology|
|SIEVERDING, HEIDI - South Dakota School Of Mines And Technology|
|KUMAR, SANDEEP - South Dakota State University|
|NLEYA, THANDI - South Dakota State University|
|GRAHAM, CHRISTOPHER - South Dakota State University|
|STONE, JAMES - South Dakota School Of Mines And Technology|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2020
Publication Date: 11/30/2020
Citation: Shrestha, P., Karim, R., Sieverding, H.L., Archer, D.W., Kumar, S., Nleya, T., Graham, C.J., Stone, J.J. 2020. Life cycle assessment of wheat production and wheat-based crop rotations. Journal of Environmental Quality. 49:1515– 1529. https://doi.org/10.1002/jeq2.20158.
Interpretive Summary: Information is needed on the long-term sustainability of crop rotation practices in dryland areas of the northern Great Plains. Life cycle assessment and economic analysis were used to evaluate the environmental and economic performance of fourteen crop rotations in a 13-year field study. Impacts considered included land use, climate change potential, and two measures of water quality impacts (eutrophication, and ecotoxicity). Results showed that no single rotation performed well in all categories of impacts. Using a single endpoint damage score, rotations that include oilseeds and legumes with wheat had the best environmental impact. Economic analysis showed that crop insurance policies improved diversification economics by 20%. These results are important for extension personnel and farmers in identifying rotations that can help them improve profitability and long-term sustainability.
Technical Abstract: In the northern Great Plains (NGP), wheat is the primary grain commodity. There is a need for the NGP to have a detailed analysis of environmental impacts for wheat-based agricultural production systems to better understand regional agroecosystems. This article provides a cradle-to-field gate life cycle assessment (LCA) for NGP dryland wheat (Triticum aestivum L.) production. The environmental impacts for winter wheat production using crop rotation and agricultural intensification are quantified. Fourteen no-till crop rotations ranging in duration from 2 to 6 yr were evaluated and compared using data from a historical 13-yr replicated rotation study (>300 observations). Midpoint LCA categories chosen for this comparison are energy, agricultural land use, climate change potential, freshwater eutrophication, and freshwater ecotoxicity due to their direct links with agricultural management practices. The NGP farmers commonly use a fallow period every other year due to moisture limitations. This specific agricultural practice and allocations within rotations are critical considerations within agricultural LCAs. Two aspects of fallow considerations and a sensitivity analysis were also performed. The allocated midpoint impacts between crops in rotational studies averaged 0.31, 0.79, 0.62, and 0.63 kg CO2 eq. per unit of winter wheat when energy, economic, mass, and cereal unit allocations were used, respectively. Economic analysis of the studied experimental crop was performed; results demonstrated that crop insurance policies improved diversification economics by 20%. Agricultural diversification benefits and burdens were better represented by endpoint damage assessments than by midpoint impact analysis.