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Looking for new alternative raw materials is one of the key issues in line with a bioeconomy approach, particularly for particleboard manufacturing. In this framework, this paper presents a comparison of some physico-mechanical properties and the formaldehyde contents of particleboards made with 30% substitution of grass biomass from six perennial grass species. Our studies indicate relatively high values of mechanical properties for particleboards made with the addition of biomass from grasses with the C4 photosynthetic pathway: Miscanthus x giganteus and switchgrass (Panicum virgatum). Boards made with the addition of biomass from grasses with the C3 photosynthetic pathway—tall wheatgrass (Elymus elongatus), tall fescue (Festuca arundinacea), and perennial ryegrass (Lolium perenne)—gave lower values of mechanical properties. The opposite results were obtained in the case of the formaldehyde content: the lowest value was measured for particleboards made with the addition of tall fescue biomass (0.1% less than the control), and the highest for switchgrass (0.9% greater than the control) and cordgrass (3.2% greater than the control). Future research should address the optimization of the manufacturing process of particleboards from perennial grasses, taking into account the needs and technical possibilities of the wood industry sector. [ABSTRACT FROM AUTHOR]

Abstract: Current knowledge of yield potential and best agronomic management practices for perennial bioenergy grasses is primarily derived from small‐scale and short‐term studies, yet these studies inform policy at the national scale. In an effort to learn more about how bioenergy grasses perform across multiple locations and years, the U.S. Department of Energy (US DOE)/Sun Grant Initiative Regional Feedstock Partnership was initiated in 2008. The objectives of the Feedstock Partnership were to (1) provide a wide range of information for feedstock selection (species choice) and management practice options for a variety of regions and (2) develop national maps of potential feedstock yield for each of the herbaceous species evaluated. The Feedstock Partnership expands our previous understanding of the bioenergy potential of switchgrass, Miscanthus, sorghum, energycane, and prairie mixtures on Conservation Reserve Program land by conducting long‐term, replicated trials of each species at diverse environments in the U.S. Trials were initiated between 2008 and 2010 and completed between 2012 and 2015 depending on species. Field‐scale plots were utilized for switchgrass and Conservation Reserve Program trials to use traditional agricultural machinery. This is important as we know that the smaller scale studies often overestimated yield potential of some of these species. Insufficient vegetative propagules of energycane and Miscanthus prohibited farm‐scale trials of these species. The Feedstock Partnership studies also confirmed that environmental differences across years and across sites had a large impact on biomass production. Nitrogen application had variable effects across feedstocks, but some nitrogen fertilizer generally had a positive effect. National yield potential maps were developed using PRISM‐ELM for each species in the Feedstock Partnership. This manuscript, with the accompanying supplemental data, will be useful in making decisions about feedstock selection as well as agronomic practices across a wide region of the country. [ABSTRACT FROM AUTHOR]

Within-field spatial variability reduces growers’ return on investment and overall productivity while potentially increasing negative environmental impacts through increased soil erosion, nutrient runoff, and leaching. The hypothesis that integrating energy crops into non-profitable segments of agricultural fields could potentially increase grain yield and biomass feedstock production was tested in this study using a statewide analysis of predominantly corn- and soy-producing counties in Iowa. Basic and rigorous controls on permissible soil and soil-carbon losses were imposed on harvest of crop residues to enhance year-to-year sustainability of crop and residue production. Additional criteria limiting harvesting costs and focus on large-area subfields for biomass production were imposed to reduce the impacts of energy crop integration on grain production. Model simulations were conducted using 4 years (2013-2016) of soil, weather, crop yield, and management practice data on all counties in Iowa. Miscanthus (Miscanthus x giganteus), switchgrass (Panicum virgatum), and crop-residue-based bioenergy feedstock systems were evaluated as biomass. Average energy crop and plant residue harvesting efficiencies were estimated at 50 and 60%, respectively. Because of higher potential yields, average logistics costs for miscanthus-based biomass production were 15 and 23% lower than switchgrass-based and crop residue-based biomass productions, respectively, under basic sustainability controls, and 17 and 26% lower under rigorous sustainability controls. Subfield shape, size, area, and harvest equipment size were the dominant factors influencing harvesting cost and efficiency suggesting that in areas where subfields are predominantly profitable or harvesting efficiencies low, other options such as prairie strips, buffer zones around fields, and riparian areas should be investigated for more profitable biomass production and sustainable farming systems. [ABSTRACT FROM AUTHOR]

Integrated landscape management has emerged in recent years as a methodology to integrate the environmental impacts of various agricultural practices along with yield and profitability in a variety of cropping systems. In this study, the Landscape Environmental Assessment Framework (LEAF), a decision support toolset for use in integrated landscape management and developed at Idaho National Laboratory, was used to evaluate the profitability of grain-producing subfields, to determine the efficacy of sustainably harvesting residual biomass after grain harvest, and to determine the efficacy of integrating bioenergy crops into grain-producing landscapes to enhance farmer profitability. Three bioenergy crops, sorghum, switchgrass, and miscanthus, were integrated into non-profitable subfields in four US counties. The manuscript describes in detail the material and methods used to define crop rotations, land management units and practices, subfield units and productivity, grain profitability, sustainability criteria, energy crop integration, and feedstock cost estimation. With the integration of bioenergy crops, the overall annual biomass production rates in the four counties could be increased by factors ranging from 0.8 to 21, depending on the energy crop and county, over the annual residue biomass production rates. By modeling the harvesting of residual biomass and energy crops using geo-referenced, precision harvesting equipment and optimal harvesting paths on individual subfields, the average logistics costs including harvesting of both residual biomass and energy crops were observed to fall well below US DOE's 2017 goals for biomass feedstock price of US$84/ton or US$92.6/dry Mg. Miscanthus, grown in counties in Ohio and Kansas, provided the maximum potential, among the three energy crops considered, for increment in biomass production and also posed maximum threat to the grain production. Considerable variability was observed in the harvesting and total costs because of the size, shape, and productivity of individual subfields. It was shown that variability in the harvesting costs could be used to down-select non-profitable farms with low harvesting costs and high residue and bioenergy crop yields and to reduce the negative impacts of bioenergy crop integration into croplands on grain production. The results of the assessment suggest that (1) the potential to produce biomass is considerably enhanced when non-profitable grain-producing subfields are replaced by bioenergy crops and (2) the subfield-scale integrated landscape assessment provides a defensible methodology to directly address individual farmer's profitability, sustainability, and environmental stewardship. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass in bale form has a low bulk density. Current in-field balers can achieve a bulk density of merely 120 to 180 kg dry matter (DM) m, whereas modern high-compression cutting balers produce up to 230 kg m. Mechanical compression is a straightforward technique to increase the material density, which significantly improves the efficiency of transportation and storage, and simplifies handling. Traditional compression technology mainly produces pellets, but conceivably bales could be compressed to a higher density as well. To design compression machinery in general, it is essential to determine the mechanical properties of biomass under compression and compression energy consumption. In addition, the material rebound percentage after compression is needed to design low-cost containerization methods for highly compressed bales. In this research, we established pressure-bulk density relationships and calculated Poisson's ratio for Miscanthus ( Miscanthus × giganteus, Poaceae/Gramineae) and switchgrass ( Panicum virgatum L. Poacea/Gramineae). We also calculated rebound percentages for Miscanthus in two particle sizes. The results showed that the energy consumption for compression of Miscanthus and switchgrass is low, ranging from 0.01 to 0.05 % of the inherent heating value of the materials. Poisson's ratios of Miscanthus and switchgrass ranged from 0.2 to 0.3 for various particle sizes. The rebound percentage was found as 28 % for unground Miscanthus and 23 % for Miscanthus ground to 6.35-mm particles. A common opinion is that high-level compression of biomass may reduce its energy content. Although in this research some of the biomass was exposed to an extreme pressure of 750 MPa, microscopic imagery revealed no fractions in the cell walls, leading to the conjecture that compression does not negatively impact the conversion potential of the biomass. [ABSTRACT FROM AUTHOR]

The potential use of lignocellulosic biomass as the feedstock for fumaric acid production and to select the specific Rhizopus oryzae strain for bioproduction was investigated in the current work. For this purpose, alkaline pretreatment of the biomass from perennial grasses, silver grass (Miscanthus sp.) and switchgrass (Panicum virgatum), and hemp (Cannabis sativa) was performed followed by enzymatic saccharification. The hydrolysate so obtained, was used as the feedstock for fumaric acid production. Silver grass was identified as the ideal perennial lignocellulosic biomass due to its higher reducing sugar concentration of 39.55 g/L as well as a yield of 0.79 g/g of pretreated biomass. The use of the hydrolysate for fumaric acid production, by three R. oryzae strains namely NRRL 1526, NRRL 6400 and NRRL 2582, yielded acid concentrations of 8 – 9 g/L. The strain NRRL 1526 was identified as the promising strain for fumaric acid bioproduction, as it provided the highest fumaric acid productivity of 0.19 gL−1h−1. [Display omitted] • High biomass yielding grasses and hemp used as feedstock • Miscanthus sp. (silvergrass) identified as the promising feedstock • Silvergrass yielded 0.38 g/g of sugar to achieve concentration of 39 g/L • 8–9 g/L fumaric acid obtained with yields of 0.3–0.5 g/g • Three Rhizopus oryzae strains investigated for fumaric productivity [ABSTRACT FROM AUTHOR]

This study integrates a biophysical model with a county-specific economic analysis of breakeven prices of bioenergy crop production to assess the biophysical and economic potential of biofuel production in the Midwestern United States. The bioenergy crops considered in this study include a genotype of Miscanthus, Miscanthus× giganteus, and the Cave-in-Rock breed of switchgrass ( Panicum virgatum). The estimated average peak biomass yield for miscanthus in the Midwestern states ranges between 7 and 48 metric tons dry matter per hectare per year ( t DM ha−1 yr−1), while that for switchgrass is between 10 and 16 t DM ha−1 yr−1. With the exception of Minnesota and Wisconsin, where miscanthus yields are likely to be low due to cold soil temperatures, the yield of miscanthus is on average more than two times higher than yield of switchgrass. We find that the breakeven price, which includes the cost of producing the crop and the opportunity cost of land, of producing miscanthus ranges from $53 t−1 DM in Missouri to $153 t−1 DM in Minnesota in the low-cost scenario. Corresponding costs for switchgrass are $88 t−1 DM in Missouri to $144 t−1 DM in Minnesota. In the high-cost scenario, the lowest cost for miscanthus is $85 t−1 DM and for switchgrass is $118 t−1 DM, both in Missouri. These two scenarios differ in their assumptions about ease of establishing the perennial crops, nutrient requirements and harvesting costs and losses. The differences in the breakeven prices across states and across crops are mainly driven by bioenergy and row crop yields per hectare. Our results suggest that while high yields per unit of land of bioenergy crops are critical for the competitiveness of bioenergy feedstocks, the yields of the row crops they seek to displace are also an important consideration. Even high yielding crops, such as miscanthus, are likely to be economically attractive only in some locations in the Midwest given the high yields of corn and soybean in the region. [ABSTRACT FROM AUTHOR]

Biofuels from crops are emerging as a Jekyll & Hyde – promoted by some as a means to offset fossil fuel emissions, denigrated by others as lacking sustainability and taking land from food crops. It is frequently asserted that plants convert only 0.1% of solar energy into biomass, therefore requiring unacceptable amounts of land for production of fuel feedstocks. The C4 perennial grass Miscanthus× giganteus has proved a promising biomass crop in Europe, while switchgrass ( Panicum virgatum) has been tested at several locations in N. America. Here, replicated side-by-side trials of these two crops were established for the first time along a latitudinal gradient in Illinois. Over 3 years of trials, Miscanthus× giganteus achieved average annual conversion efficiencies into harvestable biomass of 1.0% (30 t ha−1) and a maximum of 2.0% (61 t ha−1), with minimal agricultural inputs. The regionally adapted switchgrass variety Cave-in-Rock achieved somewhat lower yields, averaging 10 t ha−1. Given that there has been little attempt to improve the agronomy and genetics of these grasses compared with the major grain crops, these efficiencies are the minimum of what may be achieved. At this 1.0% efficiency, 12 million hectares, or 9.3% of current US cropland, would be sufficient to provide 133 × 109 L of ethanol, enough to offset one-fifth of the current US gasoline use. In contrast, maize grain from the same area of land would only provide 49 × 109 L, while requiring much higher nitrogen and fossil energy inputs in its cultivation. [ABSTRACT FROM AUTHOR]