Positive relationships between plant species diversity, soil microbial function and nutrient cycling have been well documented in natural systems, and these relationships have the potential to improve the production and sustainability of agroecosystems. Our objectives were to study the long-term effects of planted species composition and nitrogen (N) fertilization on soil microbial biomass C, extracellular enzyme activity, changes in total soil C, soil fertility and aboveground biomass yield in mixtures of native prairie species managed with and without N fertilizer for bioenergy production at four sites in Minnesota (MN), USA. Species were sown into mixture treatments and composition was not maintained (i.e., no weeding) throughout the duration of the study. Species mixture treatments at establishment included a switchgrass (Panicum virgatum L.) monoculture (SG), a four-species grass mixture (GM), an eight-species legume/grass mixture (LG) and a 24-species high diversity forb/legume/grass mixture (HD). Species diversity and aboveground productivity were similar for most mixture treatments at final sampling after 11 or 12 years of succession. Despite this homogenization of productivity and diversity throughout the study, the effects of planted species diversity and a decade of succession resulted in some differences in soil variables across species mixture treatments. On a peat soil in Roseau, MN, soil enzyme activities including β-glucosidase (BG), cellobiohydrolase (CBH) and phosphatase (PHOS) were highest in HD compared to GM treatments. On a sandy soil at Becker, MN, total soil C increased in all treatment combinations at the 0–15 and 15–30 cm depth intervals, with SG showing greater increases than HD at the 15–30 cm depth. Final soil pH also varied by species mixture at the Becker and Roseau sites, but differences in treatment comparisons varied by location. Nitrogen fertilization did not affect any response variable alone, but interacted with species mixture treatment to influence PHOS and total soil C at Becker. The inconsistent effects of species mixture and N fertilization on soil biological and chemical properties observed across sites highlight the importance of local soil and climate conditions on bioenergy and ecosystem service provisioning of perennial bioenergy cropping systems.

Unplowed native grasslands are among the most endangered ecosystems in the world, due in large part to their agricultural suitability and widespread conversion to cropland. Despite this, remaining locations of these species- and carbon-rich landscapes are neither well monitored nor effectively protected. A recent spike in US prices for corn (Zea mays) and soybeans (Glycine max) intensified incentives to bring new land into production, potentially hastening the conversion of grasslands to crops. We combined satellite-based land cover data with aerial photographs and a field-based inventory of remaining native grassland (hereafter prairie) in Minnesota to assess the areas, rates, and locations of prairie conversion since 2008. Our results reveal that during 2008–2012, prairie was converted at average annual rates more than four times greater than the previous decade and a half. Corn and soybeans were the initial crops planted on 73% of converted prairie, and more than 80% of conversion occurred in recently established conservation priority zones, thereby magnifying the urgency to protect these sites. Broader land-use trends in Minnesota suggest that expansion of both croplands and developed lands continues to threaten all grasslands, including the subset that is prairie, and that the growth of developed or built-up land may be amplifying the conversion pressure exerted by agriculture, though further research is needed. Despite the small total area of prairie lost, the multi-fold increase in conversion rates and the confirmation of native habitat clearing may have substantial conservation implications, especially given the very limited prairie that remains in the region. The overall results reveal challenges for federal policies, including a loophole in the crop insurance Sodsaver provision surrounding alfalfa hay and limitations in the current enforcement of the Renewable Fuel Standard.

Switchgrass is a potential feedstock for cellulosic bioenergy production. Weed competition from annual grass during the establishment year can reduce switchgrass establishment and resulting productivity, but the relationship between early season grass densities and outcomes of competition are not well understood. We measured how a range of giant and yellow foxtail densities in the establishment year influenced switchgrass establishment and resulting productivity in the first production year (second year of the growing season). In two of the three site–yr more than four foxtail plants m−2 reduced switchgrass plant densities below documented thresholds of establishment success. A lesser effect of foxtails in the third site–year suggested that higher switchgrass emergence rates reduced foxtail competitive ability during establishment. Effects on yield were consistent over the three site–yr. The yield (10.96 Mg ha−1 ± 0.77) decreased rapidly as foxtail density increased. One foxtail plant m−2 reduced switchgrass yield in the first production year by 25%, and yield loss was 90% or greater at densities > 50 foxtail plants m−2. Although switchgrass can establish in the presence of foxtail competition, these weed species should be controlled to maximize yields in the first production year.

The integration of sustainable development goals in the international sales contracts of biofuels highlights a new role for international contract law. This article examines how the substantive rules of the UN Convention on International Sale of Goods (CISG) may contribute to the implementation of sustainable development and the applicability of the “sustainability clauses.” The contracting parties, including the final buyers of a global supply chain have the right to demand enforcement of these contractual clauses. However, the CISG is limited as to the legal effects international contracts have for third-parties that benefit or are interested in the sustainable development of biofuels. In this context, the contractual tool used in the international trade of sustainable products becomes not only useful but also indispensable.

Biofuels such as ethanol and biodiesel are increasingly promoted as green alternatives to petroleum-derived transport fuels. Scaling up feedstock production to produce enough biofuel to displace a significant portion of current petroleum demand will put pressure on land and water resources both domestically and internationally, however, and could potentially be accompanied by unacceptable changes in landscape-level land use patterns and provisioning of ecosystem services. Ensuring that feedstock production is sustainable and that biofuels provide the social and environmental benefits that are often attributed to them will require a carefully designed portfolio of agricultural, forestry, energy, and trade policies related to biofuels and feedstock production. Despite the difficulties associated with development and application of such policies, they should be in place before further policy incentive is provided for expansion of biofuel industries.

The relationship between complete-feed prices and ingredient prices is estimated in order to analyze the effect of higher commodity prices on feed costs, with particular attention paid to the substitutability of corn distillers dried grains with solubles (DDGS). Using the historical price correlation between corn and DDGS, each $1 per ton increase in the price of corn increases feed costs between $0.45 and $0.59 per ton across livestock sectors. Marginal feed costs based on lower forecasted price correlations are reduced between $0.05 to $0.12 per ton across livestock sectors, but only for the dairy ration is the reduction statistically significant. Overall, DDGS cost savings are relatively limited and insufficient to offset the impact of other higher-priced feedstocks.

We determine how the U.S. ethanol tax credit and import tariff affect the corn-ethanol-gasoline markets and how farm subsidies interact with these policies. We show how the ethanol tax credit and import tariff each uniquely affect the ethanol and gasoline prices. The ethanol import tariff alone increases the terms of trade in ethanol imports and corn exports, but decreases the terms of trade in gasoline imports and the tax costs of farm price supports. With price-contingent farm subsidies in place, the optimal tariff and tax credit will depend on the price level. When farm subsidy expenditures are high, import subsidies for ethanol may increase social welfare due to the substantial size of the fuel market relative to the corn market.

Two seemingly unrelated topics are discussed—an outlook for biofuels in the southern United States, along with an overview of the important role that information technology is playing in the fuel ethanol industry. The outlook discussion is limited to issues involving the two principal biofuels, fuel ethanol and biodiesel, and their respective feed stocks, corn and soybean oil. The two topics are linked with a description of how information technology (IT) has enabled the development of the fuel ethanol franchise and a discussion of how IT is changing the very nature of biofuel operations.

Despite large-scale investments and government mandates to expand biofuels development and infrastructure in the United States, little is known about how the public conceives of this alternative fuel technology. This study examines public opinion of biofuels by focusing on citizen knowledge and the motivated processing of media information. Specifically, we explore the direct effects of biofuels knowledge and the moderating effect of partisanship on the relationship between media use and benefit vs. risk perceptions in the following four domains: environmental impacts, economic consequences, ethical/social implications, and political ramifications. Our results suggest that more knowledgeable respondents see fewer benefits of biofuels relative to risks, and that Democrats and Republicans are affected differently by media use when forming opinions about biofuels. Among Democrats, greater attention to political media content leads to a more favorable outlook toward the technology across several domains of interest, while among Republicans, an increase in attention to political content has the opposite effect. Possible reasons for these results, as well as implications of the findings at the intersection of politics and the life sciences, are discussed.

This article presents current investment and operating costs of ethanol and biodiesel plants for alternative prices of feedstock. The price of these two fuels is estimated for alternative prices of crude oil with the existing renewable fuels policy. The excise tax credit, currently $0.51 per gallon of ethanol and $1.00 per gallon of biodiesel, is a major contributor to the fuel price and profitability of these industries. The analysis demonstrates how the crude oil price, feedstock price, and excise tax credits interact to impact profitability of these industries.

Analysis of the potential to supply 25% of projected 2025 U.S. transportation fuels indicates sufficient biomass resources are available to meet increased demand while simultaneously meeting food, feed, and export needs. Corn and soybeans continue to be important feedstocks for ethanol and biodiesel production, but cellulose feedstocks (agricultural crop residues, energy crops such as switchgrass, and forestry residues) will play a major role. Farm income increases, mostly because of higher crop prices. Increased crop prices increase the cost of producing biofuels.

As the hunt for renewable energy sources from agriculture intensifies, many agricultural producers are contemplating what crops to grow in the foreseeable future. On the one hand, there are traditional food crops, such as soybean, corn, and wheat, which have recently enjoyed a spike in prices, primarily because of the seemingly ever-growing demands of the corn to ethanol industry. On the other hand, there are the lesser-known perennial energy crops, such as switchgrass. Although much information on various aspects of switchgrass production exists, this paper discusses the adaptation of existing production and processing information to Arkansas conditions as a potential alternative to crop production.

As a result of the increase in the real cost of fossil fuel-based energy in recent years, federal and state governments have taken a more active role in energy policy by creating incentives to develop alternative sources of energy, including biofuels. However, policymakers often become focused on the specific type of energy and not the energy services consumers ultimately value. The lack of recognition of energy as a commodity results in policies that ignore the characteristics of the associated markets: easy entry and exit, no barriers to entry, and sensitivity to changes in supply and demand. Consequently, energy industries may fail to arise because entrepreneurs must be able to account for all costs and earn—at a minimum—a competitive return on the investment. This article evaluates the options available to policymakers related to biofuels, which are of particular concern to the South, and includes an assessment of the knowledge base on which policy decisions are made.

U.S. ethanol production capacity increased more than threefold between 2002 and 2008. We study the effect of this growth on corn acreage. Connecting annual changes in county-level corn acreage to changes in ethanol plant capacities, we find a positive effect on planted corn. The building of a typical plant is estimated to increase corn in the county by over 500 acres and to increase acreage in surrounding counties up to almost 300 miles away. All ethanol plants are estimated to increase corn production by less than their annual requirements.