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At least 55 records · Page 3
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DOE OSTI2022

Significance of application timing, formulation, and cytochrome P450 genotypic class on sweet corn response to dicamba

Sweet corn (Zea mays L.) tolerance to dicamba and several other herbicides is due to cytochrome P450 (CYP)-mediated metabolism and is conferred by a single gene (Nsf1). Tolerance varies by CYP genotypic class, with hybrids homozygous for functional CYP (Nsf1Nsf1) being the most tolerant and hybrids homozygous for mutant CYP alleles (nsf1nsf1) being the least tolerant. The herbicide safener cyprosulfamide (CSA) increases tolerance to dicamba by stimulating the expression of several CYPs. However, the extent to which CSA improves the tolerance of different sweet corn CYP genotypic classes to dicamba is poorly understood. Additionally, the effect of growth stage on sweet corn sensitivity to dicamba is inadequately described. The objective of this work was to quantify the significance of application timing, formulation, and CYP genotypic class on sweet corn response to dicamba. Hybrids representing each of the three CYP genotypes (Nsf1Nsf1, Nsf1nsf1, nsf1nsf1), were treated with dicamba or dicamba + CSA at one of three growth stages: V3, V6, or V9. Across all timings, the nsf1nsf1 hybrid was the least tolerant to dicamba, displaying 16% higher crop injury levels 2 wk after treatment and 2,130 kg ha -1 lower ear mass yields compared with the Nsf1Nsf1 hybrid. The V9 growth stage was the most susceptible time for dicamba injury regardless of genotypic class, with 1.89 and 1,750 kg ha -1 lower ear mass yields compared with the V3 and V6 application timings, respectively. The addition of CSA to dicamba V9 applications reduced the injury from dicamba for all three genotypic classes; however, it did not eliminate the injury. The use of Nsf1Nsf1 or Nsf1nsf1 sweet corn hybrids along with herbicide safeners will reduce the frequency and severity of injury from dicamba and other CYP-metabolized herbicides.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Water use and radiation balance of miscanthus and corn on marginal land in the coastal plain region of North Carolina

Abstract Miscanthus is a perennial grass that can yield substantial amounts of biomass in land areas considered marginal. In the Coastal Plain region of North Carolina, marginal lands are typically located in coarse‐textured soils with low nutrient retention and water‐holding capacity, and high erosivity potential. Little is known about miscanthus water use under these conditions. We conducted a study to better understand the efficiency with which miscanthus uses natural resources such as water and radiant energy to produce harvestable dry biomass in comparison to corn, a typical commodity crop grown in the region. We hypothesized that under non‐limiting soil water conditions, miscanthus would have greater available energy and water use rates owing to its greater leaf area, thus leading to greater agronomic yields. Conversely, these effects would be negated under drought conditions. Our measurements showed that miscanthus intercepted more radiant energy than corn, which led to greater albedo (by 0.05), lower net radiation (by 4% or 0.4 MJ m −2 day −1 ), and lower soil heat flux (by 69% or 1.0 MJ m −2 day −1 ) than corn on average. Consequently, miscanthus had greater available energy (by 7% or 0.6 MJ m −2 day −1 ) and water use rates (by 14% or 0.5 mm day −1 ) than corn throughout the growing season on average, which partially confirmed our hypothesis. Greater water use rates and radiation interception by miscanthus did not translate to greater water‐use (1.5 g kg −1 vs. 1.6 g kg −1 ) and radiation‐use (0.9 g MJ −1 vs. 1.1 g MJ −1 ) efficiencies than corn. Compared to literature values, our data indicated that water and radiation availability were not limiting at our study site. Thus, it is likely that marginal land features present at the Coastal Plain region such as low soil fertility and high air temperatures throughout the growing season may constrain agronomic yields even if soil water and radiant energy are non‐limiting.

Carvalho, Henrique D. R.↗
DOE OSTI2022

AmeriFlux FLUXNET-1F US-Bi2 Bouldin Island corn

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Bi2 Bouldin Island corn. This is the FLUXNET version of the carbon flux data for the site US-Bi2 Bouldin Island corn produced by applying the standard ONEFlux (1F) software. Site Description - Corn field on Bouldin Island in the Sacramento San Joaquin Delta. This site has deep peat that was drained for farming. Over the past 100 years there has been excessive subsidence of the peat in the Delta region. The corn is usually harvested for silage cattle feed. Corn was planted in the field 2017-2023. Sorghum was planted in the field 2024.

Rey-Sanchez, Camilo↗
DOE OSTI2023

How does pelleting alter the enzymatic digestibility of corn stover?

Pelleting of lignocellulosic biomass facilitates its transportation, storage and handling and offers opportunities to improve the enzymatic digestibility of pelleted biomass. Here, we report the impact of pelleting on the enzymatic digestibility of corn stover prior to pretreatment and associated substrate characteristics. Pelleting almost doubles the digestibility of unpretreated corn stover, from 8.2 to 15.5% glucan conversion, at 5% solid loading using 1 FPU Cellic CTec2 per g solids. Compositional analysis indicates that loose and pelleted corn stover have similar non-dissolvable compositions, although their extractives are slightly different. Enzymatic hydrolysis of washed corn stover after size reduction to normalize particle sizes and removal of extractives confirms that pelleting improves corn stover digestibility. Such differences may be explained by the decreased particle size, increased specific surface area, improved cellulose accessibility, and reduction of the polymer length of cellulose induced by pelleting. These findings help to design processing schemes for sustainable and efficient use of lignocellulose.

Chen, Xueli↗
DOE OSTI2023

Challenges and Advances in Aqueous Processing of Corn Stover Pellets into High Concentration Slurries

Significant progress has occurred in developing combined enzyme hydrolysis and fermentation technologies for transforming lignocellulosic feedstocks into ethanol and other bioproducts. Various routes described in the literature show that low carbon footprint processes efficiently convert the cellulose and hemicellulose fractions of pretreated corn stover, wood chips, and sugarcane bagasse to sugars and to ethanol.Combinations of different pretreatments at high or low pH or in liquid hot water, followed by enzyme hydrolysis and fermentation or direct conversion of cellulose to ethanol (i.e., by consolidated bioprocessing)have been demonstrated. These successes have brought the need to preparing the feedstock – before it enters the biorefinery – into focus. This paper summarizes recent developments in liquefying corn stover,before pretreatment, so that slurries with yield stresses below 200 Pa are obtained and a “pumpable” corn stover slurry results at initial solids loadings of up to 300 g/L. The manner in which corn stover pellets are combined with water and enzyme in an agitated bioreactor is described, and properties that define slurry behavior are presented. Implications on biorefinery operations are explained in terms of particle properties and the preprocessing of corn stover as well as the team approach used to obtain these results.

Wassgren, Carl↗
DOE OSTI2022

High Solids Loading Aqueous Slurry Formation of Corn Stover Before Pretreatment in a Fed-batch Bioreactor

With the increase on population the world will depend on renewable sources to meet the increasingly energy needs. Use of lignocellulosic biomass as a renewable source has been proven efficient for conversion to cellulosic ethanol and capable of contributing to achieve the threshold on energy demand while reducing greenhouse gases in 90% when compared with fossil fuels (Wang et al., 2007, 2012). However, the processing of biomass encounters limitations in feeding and flow within biorefineries due to the system plugging by compaction and slurry high yield stress, preventing transport of biomass materials and in some cases unexpected plant shutdowns that results in high operational costs (dos Santos et al., 2021; Ximenes et al., 2021). Different solutions for biomass handling and slurry formation from densified materials like pellets have been studied. Cellulosic biomass residues are typically processed in pretreatment reactors to which acid or base is added (Humbird et al., 2002). Other pretreatments such as liquid hot water (LHW) and steam explosion that act without the addition of chemicals use pressures above the saturation vapor of water, to disrupt biomass structure (Ruiz et al., 2021). Although these methods are widely known, the use of pretreatments like acid digestion and LHW present challenges like waste disposal and could be energy inefficient (Mosier et al., 2005). Alternatively other approaches like enzymatic liquefaction have been applied for biomass transformation into slurries with promising results and without the use of pretreatments (dos Santos et al., 2021). Nevertheless, enzymatic liquefaction implementation faces difficulties due to the recalcitrant properties of biomass, its variability, and the release of enzyme inhibitors. While it has been proven that chemical composition properties in biomass have effects on enzyme inhibition (Huang et al., 2022; Kim et al., 2011; Zhai et al., 2018), hindering the efficiency of the liquefaction, not ample research has been conducted in understanding the physical properties as particle size, porosity, water adsorption retention and their effect in the ability to form a slurry at high solids concentration (Yan et al., 2020). In order to improve lignocellulosic biomass handling and formation of biomass slurries, enzyme assisted liquefaction for slurry creation from corn stover at solids loadings up to 30% is reported in this work. Two different kinds of biomass (pelleted corn stover and cobs) were liquefied in a fed-batch process using commercial enzymes Celluclast 1.5L or Ctec-2 at 1FPU or 3 FPU per gram of dry solids in 10 mM sodium citrate buffer solution (pH 4.8). Pellets were fed into a 1 L stirred bioreactor according to a predefined fed-batch protocol over the first 5 hours until reaching 30% of solids loading. After 6, 24 and 96 hours, samples were taken and characterized with respect to their sugar composition, rheology and water absorption. Successful slurry creation with dramatically reduced yield stress was achieved for corn stover for both assessed enzymes. Yield stresses of 178±7 Pa (3 FPU, Celluclast 1.5L) and 79±6 Pa (3 FPU, Ctec-2) were measured for corn stover at 24 hours, compared to 6,000 Pa for samples without enzyme. Yield stress was 155± 29 Pa (3FPU, Ctec-2) and 257 ± 72 Pa (1 FPU, Celluclast 1.5L) for corn cobs at 24 hours. Yield stress decreased when residence time increased with an enhanced fluidity noted for higher enzyme concentrations. A profile for 6, 24 and 96h of yield stress measurements is presented.

Gutierrez, Diana↗
DOE OSTI2023

High-moisture pelleting of corn stover using pilot- and commercial-scale systems: Impact of moisture content, L / D ratio and hammer mill screen size on pellet quality and energy consumption

Here, high-moisture pelleting of corn stover was tested in pilot- and commercial-scale systems. For the pilot-scale study, a 6.35 mm screen size hammer mill ground corn stover was reconditioned to moisture between 14 and 29.6% (w.b.), and 5, 7 and 9 L/D ratio pellet die were used. At 29% corn stover moisture content and L/D ratios of 5 and 9, the bulk density and durability of the pellets were ≤450 kg/m 3 and <90% and >540 kg/m 3 and >90%, respectively. Increasing the feedstock moisture and L/D ratio increased the pelleting energy. Increasing the hammer mill screen size to 11.11 mm reduced the bulk density but not the durability. The response surface models adequately described the pelleting process (R 2 ≥ 0.88), and analysis of variance showed a strong interaction between the process variables and pellet properties. Commercial-scale testing of high-moisture pelleting using 6.35 mm ground corn stover bales in the moisture range 24–26% (w.b.) produced pellets with a density of >675 kg/m 3 and durability of >98%, whereas increasing the hammer mill screen size to 11.11 mm reduced the bulk density by about 100 kg/m 3 but not the durability. The energy consumption of the commercial-scale unit operations for the high-moisture pelleting process was in the range 98–124 kW h/ton, which is 64–72% less energy than conventional pelleting that requires energy about 350 kW h/ton for biomass drying from 30% (w.b.) to 10% (w.b.) moisture content before pelleting. Pellets produced using high-moisture pelleting met International Organization for Standardization and Pellets Fuel Institute international standards. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

09 BIOMASS FUELS↗
DOE OSTI2020

A Process for Converting Corn Bran to Furfural without Mineral Acids

Furfural is a bio-derived industrial chemical that has been identified as a platform chemical for the production of renewable fuels and chemicals. Currently, domestic feedstock and processing costs are high, so United States-based furfural production is not competative on the global market. Furthermore, furfural production costs must be much less than the current market price if it is to be competative platform for bio fuels and chemicals. An alternative low-cost feedstock for furfural is corn bran from a corn ethanol process. We have proposed a new process for producing furfural from corn bran that consumes no mineral acids. The high hemicellulose content of corn bran reduces capital and operating costs. Eliminating mineral acids reduces chemical consumption and makes the residual solids suitable for consumption as animal feed. The combination of a low cost source of hemicellulose and high valued residue could make the proposed process more economical than current processes based on corncobs.

09 BIOMASS FUELS↗
DOE OSTI2023

Techno-Economic Case Study: Low-Temperature Conversion Performance Based on Isolated Anatomical Fractions of Corn Stover

This report summarizes analysis conducted to support a case study under the Feedstock-Conversion Interface Consortium (FCIC) focused on techno-economic analysis (TEA) modeling to quantify the yield and cost ramifications for processing isolated anatomical fractions of corn stover through a low-temperature conversion (biochemical pathway) biorefinery. It is hypothesized that different individual anatomical fractions of corn stover vary in composition and recalcitrance, such that processing each fraction on its own e.g. through dedicated campaigns may enable economic benefits relative to processing the whole stover material. To investigate this concept, we worked with FCIC researchers to obtain data on compositional analysis, as well as processing conditions and yields, for conversion of whole corn stover plus three individual anatomical fractions (cobs, husks, and stalks) across key steps of the biorefinery conversion process within FCIC research scope, namely pretreatment and enzymatic hydrolysis. After running the data through the TEA models, fractionated cobs and husks achieved higher fuel yields and lower minimum fuel selling prices than whole corn stover, but stalks fared worse than whole stover on both metrics. The most direct takeaway from this assessment is that a biorefinery would stand to benefit economically from maximizing the use of cob and husk fractions while avoiding or minimizing the use of stalks, though recognizing practical constraints with this approach in maintaining an equivalent processing capacity (fixed at 2,000 dry metric tonne per day in all cases).

09 BIOMASS FUELS↗
DOE OSTI2024

Cellulose molecular weight of corn stover with cotreatment

Here we present a dataset of cellulose molecular weights from corn stover after a cotreatment process. The corn stover sample was subjected to a combination of mechanical disruption (ball milling) and consolidated bioprocessing (CBP) process using the bacterium C. thermocellum at 60 grams/L solids loadings. Cellulose was isolated from control, no cotreatment control, and cotreatment corn stover. Cellulose was then derivatized using anhydrous pyridine and phenyl isocyanate over 48 h at 70 ºC. The reaction was quenched by anhydrous methanol. Methanol and water mixture (7:3, v/v) was added dropwise to promote precipitation of the cellulose derivative. The solids were collected by filtration and thoroughly washed with the methanol and water mixture followed by water. The cellulose derivative was dried overnight under vacuum at 40°C. The obtained cellulose tricarbanilates was then dissolved in tetrahydrofuran (THF) at 1.0 mg/mL and the solution was filtered through a 0.45 µm PTFE filter and placed in an auto-sampler vial. The molecular weight of cellulose was measured by Agilent GPC SECurity 1200 system equipped with four Waters Styragel columns (i.e., HR0.5, HR2, HR4, and HR6) and a UV detector (270 nm). THF was used as the mobile phase. Data collection and processing was performed by Polymer Standards Service WinGPC Unity software (Build 6807). The molecular weight was calculated relative to the polystyrene calibration curve. The data on molecular weights provided information about the effects of cotreatment on corn stover cellulose molecular changes.

Cellulose, molecular weights, corn stover, cotreat↗
DOE OSTI2020

Irrigation, carbon amelioration, nitrogen, and stover removal effects on continuous corn

Corn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a potential feedstock for cellulosic biofuels. Limited information is available on corn stover removal effects on grain yield under different irrigation rates, nitrogen (N) fertilizer rates, and practices to maintain soil carbon (C) and minimize soil erosion. Here, we evaluated potential interactions between irrigation rate (full or limited), C amelioration practices (cover crop, surface-applied manure, or no amelioration practice), fertilizer N management (125 or 200 kg N ha –1 ), and stover removal (residue removal or no residue removal), on no-till continuous corn grain yield located on a silt loam soil in south-central Nebraska (2011–2018). Stover removal increased (P = .0017) grain yield by 1.02 Mg ha –1 and grain N uptake compared with no stover removal. Manure increased corn grain yield by 899 kg ha –1 compared to either the control or cover crop with stover removal while C amelioration practices did not affect grain yield under stover retention. Grain N concentration was higher (P < .0001) with stover removal (13.2 g kg –1 ) than residue retained (12.7 g kg –1 ). Partial factor productivity (grain yield/N rate) was highest for manure treatments with residue removal. The farmgate N balance (N applied – N removed) from stover removal was negative, yet grain yield was not affected after eight growing seasons. Grain yield increased with stover removal and manure application resulting in a cost-effective C amelioration practice whereas incorporating a winter cover crop resulted in similar grain yield as the control.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Long‐term changes in soil carbon and nitrogen fractions in switchgrass, native grasses, and no‐till corn bioenergy production systems

Cellulosic bioenergy is a primary land-based climate mitigation strategy, with soil carbon (C) storage and nitrogen (N) conservation as important mitigation elements. Here, we present 13 years of soil C and N change under three cellulosic cropping systems: monoculture switchgrass (Panicum virgatum L.), a five native grasses polyculture, and no-till corn (Zea mays L.). Soil C and N fractions were measured four times over 12 years. Bulk soil C in the 0–25 cm depth at the end of the study period ranged from 28.4 (± 1.4 se) Mg C ha −1 in no-till corn, to 30.8 (± 1.4) Mg C ha −1 in switchgrass, and to 34.8 (± 1.4) Mg C ha −1 in native grasses. Mineral-associated organic matter (MAOM) ranged from 60% to 90% and particulate organic matter (POM) from 10% to 40% of total soil C. Over 12 years, total C as well as both C fractions persisted under no-till corn and switchgrass and increased under native grasses. In contrast, POM N stocks decreased 33% to 45% across systems, whereas MAOM N decreased only in no-till corn and by less than 13%. Declining POM N stocks likely reflect pre-establishment land use, which included alfalfa and manure in earlier rotations. Root production and large soil aggregate formation explained 69% (p < 0.001) and 36% (p = 0.024) of total soil C change, respectively, and 60% (p = 0.020) and 41% (p = 0.023) of soil N change, demonstrating the importance of belowground productivity and soil aggregates for producing and protecting soil C and conserving soil N. Differences between switchgrass and native grasses also indicate a dependence on plant diversity. Soil C and N benefits of bioenergy crops depend strongly on root productivity and pre-establishment land use.

09 BIOMASS FUELS↗
DOE OSTI2022

Attributing differences of solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationships between two C4 crops: corn and miscanthus

There remains limited information to characterize the solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationship in C4 cropping systems. The annual C4 crop corn and perennial C4 crop miscanthus differ in phenology, canopy structure and leaf physiology. Investigating the SIF-GPP relationships in these species could deepen our understanding of SIF-GPP relationships within C4 crops. Using in situ canopy SIF and GPP measurements for both species along with leaf-level measurements, we found considerable differences in the SIF-GPP relationships between corn and miscanthus, with a stronger SIF-GPP relationship and higher slope of SIF-GPP observed in corn compared to miscanthus. These differences were mainly caused by leaf physiology. For miscanthus, high non-photochemical quenching (NPQ) under high light, temperature and water vapor deficit (VPD) conditions caused a large decline of fluorescence yield (Φ F ), which further led to a SIF midday depression and weakened the SIF-GPP relationship. The larger slope in corn than miscanthus was mainly due to its higher GPP in mid-summer, largely attributed to the higher leaf photosynthesis and less NPQ. Furthermore, our results demonstrated variation of the SIF-GPP relationship within C4 crops and highlighted the importance of leaf physiology in determining canopy SIF behaviors and SIF-GPP relationships.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Timing and extent of crop damage by wild pigs (Sus scrofa Linnaeus) to corn and peanut fields

The global expansion of wild pigs over the last few decades has resulted in an increase in extent and distribution of damages to crops, placing a growing strain on agricultural producers and land managers. Despite the extent of wild pig damage to agriculture, there is little data regarding timing and spatial variability of damage to corn (Zea mays Linnaeus) and we found no data regarding the effect of these factors on peanuts (Arachis hypogaea Linnaeus). Our objective was to determine the timing and extent of wild pig damage to corn and peanut fields, as well as the extent to which local habitat attributes are useful predictors of damage to these crops. During 2017–2018 we performed ground-based surveys throughout the growing season for 29 corn and 41 peanut fields in South Carolina, USA to determine the most important growth stages for wild pig depredation in both crops. Damage to corn peaked shortly after planting during the seedling stage, fell to nearly zero during V4–V6 stages, and resumed during the silk and mature stages. Peanut damage was almost exclusively limited to the seedling stage. Landscape models for both crops identified the extent of forested and wetland areas surrounding crop fields as the most important attributes positively associated with wild pig damage, while the amount of adjacent agricultural area and paved roads were associated negatively. The number of wild pigs identified by remote cameras also was an important indicator of the extent of damage to peanut fields. Results suggest management efforts to limit crop depredation by wild pigs should be targeted shortly prior to planting. Further, because damage was positively associated with the availability of wetland and forest habitats, our results suggest agricultural damage by wild pigs may be most severe near areas of preferred native habitats.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Microwave-assisted catalytic gasification of mixed plastics and corn stover for low tar, hydrogen-rich syngas production

The challenge for efficient management of post-consumer plastic and biomass waste has grown over the past few decades due to their dramatic increases. In comparison to conventional gasification, microwave-assisted co-gasification of plastics and corn stover offers many benefits, including increased H 2 yield and gas components compared to unfavorable char/tar. Nonetheless, for future commercialization of the process and ease of product separation, further reduction of the undesirable tar is necessary, which can be achieved over the catalytic route. Here, in this work, we studied the catalytic effect of magnetite for microwave-assisted co-gasification of corn stover and plastic to make syngas with higher H 2 and lower tar selectivity over non-catalytic conditions. A 1:1:1 ratio of plastic-corn stover-magnetite was used to evaluate the reaction parameters such as temperature, space velocity, heating media, and catalytic cycles under gasification conditions. In comparison with the microwave non-catalytic route, a 100% increase in the total H 2 yield with 76% higher H 2 production efficiency (mmol/kWh) was achieved in the presence of the magnetite catalyst, while reducing the overall tar formation from 9% to 2%. When magnetite was reduced in situ during the reaction, it coupled with microwave and delivered oxygen radicals that cracked down plastic and corn stover intermediates generated from the synergistic effect under microwave heating. Soon after the oxygen transfer process initiated, magnetite reached its final oxidation state consisting of microwave-active Fe and Fe 3 C phases that continued coupling with microwaves along with the generated graphitic carbon to maintain the heat necessary to further reduce the generated tar and make additional gaseous products, as confirmed by XRD, Raman, and TGA analyses.

08 HYDROGEN↗
DOE OSTI2020

Development of a thermophilic coculture for corn fiber conversion to ethanol

Abstract The fiber in corn kernels, currently unutilized in the corn to ethanol process, represents an opportunity for introduction of cellulose conversion technology. We report here that Clostridium thermocellum can solubilize over 90% of the carbohydrate in autoclaved corn fiber, including its hemicellulose component glucuronoarabinoxylan (GAX). However, Thermoanaerobacterium thermosaccharolyticum or several other described hemicellulose-fermenting thermophilic bacteria can only partially utilize this GAX. We describe the isolation of a previously undescribed organism, Herbinix spp . strain LL1355, from a thermophilic microbiome that can consume 85% of the recalcitrant GAX. We sequence its genome, and based on structural analysis of the GAX, identify six enzymes that hydrolyze GAX linkages. Combinations of up to four enzymes are successfully expressed in T. thermosaccharolyticum . Supplementation with these enzymes allows T. thermosaccharolyticum to consume 78% of the GAX compared to 53% by the parent strain and increases ethanol yield from corn fiber by 24%.

09 BIOMASS FUELS↗
DOE OSTI2026

Corn and Switchgrass Derived Sustainable Aviation Fuel Carbon Intensity

The production and use of sustainable aviation fuel (SAF) could lower aviation's carbon footprint. Feedstock agricultural management can optimize—or potentially determine—SAF sustainability and profitability, but long-term SAF feedstock comparisons are limited. Life cycle assessments (LCA) are commonly used to estimate the carbon intensity of producing SAF from emerging feedstocks due to the limited availability of long-term, primary field data. We quantified the agricultural phase and well-to-wake (WTWa) carbon intensities of producing SAF from no-till, continuous corn (Zea mays L.) under 120 kg N ha−1 year−1 (120 N corn) and switchgrass (Panicum virgatum L.) under 60 or 120 kg N ha−1 year−1 (60 N and 120 N SWG, respectively) via LCAs based on measured data from a long-term (1998-present) field experiment on marginally productive cropland located in Eastern NE, USA. Measured data included crop productivity, long-term changes in soil organic carbon (SOC) stocks (0–150 cm), annual soil N2O emissions, and field management practices. Both 120 N corn (2078 L ha−1) and 120 N SWG (1752 L ha−1) produced more SAF than 60 N SWG (1229 L ha−1) (p < 0.0001). However, making SAF from corn had greater life cycle GHG emissions (i.e., WTWa carbon intensity) than making SAF from 120 N and 60 N SWG (61.5 > −14.5 and −27.5 g CO2e MJ−1 SAF, respectively; p = 0.0007), primarily due to SOC accrual during crop production. Here, we demonstrate that agricultural management (e.g., crop type, fertilizer use) can determine the sustainably and productivity of producing SAF by using long-term, measured field data in LCAs.

carbon intensity↗
DOE OSTI2023

Co-Harvest and Anaerobic Co-Storage of Corn Grain and Stover as Biomass Feedstocks

This research investigated the utility of co-harvesting and anaerobic co-storage of corn grain and stover to positively influence their physical and chemical characteristics as a biomass feedstock. Corn grain and stover were harvested in 2019 and 2020 with a self-propelled forage harvester. Stover yield, moisture content, and composition were altered by the harvest date, stubble height, and header configuration. Harvest date had the utility of varying the stover moisture content (p < 0.001) from 42.3% to 53.5% (w.b.) and 43.1% to 53.9% (w.b.) for the 2019 and 2020 harvest years, respectively. Stubble height was also utilized to vary stover moisture content. A negative linear relationship was established between stubble height and stover moisture content for the early (R2 = 0.76) and late harvest (R2 = 0.91) dates for both years. Stover yield also showed a negative linear relationship (R2 = 0.76) with stubble height over both years. Regardless of the stubble height, the row-crop header collected more stover (p < 0.001) than the ear-snapper header. In 2020, harvested stover ranged from 5.0 to 10.5 Mg ha-1, with ha-1 representing 41% to 85% of the total available stover. In both years, stover ash content was less than 64 g kg-1. Material stored in pilot-scale silos (19 L) was well conserved during anaerobic storage, with average DM losses of 4.8% and 3.4% in 2019 and 2020, respectively. Grain moisture content averaged 23.6% (w.b.) at harvest, and 31.0% (w.b.) after storage as moisture migrated from the moist stover to the drier grain. Harvesting whole-plant corn with a forage harvester had the unwanted effect of reducing the particle size of the grain fraction, which would complicate downstream utilization. However, reducing the harvester cutterhead speed increased the fraction of intact kernels from 47% to 85% by mass. The studied system was a viable alternative to conventional corn grain and stover systems for producing feedstocks for biochemical conversion.

09 BIOMASS FUELS↗