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At least 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

AmeriFlux FLUXNET-1F US-Ne2 Mead - irrigated maize-soybean rotation site

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ne2 Mead - irrigated maize-soybean rotation site. This is the FLUXNET version of the carbon flux data for the site US-Ne2 Mead - irrigated maize-soybean rotation site produced by applying the standard ONEFlux (1F) software. Site Description - The study site is one of three fields (all located within 1.6 km of each other) at the University of Nebraska Eastern Nebraska Research, Extension and Education Center near Mead, Nebraska. This site is irrigated with a center pivot system. Prior to the initiation of the study, the irrigated site had a 10-yr history of maize-soybean rotation under no-till management. A tillage operation (disking) was done just prior to the 2001 planting to homogenize the top 0.1 m of soil, incorporate P and K fertilizers, as well as previously accumulated surface residues. Since this tillage operation, the site has been under no-till management in a maize-soybean rotation (maize odd years and soybean even years). There was a brief period due to an intercomparison study from 2010 to 2013 when fall conservation tillage was performed and maize (not soybean) was planted in 2010 and 2012. The management reverted to a strictly no-till maize-soybean crop rotation after 2014.

Suyker, Andy [University of Nebraska - Lincoln]↗
DOE OSTI2026

AmeriFlux US-ABb Archbold ungrazed seminative pasture

This is the AmeriFlux version of the carbon flux data for the site US-ABb Archbold ungrazed seminative pasture. Site Description - Semi-native pasture used for grazing since the early 1900's. Prescribed fire every 2-3 years. There is no record of any soil amendments of fertilizer applied. Soil is sandy loamy. Malabar serie. Grazing was removed in 2013 for the period of the study 2013-2015.

Bernacchi, Carl [Global Change and Photosynthesis ↗
DOE OSTI2026

AmeriFlux US-ABa Archbold grazed seminative pasture

This is the AmeriFlux version of the carbon flux data for the site US-ABa Archbold grazed seminative pasture. Site Description - Grazing since the early 1900s. Prescribed fire every 2-3 years. There is no record of any soil amendments or fertilizer applied. Soils are sandy loamy. Malabar soil.

Bernacchi, Carl [Global Change and Photosynthesis ↗
DOE OSTI2026

AmeriFlux FLUXNET-1F US-UiD University of Illinois Restored Native Prairie

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-UiD University of Illinois Restored Native Prairie. This is the FLUXNET version of the carbon flux data for the site US-UiD University of Illinois Restored Native Prairie produced by applying the standard ONEFlux (1F) software. Site Description - Site harvested annually with a mower during winters starting 2009. No fertilizer was applied, and not irrigated. Measurements were paused on March 23, 2016 and resumed in June 2024.

Bernacchi, Carl↗
DOE OSTI2026

AmeriFlux FLUXNET-1F US-Ne3 Mead - rainfed maize-soybean rotation site

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ne3 Mead - rainfed maize-soybean rotation site. This is the FLUXNET version of the carbon flux data for the site US-Ne3 Mead - rainfed maize-soybean rotation site produced by applying the standard ONEFlux (1F) software. Site Description - The study site is one of three fields (all located within 1.6 km of each other) at the University of Nebraska Agricultural Research and Development Center near Mead, Nebraska. While the other two sites are equipped with irrigation systems, this site relies on rainfall. A tillage operation (disking) was done just prior to the 2001 planting to homogenize the top 0.1 m of soil, incorporate P and K fertilizers, as well as previously accumulated surface residues. Since initiation of the study in 2001, this site has been under a strictly no-till, maize-soybean rotation (maize odd years and soybean even years).

Suyker, Andy [University of Nebraska - Lincoln]↗
DOE OSTI2026

AmeriFlux FLUXNET-1F US-ABa Archbold grazed seminative pasture

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-ABa Archbold grazed seminative pasture. This is the FLUXNET version of the carbon flux data for the site US-ABa Archbold grazed seminative pasture produced by applying the standard ONEFlux (1F) software. Site Description - Grazing since the early 1900s. Prescribed fire every 2-3 years. There is no record of any soil amendments or fertilizer applied. Soils are sandy loamy. Malabar soil.

Bernacchi, Carl [Global Change and Photosynthesis ↗
DOE OSTI2026

AmeriFlux FLUXNET-1F US-ABb Archbold ungrazed seminative pasture

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-ABb Archbold ungrazed seminative pasture. This is the FLUXNET version of the carbon flux data for the site US-ABb Archbold ungrazed seminative pasture produced by applying the standard ONEFlux (1F) software. Site Description - Semi-native pasture used for grazing since the early 1900's. Prescribed fire every 2-3 years. There is no record of any soil amendments of fertilizer applied. Soil is sandy loamy. Malabar serie. Grazing was removed in 2013 for the period of the study 2013-2015.

Bernacchi, Carl [Global Change and Photosynthesis ↗
DOE OSTI2024

Realizing Ciamician’s Energy Future

Giacomo Ciamician imagined a future sustained only by sunlight, air and water - the Artificial Leaf and Bionic Leaf enable such a future. The Artificial Leaf uses sunlight to split H 2 O to H 2 and O 2 . The Bionic Leaf-C takes the H 2 from the catalysts of the Artificial Leaf and combines it with CO 2 in air to make biomass and liquid fuels at efficiencies that are 10 to 100 times greater than natural photosynthesis. Extending the approach, the Bionic Leaf-N combines the H 2 from the Artificial Leaf with N 2 in the air to make a sustainable fertilizer. Finally, these discoveries of distributed Fischer-Tropsch and Haber-Bosch processes are particularly useful to the underserved of the world, where large infrastructures for fuel and food production do not exist

Nocera, Daniel G.↗
DOE OSTI2022

Photosynthesis in aging perennial and leaf nitrogen

Perennial energy grasses are a fundamental component of the emerging bioeconomy. While their yield dynamics and environmental services are being widely studied, little attention has been given to how the physiological changes associated with perenniality (e.g., nutrient cycling) that underpin yield and environmental services, change as a function of age. Across species, perennial grasses show a photosynthetic decline as a function of stand age, however, the physiological drivers of this age-related decline are poorly understood. In this manuscript we ask: by how much does nitrogen dilution in larger older plants contribute to this photosynthetic decline? Our results support the hypothesis that nitrogen dilution did not limit photosynthesis in mature stands. Compared per unit of area-based leaf nitrogen, photosynthesis of fertilized mature stands was still 26% lower than unfertilized juvenile stands. We hypothesize that the lack of late-season carbohydrate sinks may instead drive the age-related decline in photosynthesis.

Tejera, Mauricio↗
DOE OSTI2015

Global methane and nitrous oxide emissions from terrestrial ecosystems due to multiple environmental changes

Greenhouse gas (GHG)-induced climate change is among the most pressing sustainability challenges facing humanity today, posing serious risks for ecosystem health. Methane (CH 4 ) and nitrous oxide (N 2 O) are the two most important GHGs after carbon dioxide (CO 2 ), but their regional and global budgets are not well known. In this paper, we applied a process-based coupled biogeochemical model to concurrently estimate the magnitude and spatial and temporal patterns of CH 4 and N 2 O fluxes as driven by multiple environmental changes, including climate variability, rising atmospheric CO 2 , increasing nitrogen deposition, tropospheric ozone pollution, land use change, and nitrogen fertilizer use.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale. The causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts. Climate change and anthropogenic modifications to the hydrologic cycle are expected to further increase the extent and severity of wetland salinization. Salinization alters the fundamental physicochemical nature of the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. Increased concentrations of solutes, especially sulfate, alter the biogeochemical cycling of major elements including carbon, nitrogen, phosphorus, sulfur, iron, and silica. The effects of salinization on wetland biogeochemistry typically include decreased inorganic nitrogen removal (with implications for water quality and climate regulation), decreased carbon storage (with implications for climate regulation and wetland accretion), and increased generation of toxic sulfides (with implications for nutrient cycling and the health/functioning of wetland biota). Indeed, increased salt and sulfide concentrations induce physiological stress in wetland biota and ultimately can result in large shifts in wetland communities and their associated ecosystem functions. The productivity and composition of freshwater species assemblages will be highly altered, and there is a high potential for the disruption of existing interspecific interactions. Although there is a wealth of information on how salinization impacts individual ecosystem components, relatively few studies have addressed the complex and often non-linear feedbacks that determine ecosystem-scale responses or considered how wetland salinization will affect landscape-level processes. Although the salinization of wetlands may be unavoidable in many cases, these systems may also prove to be a fertile testing ground for broader ecological theories including (but not limited to): investigations into alternative stable states and tipping points, trophic cascades, disturbance-recovery processes, and the role of historical events and landscape context in driving community response to disturbance.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Coupled Geomechanical Modeling to Assess Cap Rock Integrity and Mechanical Fault Stability: Application to Farnsworth Field Unit Project

Abstract The SWP project is located in a mature waterflood undergoing conversion to CO2-WAG operations in the Farnsworth, Texas, USA. Anthropogenic CO2 is sourced from a fertilizer and an ethanol plant. This work utilizes Farnsworth’s full-field, history-matched, compositional hydrodynamic coupled geomechanical model for assessing the impact of stress changes observed through the history matched field life. Production and injection induced stress changes, fault stability and caprock integrity investigations are performed to project the potential for fault reactivation and the loss of caprock integrity under shear failure. A static mechanical earth model (MEM) was constructed for use in transient coupled geomechanical model based on the existing Southwest Regional Partnership (SWP) geological model. The static MEM inherits the stratigraphic and structural features of the geologic model and incorporates additional overburden, underburden, and sideburden formations required to impose mechanical boundary conditions. Mechanical properties were distributed in the 3D MEM through integration of geophysical logs and 3-dimensional seismic elastic inversion properties using a combination of Bayesian and stochastic interpolation methods. These data are further enhanced by lab derived strength and failure criteria for the caprock interval. Additionally, interpreted faults and other geological features were included as part of the static structural framework to fully represent subsurface hydraulic and mechanical systems and appropriately integrate heterogeneity. Two-way coupling of hydrodynamic flow and geomechanical simulations incorporates the Kozeny-Carman relationship for updating permeability and is history matched through primary, secondary (waterflooding) and tertiary (CO2 WAG) recovery periods before performing a twenty year forecast. Two-way simulations are performed to understand the effective stress perturbations imposed by field operations: water injection and the more recent implementation of WAG. Evaluation of Mohr circles with liquid production and field pressure charts as well as slip tendency and distance to failure metrics indicate that neither our faults or cap rock are critically stressed. This paper presents the results of the Farnsworth initial attempts to integrate the seismic driven 3D MEM into coupled hydrodynamic geomechanical history match simulation workflow.

02 PETROLEUM↗
DOE OSTI2019

Coupled Hydrodynamic-Geomechanical Modelling of CO2-WAG Field Development at Farnsworth Unit: A Case Study

Abstract The SWP project is located in a mature waterflood undergoing conversion to CO2-WAG operations at Farnsworth, Texas, USA. Utilized CO2 is anthropogenic, sourced from a fertilizer and an ethanol plant. Major project goals are optimizing the storage/production balance, ensuring storage permanence, and developing best practices for CCUS. This paper provides a review of work performed toward development of a 3D coupled Mechanical Earth Model (MEM) for use in assessment of caprock integrity, fault reactivation potential, and evaluation of stress dependent permeability in reservoir forecasting. Mechanical property estimates computed from geophysical logs at selected wellbores were integrated with 3D seismic elastic inversion products to create a 3D "static" mechanical property model sharing the same geological framework as the existing reservoir simulation model including 3 major faults. Stresses in the MEM were initialized from wellbore stress estimates and reservoir simulation pore pressures. One way and two way coupled simulations were performed using a compositional hydrodynamic flow model and geomechanical solvers. Coupled simulations were performed on history matched primary, secondary (waterflood), and tertiary (CO2 WAG) recovery periods, as well as an optimized WAG prediction period. These simulations suggest that the field has been operating at conditions which are not conducive to either caprock failure or fault reactivation. Two way coupled simulations were performed in which permeability was periodically updated as a function of volumetric strain using the Kozeny-Carmen porosity-permeability relationship. These simulations illustrate the importance of frequent permeability updating when recovery scenarios result in large pressure changes such as in field re-pressurization through waterflood after a long primary depletion recovery period. Conversely, production forecasting results are less sensitive to permeability update frequency when pressure cycles are short and shallow as in WAG cycles. This paper describes initial work on development of a mechanical earth model for use in assessment of geomechanical risks associated with CCUS operations at FWU. The emphasis of this work is on integration of available geomechanical data for creation of the static mechanical property model. Preliminary coupled hydro-mechanical simulations are presented to illustrate some of the key diagnostic output from coupled simulations which will be used in later work for in depth evaluation of specific risk factors such as induced seismicity and caprock integrity.

02 PETROLEUM↗
DOE OSTI2020

Outdoor Home Gardener Preferences for Environmental Attributes in Gardening Supplies and Use of Ecofriendly Gardening Practices

Home gardeners’ concerns for the environment are expressed both in the ecofriendly gardening practices they use and in environmental attributes they prefer in the gardening products they purchase. This study uses data from a 2018 survey of 601 Tennessee outdoor home gardeners and a multiple indicators multiple causes (MIMIC) model to illustrate how outdoor home gardener demographics, expenditures, information use, and attitudes influence use of ecofriendly gardening practices and preferences for environmental attributes in home gardening supplies. Practices considered include planting pollinator plants, using rainwater collectors, composting, recycling gardening supplies packaging, using organic gardening methods, and use of soil testing. Gardening supply product attributes include decreased need for fertilizer, pesticides, and water; native plant species; organically produced products; and recyclable packaging. The most widely used practice is recycling gardening supplies packaging, and the least used is soil testing. Gardeners with a greater propensity to use the six gardening practices include male, college graduates, who spend relatively more of their income on gardening supplies, and consider themselves as being knowledgeable about environmental issues. The gardening supply product attribute most widely considered as important is decreased need for pesticides, and least widely considered as important are native species and organically produced. Gardeners more likely to prefer the six gardening supply product attributes include older gardeners, who seek other gardeners for information, and who perceived themselves as being knowledgeable about the environment. This same group likes to grow their own food and feels responsibility for protecting the environment for future generations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Impacts of Nitrogen Rate and Landscape Position on Soils and Switchgrass Root Growth Parameters

Core Ideas Nitrogen rate did not affect soil properties for Oklahoma, South Dakota, and Virginia. Landscape position affected soil properties under higher slope. Nitrogen rate affected root N, surface area, and weight for the total profile. Landscape position affected the root C and N. Switchgrass roots can increase C accumulation and reduce risk of N loss in soils. ABSTRACT Switchgrass ( Panicum virgatum L.) has been recognized as a potential bioenergy feedstock, and can positively impact soils and the environment. The experimental sites were established in 2008 at three locations with each in Oklahoma (OK), South Dakota (SD), and Virginia (VA) to assess the impacts of N fertilization rate (N rate; low, 0 kg ha −1 ; high, 112 kg ha −1 ) and landscape position (shoulder, backslope, and footslope) on select soil properties and root growth parameters. Data indicate that N rate did not affect soil bulk density (BD), pH, electrical conductivity (EC), soil organic carbon (SOC), and total nitrogen (TN) for any of five depths. Landscape position impacted some of these properties by depth, depending on location. The N rate influenced root weight (RW), root surface area (RSA), and root total nitrogen (RTN) for the total profile (0–100‐cm depth) depending on local site conditions. The landscape position impacted RW, root total carbon (RTC), and RTN for total profile according to different site conditions. The interactions of landscape position by N rate on switchgrass root parameters were significant. The findings in this study indicate that the root system of switchgrass could improve soils and increase C accumulation and reduce the risk of N loss to benefit the environment.

09 BIOMASS FUELS↗
DOE OSTI2018

Phosphorus Sorption to Aluminum‐based Water Treatment Residuals Reacted with Dairy Wastewater: 2. X‐Ray Absorption Spectroscopy

Phosphorus capture from wastewater can decrease water pollution and provide a P‐rich fertilizer alternative for use in agricultural production. This study was conducted to elucidate P retention mechanisms in Al‐based water treatment residuals (Al‐WTR) to gain insight regarding P sorption and the potential for P release from Al‐WTR after reaction with dairy wastewater. Synchrotron‐based microfocused X‐ray fluorescence (micro‐XRF) spectrometry, bulk P K ‐edge X‐ray absorption near edge structure spectroscopy (XANES), and P K ‐edge micro‐XANES spectroscopy were used to determine P distribution and speciation within the Al‐WTR materials. Bulk XANES analyses indicated a shift from ∼56 P atom % Ca‐associated P in the initial Al‐WTR to ∼32% P atom % Ca‐associated P after reaction with wastewater; Al‐associated P made up the remainder of the P species. According to XANES analyses, adsorption appeared to be the primary P retention mechanism in the Al‐WTR materials. However, micro‐XANES analyses depicted a more complicated picture of P retention mechanisms, with regions of primarily Al‐associated P, regions of primarily Ca‐associated P, regions of mixed Al‐ and Ca‐associated P, and distinct apatite‐ or octocalcium phosphate‐like P grains. Synchrotron micro‐XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al‐WTR aggregates. Organic P species were not explicitly identified via P K ‐edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. Although diffusion and sorption to Al may decrease P bioavailability, Ca‐associated P may increase P bioavailability from Al‐WTR that is reused as a soil amendment. Core Ideas XAS provided unambiguous evidence of P associations with Al and Ca in water treatment residuals. Phosphorus adsorbed to Al and Ca surfaces in Al‐based water treatment residuals. Grains of apatite‐ or octocalcium phosphate‐like P were found in water treatment residuals. Phosphorus diffused into aggregates on reaction with P‐rich wastewater. Evidence from electron microscopy and XRD complemented these findings.

Massey, Michael S.↗
DOE OSTI2019

X‐Ray Spectroscopic Quantification of Struvite and Dittmarite Recovered from Wastewater

Phosphorus recovery from wastewater as struvite (MgNH 4 PO 4 ⋅6H 2 O) or dittmarite (MgNH 4 PO 4 ⋅H 2 O) can decrease water pollution risk, as well as produce a P‐rich material suitable as fertilizer. However, most studies to date have focused on the removal of P from wastewater, rather than on characterization of the recovered P materials. The objective of this work was to apply microfocused X‐ray fluorescence (XRF) spectroscopy, and both bulk and microfused X‐ray absorption near edge structure (XANES) spectroscopy, to provide insight into the speciation of recovered P in various struvite‐containing and struvite‐like materials. Three materials were investigated: homogeneous crystalline struvite on apatite seed, homogeneous dittmarite, and heterogeneous struvite with sand contamination (referred to as the “sandy” material). The struvite materials were recovered from dairy wastewater, whereas the dittmarite was from a cheese processing plant. Phosphorus speciation in the crystalline struvite on apatite seed material was ∼17% apatite and 83% struvite; in the “sandy” material, P was ∼24% apatite and ∼76% struvite, with an uncertainty of approximately ±15%. The P K ‐edge XANES spectra of recovered dittmarite appeared pure. These findings highlight the heterogeneity of recovered P materials and underscore the importance of P speciation to understand P release behavior and bioavailability from recovered phosphates. Core Ideas Multiple methods should be used to corroborate spectroscopic estimates of P speciation. Dittmarite P K ‐edge XANES spectra are distinct from spectra of chemically similar struvite. Phosphorus K ‐edge XANES spectroscopy can quantify Mg‐associated P >15 atom% P.

Massey, Michael S.↗
DOE OSTI2019

Nitrate Leaching from Continuous Corn, Perennial Grasses, and Poplar in the US Midwest

Leaching from annual corn ( Zea mays L.) crops is a primary source of nitrate (NO 3 - ) pollution of ground and surface waters. Here, we compare NO 3 - losses from no-till corn with losses from various alternative perennial cropping systems (switchgrass [ Panicum virgatum L.], miscanthus [ Miscanthus ×giganteus J.M. Greef & Deuter ex Hodkinson & Renvoiz], a native grass mixture, and restored prairie), as well as hybrid poplar ( Populus nigra L. × P. maximowiczii A. Henry ‘NM6’), all grown on a well-drained soil in Michigan. Soil water was sampled from below the root zone using suction cup samplers during nonfrozen periods (March–November) between 2009 and 2016. Leaching was estimated from NO 3 - concentrations in soil water and modeled drainage (percolation) rates. Drainage rates were not significantly different among crops, constituting ~30% of total annual precipitation. Aboveground net primary production (Mg ha -1 yr -1 ) averaged across the 7 yr was highest in poplar (30.8 ± 1.9 [SE]) followed by miscanthus (23.9 ± 2.4) and corn (20.4 ± 0.9). Volume-weighted mean NO 3 - concentrations (mg N L -1 ) and NO 3 - leaching (kg ha -1 yr -1 ) averaged across the 7 yr were 9.2 and 34.1, 2.3 and 5.9, and 3.0 and 7.2, respectively, for corn, perennial grasses and poplar. Approximately 10 to 32% of applied N was lost as NO 3 - from these crops, with the highest percent losses from poplar (32%) followed by corn (20%). Perennial cropping systems leached considerably more NO 3 - in first few years after planting, but over 7 yr they lost much less NO 3 - than corn. Perennial crops may therefore help ameliorate NO 3 - pollution in agricultural landscapes even if they receive modest N fertilization.

54 ENVIRONMENTAL SCIENCES↗