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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 aestivumL.) 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 CO2eq. 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.

Consumer demand for sustainably produced agricultural products is increasing. One approach that can be used to evaluate and compare product sustainability is to conduct a life cycle analysis (LCA). The term LCA is broadly used to describe a suite of analytical resources and standardized methods. Life cycle analyses are a transdisciplinary tool which can and are used by all professions but work best when conducted by teams with diverse skills and backgrounds. The objective of this paper is to provide a primer on LCAs for the agricultural community and for LCA practitioners unfamiliar with agronomy. Agricultural LCAs can differ greatly because agricultural products have multiple end uses, complex socio‐economic and environmental trade‐offs, and can be generated using a variety of different practices, resources, and production systems. Through worldwide agricultural marketing, intricate agronomic supply chains and support systems have been developed to produce, store, and distribute agricultural products. In many situations, the production practices are not linked to the products consumers purchase. This limitation can be partially overcome by conducting an LCA, which is a systematic summation of the multiple environmental impacts associated with the production, use, and disposal of a product. However, the large number and types of analyses can make it difficult for non‐practitioners and decision‐makers to use and interpret LCA results. It is important for members of the agricultural community to be aware of these analyses and how they can be used and how they affect product markets.

Integrated crop–livestock systems (ICLSs) can help increase food production while benefiting soils and the environment. This review summarizes recent impacts of ICLSs on crop and livestock production and rural economics and discusses lessons learned in the northern Great Plains (NGP). Research on ICLS conducted in the NGP indicates that the crop residue grazing, swath grazing, and annual forage grazing can positively influence crop production; whereas, livestock performance varies with season, forage nutritive value, and grazing management. Furthermore, ICLSs can reduce the costs and risks of agricultural production. The success of ICLSs in NGP region depends on trade‐offs, planning, economic benefits, policies, regulations, community acceptance, and management skills. The ICLSs could play a strategic role in future agricultural production. The lessons learned from adopting ICLSs in the NGP include the lack of available land for fertilizer (manure) management, that to implement ICLS practices skills and knowledge must be maintained, and ICLS provides an entry point for young farmers and ranchers however capital is needed. These experiences and lessons could be valuable references for producers to adopt ICLSs in the NGP or other regions. Core IdeasIntegrated crop–livestock systems positively affect crop production by improving soil health.Common integrated crop–livestock system management techniques can enhance the northern Great Plains crop production.Integrated crop–livestock system livestock performance is impacted by season, forage selection, and management.Integrated crop–livestock systems can increase economic benefits and reduce economic risks.Experiences and lessons in the northern Great Plains could be valuable for other regions to adopt integrated crop–livestock systems. Integrated crop–livestock systems positively affect crop production by improving soil health. Common integrated crop–livestock system management techniques can enhance the northern Great Plains crop production. Integrated crop–livestock system livestock performance is impacted by season, forage selection, and management. Integrated crop–livestock systems can increase economic benefits and reduce economic risks. Experiences and lessons in the northern Great Plains could be valuable for other regions to adopt integrated crop–livestock systems.

Environmental impacts attributable to beef feedlot production provide an opportunity for economically linked efficiency optimization. Eco‐efficiency models are used to optimize production and processes by connecting and quantifying environmental and economic impacts. An adaptable, objective eco‐efficiency model was developed to assess the impacts of dietary rations on beef feedlot environmental and fiscal cost. The hybridized model used California Net Energy System modeling, life cycle assessment, principal component analyses (PCA), and economic analyses. The model approach was based on 38 potential feedlot rations and four transportation scenarios for the US Great Plains for each ration to determine the appropriate weight of each impact. All 152 scenarios were then assessed through a nested PCA to determine the relative contributing weight of each impact and environmental category to the overall system. The PCA output was evaluated using an eco‐efficiency model. Results suggest that water, ecosystem, and human health emissions were the primary impact category drivers for feedlot eco‐efficiency scoring. Enteric CH4emissions were the greatest individual contributor to environmental performance (5.7% of the overall assessment), whereas terrestrial ecotoxicity had the lowest overall contribution (0.2% of the overall assessment). A well‐balanced ration with mid‐range dietary and processing energy requirements yielded the most eco‐ and environmentally efficient system. Using these results, it is possible to design a beef feed ration that is more economical and environmentally friendly. This methodology can be used to evaluate eco‐efficiency and to reduce researcher bias of other complex systems. Objective eco‐efficiency scores can be produced using principal component analyses.Large numbers of scenarios can be effectively assessed using eco‐efficiency scoring.Feedlot feed diets impact the sustainability of beef products.

As nonfood oilseed varieties are being rapidly developed, new varieties may affect agricultural production efficiency and life‐cycle assessment results. Current, detailed feedstock production information is necessary to accurately assess impacts of the biofuel life‐cycle. The life‐cycle impacts of four nonfood oilseeds (carinata [Brassica carinataL. Braun], camelina [Camelina satviaL. Crantz], canola or rapeseed [Brassica napusL.], and sunflower [Helianthus annuusL.]) were modeled using Argonne National Laboratory's GREET model to compare feedstocks for renewable biojet production using cold‐press oil extraction. Only feedstock‐related inputs were varied, allowing isolation of feedstock influence. Carinata and camelina performed slightly better than other oilseed crops at most product stages and impact categories as a result of current, low‐input agricultural information and new feedstock varieties. Between 40 to 50% of SOxand NOxemissions, ∼25% of greenhouse gas (GHG) emissions, and ∼40% of total energy consumption for the biojet production impact occurred during feedstock production. Within the first standard deviation, total well‐to‐tank emissions varied between ∼13% (GHG) and ∼35% (SOx) for all feedstocks emphasizing the importance of accurate agricultural production information. Nonfood oilseed feedstock properties (e.g., oil content, density) and agricultural management (e.g., fertilization, yield) affect life‐cycle assessment results. Using biofuels in feedstock production and focusing on low‐impact management would assist producers in improving overall product sustainability. Methods and varieties of nonfood oilseed agricultural production affect LCA results.LCA uncertainty estimations are needed due to variability in biomass production and feedstock traits.Feedstock production traits were found to influence the sustainability of biofuel processes.

Biofuel policy changes in the United States have renewed interest in soybean [Glycine max(L.) Merr.] biodiesel. Past studies with varying methodologies and functional units can provide valuable information for future work. A meta‐analysis of nine peer‐reviewed soybean life cycle analysis (LCA) biodiesel studies was conducted on the northern Great Plains in the United States. Results of LCA studies were assimilated into a standardized system boundary and functional units for global warming (GWP), eutrophication (EP), and acidification (AP) potentials using biodiesel conversions from peer‐reviewed and government documents. Factors not fully standardized included variations in N2O accounting, mid‐ or end‐point impacts, land use change, allocation, and statistical sampling pools. A state‐by‐state comparison of GWP lower and higher heating values (LHV, HHV) showed differences attributable to variations in spatial sampling and agricultural practices (e.g., tillage, irrigation). The mean GWP of LHV was 21.1 g·CO2–eq MJ−1including outliers, and median EP LHV and AP LHV was 0.019 g·PO4–eq MJ−1and 0.17 g·SO2–eq MJ−1, respectively, using the limited data available. An LCA case study of South Dakota soybean‐based biodiesel production resulted in GWP estimates (29 or 31 g·CO2–eq MJ−1; 100% mono alkyl esters [first generation] biodiesel or 100% fatty acid methyl ester [second generation] biodiesel) similar to meta‐analysis results (30.1 g·CO2–eq MJ−1). Meta‐analysis mean results, including outliers, resemble the California Low Carbon Fuel Standard for soybean biodiesel default value without land use change of 21.25 g·CO2–eq MJ−1. Results were influenced by resource investment differences in water, fertilizer (e.g., type, application), and tillage. Future biofuel LCA studies should include these important factors to better define reasonable energy variations in regional agricultural management practices.

Corn stover harvesting is a common practice in the western U.S. Corn Belt. This 5‐yr study used isotopic source tracking to quantify the influence of two tillage systems, two corn (Zea maysL.) surface residue removal rates, and two yield zones on soil organic C (SOC) gains and losses at three soil depths. Soil samples collected in 2008 and 2012 were used to determine 13C enrichment during SOC mineralization, the amount of initial SOC mineralized (SOClost), and plant C retained in the soil (PCRincorp) and sequestered C (PCRincorp− SOClost). The 30% residue soil cover after planting was achieved by the no‐till and residue returned treatments and was not achieved by the chisel plow, residue removed treatment. In the 0‐ to 15‐cm soil depth, the high yield zone had lower SOCloss(1.49 Mg ha−1) than the moderate yield zone (2.18 Mg ha−1), whereas in the 15‐ to 30‐cm soil depth, SOClosswas higher in the 60% (1.38 Mg ha−1) than the 0% (0.82 Mg ha−1) residue removal treatment. When the 0‐ to 15‐ and 15‐ to 30‐cm soil depths were combined, (i) 0.91 and 3.62 Mg SOC ha−1were sequestered in the 60 and 0% residue removal treatments; (ii) 2.51 and 0.36 Mg SOC ha−1were sequestered in the no‐till and chisel plow treatments, and (iii) 1.16 and 1.65 Mg SOC ha−1were sequestered in the moderate and high yield zone treatments, respectively. The surface treatments influenced C cycling in the 0‐ to 15‐ and 15‐ to 30‐cm depths but did not influence SOC turnover in the 30‐ to 60‐cm depth.

In the world's semi-arid regions, high crop demands have produced short term economic incentives to convert food production on native grasslands to dryland row crop food production, while genetic enhancements and equipment have reduced the risk of crop failure. The objectives of this paper were to discuss (1) the importance of considering the long-term sustainability of changing land use in semi-arid regions; (2) the impact of extreme climatic events on ecosystem functioning; and (3) factors contributing to higher crop yields in semi-arid regions. Semi-arid regions contain fragile areas where extreme climate events may be a tipping point that converts an apparent sustainable system to a non-sustainable ecosystem. However, semi-arid regions also contain zones where “better” management practices have reduced the agricultural impacts on the environment, increased soil carbon levels, and stimulated economic development. Research suggests that food production can be increased by enhancing the productivity of existing cropped land. However, this statement does not infer that crop production on all existing cropped lands in semi-arid regions is sustainable. Worldwide, targeted research should be conducted to clearly identify local barriers to conservation practice adoption and identify the long-term ramifications of extreme climatic events and land-use changes on semi-arid ecosystem functioning.

Environmental context Uranium and arsenic, two elements of human health concern, are commonly found at sites of uranium mining, but little is known about processes influencing their environmental behaviour. Here we focus on understanding the chemical and physical processes controlling uranium and arsenic transport at an abandoned uranium mine. We find that the use of sedimentation ponds limits the mobility of uranium; however, pond conditions at our site resulted in arsenic mobilisation. Our findings will help optimise restoration strategies for mine tailings. Abstract Although As can occur in U ore at concentrations up to 10wt-%, the fate and transport of both U and As at U mine tailings have not been previously investigated at a watershed scale. The major objective of this study was to determine primary chemical and physical processes contributing to transport of both U and As to a down gradient watershed at an abandoned U mine site in South Dakota. Uranium is primarily transported by erosion at the site, based on decreasing concentrations in sediment with distance from the tailings. Sequential extractions and U X-ray absorption near-edge fine structure (XANES) fitting indicate that U is immobilised in a near-source sedimentation pond both by prevention of sediment transport and by reduction of UVI to UIV. In contrast to U, subsequent release of As to the watershed takes place from the pond partially due to reductive dissolution of Fe oxy(hydr)oxides. However, As is immobilised by adsorption to clays and Fe oxy(hydr)oxides in oxic zones and by formation of As–sulfide mineral phases in anoxic zones down gradient, indicated by sequential extractions and As XANES fitting. This study indicates that As should be considered during restoration of uranium mine sites in order to prevent transport.

A life‐cycle assessment (LCA) model was developed to estimate the environmental impacts associated with four different U.S. Northern Great Plains (NPG) beef production systems. The LCA model followed a “cradle‐to‐gate” approach and incorporated all major unit processes, including mineral supplement production. Four distinct operation scenarios were modeled based on production strategies common to the NGP, and a variety of impacts were determined. The scenarios include a normal operation, early weaning of the calf, fast‐tack backgrounding, and grassfed. Enteric emissions and manure emissions and handling were consistently the largest contributors to the LCA impacts. There was little variability between production scenarios except for the grassfed, where the greenhouse gas (GHG) emissions were 37% higher due to a longer finishing time and lower finishing weight. However, reductions to GHG emissions (15–24%) were realized when soil organic carbon accrual was considered and may be a more realistic estimate for the NGP. Manure emissions and handing were primary contributors to potential eutrophication and acidification impacts. Mitigation strategies to reduce LCA impacts, including diet manipulation and management strategies (i.e., treatment of manure), were considered from a whole‐systems perspective. Model results can be used for guidance by NGP producers, environmental practitioners, and policymakers.