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Abstract

Advanced biomass feedstocks tend to provide more non-fuel ecosystem goods and services (ES) than 1st-generation alternatives. We explore the idea that payment for non-fuel ES could facilitate market penetration of advanced biofuels by closing the profitability gap. As a specific example, we discuss the Mississippi-Atchafalaya River Basin (MARB), where 1st-generation bioenergy feedstocks (e.g., corn-grain) have been integrated into the agricultural landscape. Downstream, the MARB drains to the Gulf of Mexico, where the most-valuable fishery in the US is impacted by annual formation of a large hypoxic "Dead zone." We suggest that advanced biomass production systems in the MARB can increase and stabilize the provision of ES derived from the coastal and marine ecosystems of the Gulf-of-Mexico. Upstream, we suggest that choosing feedstocks based on their resistance or resilience to disturbance (e.g., perennials, diverse feedstocks) can increase reliability in ES provision over time. Direct feedbacks to incentivize producers of advanced feedstocks are currently lacking. Perhaps a shift from first-generation biofuels to perennial-based fuels and other advanced bioenergy systems (e.g., algal diesel, biogas from animal wastes) can be encouraged by bringing downstream environmental externalities into the market for upstream producers. In future, we can create such feedbacks through payments for ES, but significant research is needed to pave the way.

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... For example it can be valuable in the development of market-based instruments that can improve biofuel sustainability (e.g. payment for ecosystem services schemes) [68,69], or change the conception of what is considered marginal land, which has become an integral element of the biofuel sustainability discourse [70]. ...
... They use a series of econometric tools to assess household-level linkages between sugarcane production and food crop production. [72] USA Multiple X --Romeu-Dalmau et al. [73] Malawi, Mozambique, Swaziland Sugarcane, jatropha X --Mudombi et al. [74] Malawi, Mozambique, Swaziland Sugarcane, jatropha X -de Hoop [75] India Oilseed trees X --Ortolan et al. [76] Brazil Sugarcane X --Thakrar et al. [77] USA Switchgrass X X -Gissi et al. [78] Italy Soybeans, sunflower, rapeseed X X -Herrmann et al. [79] Malawi Sugarcane X --Ahmed et al. [70] Ghana Jatropha X X Jager and Efroymson [68] USA Perennial grasses --X Woodbury et al. [69] USA Maize, switchgrass -X X Dale et al. [80] USA Perennial grasses -X X Gasparatos et al. [81] Multiple Multiple -X X ...
... By making these trade-offs explicit they argue how an ecosystem services perspective can inform where to locate biofuel projects. Jager and Efroymson [68] argue how a switch from maize to perennial grasses for ethanol feedstock can provide various regulating ecosystem services related to water purification. They use the Mississippi-Atchafalaya River Basin (MARB) as an example to make the case that this switch can have significant benefits downstream by reducing hypoxia in the Gulf of Mexico. ...
... conversion of miombo woodlands for sugarcane/jatropha production) [66,75]. In developed countries such as the EU and the US, most of the production of conventional feedstock such as maize and rapeseed takes place in already converted agricultural areas [56,76]. However, depending on the geography, structure of markets and sustainability safeguards, biofuel policies in developed countries could potentially induce feedstock expansion in developing countries, therefore having faraway impacts on habitats and biodiversity [78]. ...
... On the other hand some lingo-cellulosic feedstocks require lower amounts of fertilizers and pesticides compared to the intensive production of annual crops (e.g. maize), thereby having positive effects on water quality [76]. It is worth noting that these effects on aquatic ecosystems can materialize far away from the areas of feedstock/biofuel production [76,88,89]. ...
... maize), thereby having positive effects on water quality [76]. It is worth noting that these effects on aquatic ecosystems can materialize far away from the areas of feedstock/biofuel production [76,88,89]. For example, maize production following current agricultural management practices can increase nutrient loading along the Mississippi basin, leading to higher levels of hypoxia in the Gulf of Mexico [90][91][92]. ...
Article
Biofuel feedstock production can be a significant driver of landscape modification, ecosystem change and biodiversity loss. There is growing body of literature that shows how biofuel landscapes provide various ecosystem services (e.g., feedstock for fuel, carbon sequestration) and compromise other ecosystem services (e.g., food, freshwater services). These effects are context-specific and depend largely on prior land use conditions and feedstock production practices. Changes in the flow of ecosystem services due to the conversion of natural and agricultural areas can have ripple effects on human wellbeing. Despite some recent attempts to apply to biofuel settings concepts and methods rooted in the ecosystem services literature, this is the exception rather than the rule within both the biofuel and the ecosystem services research communities. This paper synthesizes the current knowledge about the impact of biofuels on ecosystem services. It focuses especially on the feedstock production phase and outlines the main mechanisms through which landscape conversion affects the provisions of ecosystem services. It proposes conceptually coherent indicators to reflect these mechanisms and offers a critical discussion of key issues at the interface of biofuels and ecosystem services.
... Generally, an overabundance of nutrients (mainly phosphorous and nitrogen) in water bodies can deteriorate water quality and affect aquatic life. However, it is shown that the production of some dedicated energy crops on agricultural landscapes can help to reduce these impacts by intercepting nutrient run-off to water bodies and benefit downstream ecosystems [94,95]. Therefore, these are synergies with water quality (SDG 6) and life below water (SDG 14). ...
... For example, it was reported that growing perennials on land previously in use for (intensively) managed corn and soy bean decreased nutrient loading at the watershed/basin level (SDG 6.3) and helped to prevent downstream hypoxia episodes, thus benefitting aquatic life (14.1) [94]. Synergies with biodiversity conservation were reported for several locations (e.g., the USA, Germany and the Netherlands) [30,59,69,70,72]. ...
Article
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Bioenergy aims to reduce greenhouse gas (GHG) emissions and contribute to meeting global climate change mitigation targets. Nevertheless, several sustainability concerns are associated with bioenergy, especially related to the impacts of using land for dedicated energy crop production. Cultivating energy crops can result in synergies or trade-offs between GHG emission reductions and other sustainability effects depending on context-specific conditions. Using the United Nations Sustainable Development Goals (SDGs) framework, the main synergies and trade-offs associated with land use for dedicated energy crop production were identified. Furthermore, the context-specific conditions (i.e., biomass feedstock, previous land use, climate, soil type and agricultural management) which affect those synergies and trade-offs were also identified. The most recent literature was reviewed and a pairwise comparison between GHG emission reduction (SDG 13) and other SDGs was carried out. A total of 427 observations were classified as either synergy (170), trade-off (176), or no effect (81). Most synergies with environmentally-related SDGs, such as water quality and biodiversity conservation, were observed when perennial crops were produced on arable land, pasture or marginal land in the ‘cool temperate moist’ climate zone and ‘high activity clay’ soils. Most trade-offs were related to food security and water availability. Previous land use and feedstock type are more impactful in determining synergies and trade-offs than climatic zone and soil type. This study highlights the importance of considering context-specific conditions in evaluating synergies and trade-offs and their relevance for developing appropriate policies and practices to meet worldwide demand for bioenergy in a sustainable manner.
... Referring to sustainability criteria as 'constraints' implies that algae have significant adverse impacts on the environment. On the contrary, algae production can supply additional ecosystem services that benefit society [9,10]. Algae production can potentially lower carbon emissions [11] and remove nutrients in wastewater [12,13], thereby providing both climate regulation [14] and water purification services [15]. ...
... In the next analysis, we evaluated the effect of setting higher thresholds for water surplus on stream habitat (extreme low flows and high temperatures) in representative streams for each HUC8 basin over the historical period from 1 January 1985 to 31 December 2016. Following the approach described by [10], we characterized extreme events over the historical period of record and selected suitable indicators for low flow and high temperature. ...
Article
Sustainable production of algae will depend on understanding trade-offs at the energy-water nexus. Algal biofuels promise to improve the environmental sustainability profile of renewable energy along most dimensions. In this assessment of potential US freshwater production, we assumed sustainable production along the carbon dimension by simulating placement of open ponds away from high-carbon-stock lands (forest, grassland, and wetland) and near sources of waste CO 2. Along the water dimension, we quantified trade-offs between water scarcity and production for an 'upstream' indicator (measuring minimum water supply) and a 'downstream' indicator (measuring impacts on rivers). For the upstream indicator, we developed a visualization tool to evaluate algae production for different thresholds for water surplus. We hypothesized that maintaining a minimum seasonal water surplus would also protect river habitat for aquatic biota. Our study confirmed that ensuring surplus water also reduced the duration of low-flow events, but only above a threshold. We also observed a trade-off between algal production and the duration of low-flow events in streams. These results can help to guide the choice of basin-specific sustainability targets to avoid conflicts with competing water users at this energy-water nexus. Where conflicts emerge, alternative water sources or enclosed photobioreactors may be needed for algae cultivation.
... In this case, the water quality improvements projected to result from perennial switchgrass plantings (i.e., reduced sediment and nutrient runoff) were found to improve fish habitat in some areas, increasing the expenditures on fishing licenses. Data analytics and biophysical models can be used to characterize both the supply and demand for ecosystem services, as well as the flows between them (Bagstad et al. 2014;Jager and Efroymson 2018;Schirpke et al. 2019). Because ecosystem services supply different beneficiaries, social data must be spatially alignable with changes in benefitrelevant indicators to assess monetary value (Olander et al. 2018). ...
Chapter
Assessing the sustainability of natural resource management choices for agricultural and forest lands requires quantification of potential changes to a set of environmental and socioeconomic indicators selected to characterize reference scenarios relative to projected future scenarios. Correctly framing the questions with local stakeholders is a critical first step in the sustainability assessment, and the questions that can be addressed are often limited by data availability. Selecting and prioritizing indicators with stakeholders to address their needs and concerns improves the likelihood of investment in monitoring and evaluation of those indicators over time. Computational techniques for analyzing interactions between the selected indicators are inherently affected by the scales and formats of the assembled indicator datasets. Data analytics have the potential to improve understanding of the potential synergies and tradeoffs involved with meeting multiple environmental and socioeconomic goals simultaneously, but timely and appropriate indicator datasets are not always available—even in this new era of “big data.” Continued improvements in data science and data analytics are needed to broaden understanding and acceptance of problems and to provide valuable information for natural resource management. Advances in these areas will enable society to design future landscapes that meet multiple objectives, including the provisioning of agricultural and forest resources along with a variety of ecosystem services (e.g., clean water and healthy soils).
... In addition, they have roots with a range of depths, including deeper roots that can obtain nutrients from deeper soils (Smith et al., 2013). For these reasons, replacing annual crops with perennial biomass crops can improve downstream water quality (Glover, 2005;Jager and Efroymson, 2018), though this approach will have economic limits due to market demands for annual row crops as quantified in USDOE (2016). Development of perennial grain crops is one promising direction (Zhang et al., 2012). ...
Article
Potential economic and environmental benefits of increasing nitrogen-use efficiency (NUE) are widely recognized but scarcely quantified. This study quantifies the effects of increased NUE on 1) the national agricultural economy using a simulation model of US agriculture and 2) regional water quality effects using a biogeochemical model for the Arkansas-White-Red river basin. National economic effects are reported for NUE improvement scenarios of 10%, 20%, 50%, and 100%, whereas regional water quality effects are estimated for a 20% NUE improvement scenario in the Arkansas-White-Red river basin. Simulating a 20% increase in NUE in row crops is shown to reduce N requirements by 1.4 million tonnes y⁻¹ and increase farmer net profits by 1.6% ($743 million) per year by 2026 over the baseline simulation for the same period. For each 10% increase in NUE, annual farm revenues for commodity crops increased over the baseline by approximately $350 million per year by 2026. Changes in crop prices and land-use relative to the baseline were less than 2%. This suggests a net benefit even though fertilizer cost savings can result in increased cultivation of land, i.e., ‘Jevon's paradox’. Results from the biogeochemical model of the Arkansas-White-Red river basin suggest that a 20% increase in NUE corresponds to a 5.72% reduction in nitrate loadings to freshwaters, with higher reductions in agricultural watersheds. The value of these reductions was estimated as $43 ha⁻¹, for a total of $15.3 to 136.7 million yr⁻¹ in avoided water treatment costs. After estimating the social value of increased NUE, we conclude with a discussion of potential strategies to increase efficiency and the research needed to achieve this goal. These include perennialization of the agricultural landscape, genetic crop improvement, targeted fertilizer application, and manipulation of the plant-root microbiome.
... Regardless of whether perennials survive a flood, their deep rooting structures will persist and continue to hold soil. As a result, perennials reduce the loss of soil and nutrient loadings during flood events and improve downstream water quality (Jager and Efroymson 2018). ...
... The put in place of PES schemes has a promising potential in moving feedstock producers towards more sustainable practices, mainly concerning perennial crops. For instance, Jager and Efroymson (2018) found that PES schemes could drive producers in choosing feedstocks according to their resistance or resilience to disturbance, in order to increase reliability in ES provision over time. However, PES schemes still suffer for a lack of clear and consistent normative references (Pan et al., 2017;Mauerhofer, 2018), as well as for other barriers such as the conflictual role of large-scale companies (Chinangwa et al., 2017). ...
Article
Growing non-food crops in marginal lands has been proposed as a solution to avoid land competition with food production. Mapping marginal agricultural lands is therefore fundamental for the sustainable development of rural landscapes. This study proposes a method based on remote sensing data to identify marginal agricultural lands for the production of wood biomass, and analyse potential trade-offs and synergies between the new wood crops, food production, and Ecosystem Services (ES) provided by vegetation. The province of Rovigo (northern Italy) was chosen as a representative case study. Three classes of marginal agricultural lands were mapped through the use of the Soil Adjusted Vegetation Index (SAVI): i) abandoned or unused agricultural lands, ii) potentially poorly or non-managed croplands, and iii) potentially low productivity croplands. Results showed that marginal agricultural lands cover 1.7% of the agricultural areas of the province, and approximately 13,642 MWh yr−1 of Second-Generation (2G) bioenergy can be produced in marginal agricultural areas while enhancing ES provided by vegetation, and avoiding any trade-off with food production. Since this energy potential covers just 8.4% of the total potential authorized in the province, the enhancement of ES could provide a suitable argument to support the conversion of marginal agricultural lands and increase the multifunctionality of the agricultural landscape.
... In some cases, mitigation can also generate income for farmers. For example, three-stage buffers from which perennial grasses, willow and poplar are harvested for biomass energy (Jager and Efroymson, 2018;Maringanti et al., 2011). In order to consider additional impacts of possible management options, it may be useful to include a quantitative analysis of the costs or benefits associated with actions that would serve to implement the possible management scenarios. ...
Article
Assessing and managing risks of anthropogenic activities to ecological systems is necessary to ensure sustained delivery of ecosystem services for future generations. Ecological models provide a means of quantitatively linking measured risk assessment endpoints with protection goals, by integrating potential chemical effects with species life history, ecological interactions, environmental drivers and other potential stressors. Here we demonstrate how an ecosystem modeling approach can be used to quantify insecticide-induced impacts on ecosystem services provided by a lake from toxicity data for organism-level endpoints. We used a publicly available aquatic ecosystem model AQUATOX that integrates environmental fate of chemicals and their impacts on food webs in aquatic environments. By simulating a range of exposure patterns, we illustrated how exposure to a hypothetical insecticide could affect aquatic species populations (e.g., recreational fish abundance) and environmental properties (e.g., water clarity) that would in turn affect delivery of ecosystem services. Different results were observed for different species of fish, thus the decision to manage the use of the insecticide for ecosystem services derived by anglers depends upon the favored species of fish. In our hypothetical shallow reservoir, water clarity was mostly driven by changes in food web dynamics, specifically the presence of zooplankton. In contrast to the complex response by fishing value, water clarity increased with reduced insecticide use, which produced a monotonic increase in value by waders and swimmers. Our study clearly showed the importance of considering nonlinear ecosystem feedbacks where the presence of insecticide changed the modeled food-web dynamics in unexpected ways. Our study highlights one of the main advantages of using ecological models for risk assessment, namely the ability to generalize to meaningful levels of organization and to facilitate quantitative comparisons among alternative scenarios and associated trade-offs among them while explicitly accounting for different groups of beneficiaries.
... Such results are important to consider not only in directly avoiding excessive fertilizer and labor costs for farmers, but also the potential for their follow-on effects of increased nutrient runoff and eutrophication, as well as the potential for increased greenhouse gas effects from soil nitrous oxide emissions. The information obtained by applying this meta-analysis could be used to estimate the value of nutrient credits as the avoided costs of fertilizer application and water treatment [70], thereby bringing the external environmental benefits of perennial biomass crops into the decision-making process, and also allow more informed decisions about where nutrient trading markets can operate to effectively supplement farmer income while promoting sustainable and renewable energy production [71]. However, the studies included in this meta-analysis were exclusively conducted in Europe and the US, so it is hard to rule out the possibility that limited cultivar varieties used and/or geographic conditions investigated might contribute to the similar trends in biomass yield responses to N fertilization. ...
Article
Minimum nitrogen requirement Mean annual temperature Mean annual precipitation Pairwise meta-analyses Regression-based models A B S T R A C T Perennial grasses are touted as sustainable feedstocks for energy production. Such benefits, however, may be offset if excessive nitrogen (N) fertilization leads to economic and environmental issues. Furthermore, as yields respond to changes in climate, nutrient requirements will change, and thus guidance on minimal N inputs is necessary to ensure sustainable bioenergy production. Here, a pairwise meta-analysis was conducted to investigate the effects of N fertilization (amount and duration) and climate on the above-ground biomass yields of miscanthus (Miscanthus x giganteus) and switchgrass (Panicum virgatum L.). Both regression models and meta-analyses showed that switchgrass was more responsive to N than miscanthus, although both showed significant and positive N effects. Meta-analysis further showed that the positive growth response of miscanthus to N application increased with N addition rates of 60-300 kg N ha −1 year −1 , but the magnitude of the response decreased with the number of years of fertilization (duration). N effects on switchgrass biomass increased and peaked at rates of 120-160 kg N ha −1 year −1 and 5-6 years of N inputs, but diminished for rates > 300 kg N ha −1 year −1 and > 7 years. Meta-analysis further revealed that the influences of N on switchgrass increased with both mean annual temperature and precipitation. Miscanthus yields were less responsive to climate than switchgrass yields. This meta-analysis helps fill a gap in estimation of biofeedstock yields based on N fertilization and could help better estimate minimum N requirements and soil management strategies for miscanthus and switchgrass cultivation across climatic conditions, thereby improving the efficiency and sustainability of bioenergy cropping systems.
... In the temperate climate of North America, perennial grasses and short-rotation woody crops (Table A1) require fewer nutrient additions because they translocate nutrients and carbon to extensive root systems during the non-growing season. Reduced nutrient runoff improves habitat for aquatic species by protecting water quality (Jager and Efroymson, 2018). Compared to annual crops, perennials are more tolerant to extreme soil moisture conditions and they have lower irrigation requirements. ...
Article
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The concept of nature as capital is gaining visibility in policies and practices in both the public and private sectors. This change is due to an improved ability to assess and value ecosystem services, as well as to a growing recognition of the potential of an ecosystem services approach to make tradeoffs in decision making more transparent, inform efficient use of resources, enhance resilience and sustainability, and avoid unintended negative consequences of policy actions. Globally, governments, financial institutions, and corporations have begun to incorporate natural capital accounting in their policies and practices. In the United States, universities, nongovernmental organizations, and federal agencies are actively collaborating to develop and apply ecosystem services concepts to further national environmental and economic objectives. Numerous federal agencies have begun incorporating these concepts into land use planning, water resources management, and preparations for, and responses to, climate change. Going forward, well-defined policy direction will be necessary to institutionalize ecosystem services approaches in federal agencies, as well as to guide intersector and interdisciplinary collaborative research and development efforts. In addition, a new generation of decision support tools are needed to further the practical application of ecosystem services principles in policymaking and commercial activities. Improved performance metrics are needed, as are mechanisms to monitor the status of ecosystem services and assess the environmental and economic impacts of policies and programs. A greater national and international financial commitment to advancing ecosystem services and natural capital accounting would likely have broad, long-term economic and environmental benefits.
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Excess nutrients from agriculture in the Mississippi River drainage, USA have degraded water quality in freshwaters and contributed to anoxic conditions in downstream estuaries. Consequently, water quality is a significant concern associated with conversion of lands to bioenergy production. This study focused on the Arkansas-White-Red river basin (AWR), one of five major river basins draining to the Mississippi River. The AWR has a strong precipitation gradient from east to west, and advanced cellulosic feedstocks are projected to become economically feasible within normal-to-wet areas of the region. In this study, we used large-scale watershed modeling to identify areas along this precipitation gradient with potential for improving water quality. We compared simulated water quality in rivers draining projected future landscapes with and without cellulosic-bioenergy for two future years, 2022 and 2030 with an assumed farmgate price of $50 per dry ton. Changes in simulated water quantity and quality under future bioenergy scenarios varied among subbasins and years. Median water yield, nutrient loadings, and sediment yield decreased by 2030. Median concentrations of nutrients also decreased, but suspended sediment, which is influenced by decreased flow and in-stream processes, increased. Spatially, decreased loadings prevailed in the transitional ecotone between 97° and 100° longitude, where switchgrass, Panicum virgatum L., is projected to compete against alternative crops and land uses at $50 per dry ton. We conclude that this region contains areas that hold promise for sustainable bioenergy production in terms of both economic feasibility and water-quality protection. This article is protected by copyright. All rights reserved.
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Water quality and economic models were linked to assess the economic and environmental benefits of implementing a phosphorus credit trading program in an agricultural sub-basin of Lake Okeechobee watershed, Florida, United States. The water quality model determined the effects of rainfall, land use type, and agricultural management practices on the amount of total phosphorus (TP) discharged. TP loadings generated at the farm level, reaching the nearby streams, and attenuated to the sub-basin outlet from all sources within the sub-basin, were estimated at 106.4, 91, and 85 mtons yr(-)(1), respectively. Almost 95% of the TP loadings reaching the nearby streams were attributed to agriculture sources, and only 1.2% originated from urban areas, accounting for a combined TP load of 87.9 mtons yr(-)(1). In order to compare a Least-Cost Abatement approach to a Command-and-Control approach, the most cost effective cap of 30% TP reduction was selected, and the individual allocation was set at a TP load target of 1.6 kg ha(-1) yr(-1) (at the nearby stream level). The Least-Cost Abatement approach generated a potential cost savings of 27% ($1.3 million per year), based on an optimal credit price of $179. Dairies (major buyer), ornamentals, row crops, and sod farms were identified as potential credit buyers, whereas citrus, improved pastures (major seller), and urban areas were identified as potential credit sellers. Almost 81% of the TP credits available for trading were exchanged. The methodology presented here can be adapted to deal with different forms of trading sources, contaminants, or other technologies and management practices.
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This study builds a general equilibrium model of ecosystem services, with sectors of the economy competing for use of the environment. The model recognizes that production processes in the real world require a combination of natural and human inputs, and understanding the value of these inputs and their competing uses is necessary when considering policies of resource conservation. We demonstrate the model with a numerical example of the Mississippi-Atchafalaya river basin, in which grain production in the upper basin causes hypoxia that causes damages to the downstream fishing industry. We show that the size of damages is dependent on both environmental and economic shocks. While the potential damages to fishing are large, most of the damage occurs from economic forces rather than a more intensive use of nitrogen fertilizers. We show that these damages are exacerbated by increases in rainfall, which will likely get worse with climate change. We discuss welfare effects from a tax on nitrogen fertilizers and investments in riparian buffers. A 3% nitrogen tax would reduce the size of the hypoxic zone by 11% at a cost of 2% of Iowa's corn output. In comparison, riparian buffers are likely to be less costly and more popular politically.
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Nitrogen fertilizer and harvest management will alter soils under bioenergy crop production and the long-term effects of harvest timing and residue removal remain relatively unknown. Compared to no-tilled corn (NT-C, Zea mays L.), switchgrass (Panicum virgatum L.) is predicted to improve soil properties [i.e. soil organic C (SOC), soil microbial biomass (SMB-C), and soil aggregation] due to its perennial nature and deep-rooted growth form, but few explicit field comparisons exist. We assessed soil properties over 9 years for a rainfed study of N fertilizer rate (0, 60, 120, and 180 kg N ha−1) and harvest management on switchgrass (harvested in August and postfrost) and NT-C (with and without 50% stover removal) in eastern NE. We measured SOC, aggregate stability, SMB-C, bulk density (BD), pH, P and K in the top 0–30 cm. Both NT-C and switchgrass increased SMB-C, SOC content, and aggregate stability over the 9 years, reflecting improvement from previous conventional management. However, the soils under switchgrass had double the percent aggregate stability, 1.3 times more microbial biomass, and a 5–8% decrease in bulk density in the 0–5 and 5–10 cm depths compared to NT-C. After 9 years, cumulative decrease in available P was significantly greater beneath NT-C (−24.0 kg P ha−1) compared to switchgrass (−5.4 kg P ha−1). When all measured soil parameters were included in the Soil Management Assessment Framework (SMAF), switchgrass improved soil quality index over time (ΔSQI) in all depths. NT-C without residue removal did not affect ΔSQI, but 50% residue removal decreased ΔSQI (0–30 cm) due to reduced aggregate stability and SMB-C. Even with best-management practices such as NT, corn stover removal will have to be carefully managed to prevent soil degradation. Long-term N and harvest management studies that include biological, chemical, and physical soil measurements are necessary to accurately assess bioenergy impacts on soils.
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The high theoretical productivity of microalgae makes it a promising energy crop, but economically viable large-scale production facilities have yet to emerge. Coupling algae cultivation ponds with flue gas emissions from power utilities to provide carbon dioxide and municipal wastewater to provide nutrients has been recommended as a solution. This flue gas and wastewater co-utilization (FWC) strategy not only reduces the upstream impacts and costs associated with providing inputs, but also provides a credit for wastewater treatment, a service currently required to reduce production costs to a viable level. This study provides the first national assessment of the potential for producing algal bio-oil in the United States using FWC. Spatial-temporal algae growth was simulated using solar radiation and temperature data to calculate the average annual algae yield for any location, which significantly impacts feasibility. The results of this model were integrated into a geospatial analysis which establishes the economically viable bio-oil production potential of FWC by accounting for the relative abundance of the input resources and their proximity. At most, 1.7 billion liters of bio-oil could be produced annually in a manner economically competitive with crude oil prices of $80 per barrel. The amount of nutrients in wastewater limits yields to 20.5 L of bio-oil per capita annually, and climatic constraints further reduce this potential by nearly 60%. Carbon dioxide constraints play a negligible role. Although the bio-oil production potential of FWC is relatively small, it does provide an opportunity to increase national biofuel output while providing a needed service.
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Fisheries of enclosed and semi‐enclosed seas provide the first basis for evaluating human impacts on marine ecosystems. These have become of serious concern before similar changes are detectable in oceanic systems, thus emphasizing their value as laboratories for comparative study of man‐induced changes. The paper discusses the relevance of the cline, oligo‐meso‐eu‐dys‐trophic to stressed marine systems, and focuses on impacts on fisheries of enhanced nutrient runoff, noting common features with marine systems subject to natural enrichment, but also with well‐studied freshwater systems. It is suggested that under nutrient enrichment and heavy fishing, both “top down”; and “bottom up”; trophic mechanisms act in synchrony to change the trophic chain, leading initially to increased fishery productivity of formerly oligotrophic systems, followed by more drastic and negative changes as nutrient input passes beyond a state that may be called mesotrophic.
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It is suggested that evolution in plants may be associated with the emergence of three primary strategies, each of which may be identified by reference to a number of characteristics including morphological features, resource allocation, phenology, and response to stress. The competitive strategy prevails in productive, relatively undisturbed vegetation, the stress-tolerant strategy is associated with continuously unproductive conditions, and the ruderal strategy is characteristic of severely disturbed but potentially productive habitats. A triangular model based upon the three strategies may be reconciled with the theory of r- and K-selection, provides an insight into the processes of vegetation succession and dominance, and appears to be capable of extension to fungi and to animals.
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Traits that enable plants to exploit low-resource environments (eg slow tissue turnover, low transpiration rate, high root:shoot ratio, and high concentrations of plant defences against pathogens and herbivores) are physiological linked to key growth-related traits (low rates of photosynthesis, nutrient uptake, and growth). A genetic change in a switch or underlying trait that turns on this stress resistance syndrome (SRS), which causes it to be expressed over a wider range of environmental circumstances, would effectively convert a high-resource genotype into one that is more stress-tolerant. Because of physiological linkages between growth-related traits and the SRS, any heritable change in a key growth-related trait will pleiotropically affect the SRS. Therefore, heritable changes in these key growth-related traits could be accompanied by evolution of the entire SRS. Evidence for this hypothesis comes from single-gene mutants that differ in many stress-related traits, rapid evolution of metal-tolerant populations that are broadly stress-resistant, and consistent patterns of traits in species along gradient in resource availability. Rapid evolution in response to changing environmental stress may allow many short-lived species to respond to human-induced environmental change and provide opportunities to develop stress-resistance crops. However, the time lag between generations of long-lived species that dominate most natural vegetation may not allow mature individuals of these species to keep pace with rapid global change. -from Authors
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1. Exposed riverine sediments are difficult substrata for seedling establishment because of extremes in the microclimate, poor soil conditions and frequent habitat turnover. Various species of willows and poplars (Salicaceae) appear to be particularly successful in colonising such sediments and are often dominant in floodplain habitats throughout the northern temperate zone. 2. In many Salicaceae regeneration seems to be adapted to regular disturbance by flooding. Efficient seed dispersal is achieved by the production of abundant seed in spring and early summer, which are dispersed by air and water. Seeds are short-lived and germinate immediately on moist surfaces. Seedling establishment is only possible if these surfaces stay moist and undisturbed for a sufficient period of time. 3. Larger plants of Salicaceae have exceptional mechanical properties, such as high bending stability, which enable them to withstand moderate floods. If uprooted, washed away or fragmented by more powerful floods these plants re-sprout vigorously. 4. While these life characteristics can be interpreted as adaptations to the floodplain environment, they may also cause a high genetic variability in populations of Salicaceae and predispose Salicaceae to hybridization. Thus, a feed back between adaptive life history characteristics and the evolutionary process is proposed.
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Recent supply shocks in the Gulf of Mexico - including hurricanes, the Deepwater Horizon oil spill, and the seasonal appearance of a large dead zone of low oxygen water (hypoxia) - have raised concerns about the economic viability of the U.S. shrimp fishery. The ability for U.S. shrimpers to mediate supply shocks through increased prices hinges on the degree of market integration, both among shrimp of different sizes classes and between U.S. wild caught shrimp and imported farmed shrimp. We use detailed data on shrimp prices by size class and import prices to conduct a co-integration analysis of market integration in the shrimp industry. We find significant evidence of market integration, suggesting that the law of one price holds for this industry. Hence, in the face of a supply shocks, prices do not rise and instead imports of foreign farmed fish increase.
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Among several candidate perennial taxa, Miscanthus×giganteus has been evaluated and promoted as a promising bioenergy crop. Owing to several limitations, however, of the sterile hybrid, both at the taxon and agronomic production levels, other options need to be explored to not only improve M. ×giganteus, which was originally collected in Japan, but to also consider the development of other members of its genus, including Miscanthus sinensis, as bioenergy crops. Indeed, there is likely much to be learned and applied to Miscanthus as a bioenergy crop from the long history of intensive interaction between humans and M. sinensis in Japan, which in some regions of the country spans several thousand years. Combined with its high amount of genetic variation, stress tolerance, biotic interactions with fauna, and function as a keystone species in diverse grasslands and other ecosystems within its native range, the unique and extensive management of M. sinensis in Japan as a forage grass and building material provides agronomists, agroecologists, and plant breeders with the capability of better understanding this species in terms of potential contribution to bioenergy crop development. Moreover, the studies described in this review may serve as a platform for future research of Miscanthus as a bioenergy crop in other parts of the world.
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This paper advocates consistently defined units of account to measure the contributions of nature to human welfare. We argue that such units have to date not been defined by environmental accounting advocates and that the term “ecosystem services” is too ad hoc to be of practical use in welfare accounting. We propose a definition, rooted in economic principles, of final ecosystem service units. A goal of these units is comparability with the definition of conventional goods and services found in GDP and the other national accounts. We illustrate our definition of ecological units of account with concrete examples. We also argue that these same units of account provide an architecture for environmental performance measurement by governments, conservancies, and environmental markets.
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A zone of hypoxic and anoxic waters has become a dominant feature of the northern Gulf of Mexico. Nitrogen draining into the Gulf from the Mississippi Basin has been identified as the primary source of the problem. Reducing nitrogen loads from point and nonpoint sources in the basin is the primary goal of an action plan developed to address the problem. In this paper, we use data on point source dischargers and a model of the agriculture sector to examine whether the purchase of nitrogen reduction “credits” from nonpoint sources would reduce the cost of nitrogen control if point sources are required to reduce nitrogen discharges. Results indicate that a substantial degree of credit trading could affect agricultural commodity prices, thereby affecting agricultural production outside the basin.
Article
Two primary approaches to perennial biofuel crop production studied so far are fertilized grass monocultures and low-input high-diversity grasslands. While high-yielding perennial grass varieties are being developed in fertilized monocultures, breeding for yield in low-input high-diversity systems would be difficult. Before initiating breeding for low-input systems, it is therefore important to know the minimum number of functional groups and species required for maximum biomass harvest from low-input grasslands. We controlled the number of perennial grassland species in 168 plots in Minnesota, USA. Species were selected at random from a pool of 18, and 1, 2, 4, 8, or 16 were planted in each plot. Aboveground biomass was measured annually, and the plots were burned each spring. We found a strongly positive log-linear relationship between average annual aboveground biomass and planted species number, but a large proportion of plot-to-plot variability remained unexplained. We performed a conditional analysis of the aboveground biomass data to determine whether considering species identity would reduce the minimum number of species necessary in order to achieve yields similar to the highest diversity treatments. A model that accounted for the presence of legumes in general, and for the presence of the legume species Lupinus perennis in particular, showed no increase in biomass yield with increased species number. Over 11 years, average yields of L. perennis/C4 grass bicultures were similar to those of 16-species (maximum diversity) plots, and both were >200% greater than the average of monocultures. Thus, under low-input conditions, the choice of the appropriate few perennial plant species for each location might result in systems with biomass yields similar to those from high-diversity systems. Because breeding biofuel crops in diverse mixtures would introduce complexity that is unwarranted in terms of maximum biomass yield, the first biofuel crop breeding programs for low-input systems are likely to accelerate progress by focusing on grass–legume bicultures.
Article
It is suggested that there are three major determinants of vegetation-competition, stress and disturbance-and that each has invoked a distinct strategy on the part of the flowering plant. A method is described whereby it is possible to distinguish types of herbaceous vegetation by reference to the relative importance of the three strategies in the genotypes of the component species.
Article
While biofuels may yield renewable fuel benefits, there could be downsides in terms of water quality and other environmental stressors, particularly if corn is relied upon exclusively as the feedstock. The consequences of increased corn production will depend importantly on where (and how) the additional corn is grown, which, in turn, depends on the characteristics of land and its associated profitability. Previous work has relied on rules of thumb for allocating land to increased acreage based on historical land use or other heuristics. Here, we advance our understanding of these phenomena by describing a modeling system that links an economics-driven land use model with a watershed-based water quality model for the Upper Mississippi River Basin (UMRB). This modeling system is used to assess the water quality changes due to increased corn acreage, which is associated with higher relative corn prices. We focus on six scenarios based on six realistic pairs of corn and soybean prices which correspond to a scale of decreasing soybean to corn price ratio. These price-driven land use changes provide estimates of the water quality effects that current biofuel policies may have in the UMRB. Our analysis can help evaluate the costs and environmental consequences associated with implementation strategies for the biofuel mandates of the new energy bill. The amounts of total N and P delivered to the outlet of the UMRB (located at Grafton, Illinois, USA) rise as corn production becomes more intensive in the region. Our results indicate that a 14.4% in corn acreage in the watershed due to corn intensification in the most economically profitable locations would result in a 5.4% increase in total nitrogen loads and in a 4.1% increase in total phosphorus loads at Grafton. Our most aggressive scenario, driven by high but not out of reach crop prices, results in about a 57% increase in corn acreage with a corresponding 18.5% increase in N and 12% increase in P. These are somewhat conservative increases in nutrients, compared to those of previous studies, likely due to our focus on cultivated cropland which is already heavily fertilized.
Article
Economic and cultural values, the same forces that led people to alter floodplain ecosystems, will be the forces that determine the extent of their restoration. Landowner investment in agricultural production and forest and hydrologic restoration will reflect perceived economic returns from investments, as well as personal preferences for the environmental services each land use provides. Conservation programs and emerging environmental markets can encourage floodplain restoration, but will be effective only if they improve economic returns from bottomland management relative to other land uses. Over the past three years, prices for corn, soybeans, wheat, and other agricultural commodities have increased sharply, increasing returns to crop production and decreasing the amount of marginally profitable cropland, land most likely to be restored to bottomland hardwoods. Understanding commodity price dynamics is critical for understanding the potential for retiring cropland into bottomlands. Often Farm Bill conservation title provisions attract the greatest attention regarding bottomland hardwood restoration. However, the commodity title, which sets commodity price supports, and energy policy, need to be considered because commodity and energy policy effect returns from bottomland hardwood restoration.