Willow Biomass Production Research Articles

Effects of soil moisture and an AC-electric field on the phytoremediation of the Cd-contaminated soil

ABSTRACT Phytoremediation enhanced by electric field has been considered a green and low-cost technology for remediating heavy metal-contaminated soils. Soil moisture is a main environmental factor that affects Cd availability in the soil. However, the effects of soil moisture and AC-electric field on the remediation efficiency of willow (Salix spp.) and S. Alfredii interplanted together remain unclear. In the present study, we designed four treatments (60% soil field capacity, 60% soil field capacity + 0.5 V·cm−1 AC, 100% soil field capacity, 100% soil field capacity + 0.5 V·cm−1 AC) to explore the impacts of soil moisture and AC-electric field on soil Cd availability and Cd accumulation in plants. The results showed that the application of an AC-electric field significantly increased soil Cd availability by 20.9% and 10.8% under both 60% and 100% soil field capacity, respectively. Both high water with and without AC-electric field treatments reduced the proportion of acid-extractable and reducible Cd of soil but increased the proportion of residual Cd. Compared with the control, an AC-electric field with 60% soil field capacity significantly enhanced the biomass of S. Alfredii shoots by 31.2% and increased Cd accumulation in willow leaves and S. Alfredii shoots by 14.6% and 32.3%, respectively. In addition, the biomass production of willow was significantly enhanced but the uptake of Cd by willow was dramatically decreased under an AC-electric field with high water treatment. Therefore, these results suggest that the AC-electric field combined with 60% soil field capacity may be a more promising remediation technique to clean up the Cd-contaminated soil.

Validation of the Taguchi method on the example of evaluation of willow biomass production factors under environmental stress

Climate change requires the introduction of crop production technologies that guarantee stable yields under exposure to extreme weather events. The main focus should be on the reliability of yields, even if it implies a reduction in agricultural outputs. In the theory and practice of industrial experiments, Taguchi methods have been deployed to identify production technologies that are most resilient to the random effects of uncontrollable disrupting production factors. This is the first ever study where the Taguchi method was deployed in an agricultural field experiment to identify the levels of two fundamental production factors (genotype and planting density) that were most effective in stabilizing willow (Salix spp. L) biomass yields under variable uncontrollable abiotic and biotic stresses in annual harvest rotation. The analysis was based on the results noted in the first 12 consecutive years of a long-term field experiment in northern Poland. The results of the analysis involving the Taguchi method were validated under field conditions, and they were logical and consistent with the results of statistical analyses that are widely applied in this type of research. Uncontrollable stressors significantly influenced the levels of the least resilient production factors that were identified by the Taguchi method. The research assumptions were validated, which suggests that the Taguchi method could be considered in field experiments.

Impact of stem age and winter outdoor storage on willow chip chemical composition and physicochemical properties

Willow (Salix) biomass production has been expanding dramatically in recent years with the development of phytoremediation and wastewater treatment projects and plans to build bio-refineries are increasing the future options for valorizing this biomass. In this context, winter storage of biomass after harvesting is unavoidable, due to limited shelter capacity. Questions about the impact of outdoor storage during winter and stem age at harvest time led to the establishment of an experiment on the site of Ramo®, a biomass-based products producer. Two- and three-year-old Salix miyabeana ‘SX67′ stems were chipped and piled after leaf fall in November 2018. Temperature was measured during the experiment, while physicochemical parameters and biomass composition were analyzed at the beginning and the end. The experiment showed that stem age influenced the initial biomass composition, with the two-year-old stems containing more extractives and the three-year-old stems containing more structural sugars. Heat production varied with stem age, which was reflected in the final biomass composition. A loss of extractives and an increase in lignin was measured in both stem types, while an increase in glucan, xylan and mannan was also measured in the two-year-old chips. This new information complements existing data on mass loss during wood chip storage and provides essential knowledge for future decision-making related to the development of lignocellulose value chains from bioenergy crops.

Beyond Tsunami disaster: Ten years’ activities to use uncultured field for biomass production of willow after the Great East Japan Earthquake in Miyagi, Japan

Beyond Tsunami disaster: Ten years’ activities to use uncultured field for biomass production of willow after the Great East Japan Earthquake in Miyagi, Japan

A semi‐commercial case study of willow biomass production in the northeastern United States

AbstractShrub willow (Salix spp. and hybrids) is a biomass crop well adapted to the northeastern United States. We assessed the biomass productivity of six willow cultivars in a 14.5‐ha field in Pennsylvania through two rotation cycles of 3 yr each, comparing the realized and biophysical yield potential. We also evaluated the relationship of yield with plant density and the harvest efficiency. The realized yield of the best cultivars was about 8 Mg ha–1 yr–1, well below the calculated harvestable potential of 14 Mg ha–1 yr–1. Uniform stands of willow without planting gaps may maximize yield with 8 × 103 plants ha–1, but upright cultivars may benefit from higher densities. Harvest is relatively slow at 1 ha h–1 or 20 Mg h–1 in the longest rows with optimal ground conditions, which makes the harvest cost per hour high. Biotic stresses built up gradually during the 7 yr of the experiment affecting two cultivars severely. The cultivar S. miyabeana × S. viminalis ‘Preble’ was defoliated by a growing population of willow leaf beetle (Plagiodera versicolora), whereas the cultivar S. purpurea ‘Fish Creek’ was affected by two fungal diseases and suffered a major stand loss in the winter of 2019/2020. Both examples justify breeding for insects and diseases resistance. The moderate harvestable yield and high harvest cost imply that in the northeastern United States, the viability of willow for bioenergy with carbon capture and storage as a tool to reduce CO2 emissions may depend on the provision and monetization of additional ecosystem services.

Willow Biomass Crops Are a Carbon Negative or Low-Carbon Feedstock Depending on Prior Land Use and Transportation Distances to End Users

Few life cycle assessments (LCAs) on willow biomass production have investigated the effects of key geographically specific parameters. This study uses a spatial LCA model for willow biomass production to determine spatially explicit greenhouse gas (GHG) emissions and energy return on investment (EROI), including land use conversion from pasture and cropland or grassland. There were negative GHG emissions on 92% of the land identified as suitable for willow biomass production, indicating this system’s potential for climate change mitigation. For willow planted on cropland or pasture, life cycle GHG emissions ranged from −53.2 to −176.9 kg CO2eq Mg-1. When willow was grown on grassland the projected decrease in soil organic carbon resulted in a slightly positive GHG balance. Changes in soil organic carbon (SOC) associated with land use change, transportation distance, and willow yield had the greatest impacts on GHG emissions. Results from the uncertainty analysis exhibited large variations in GHG emissions between counties arising from differences in these parameters. The average EROI across the entire region was 19.2. Willow biomass can be a carbon negative or low-carbon energy source with a high EROI in regions with similar infrastructure, transportation distances, and growing conditions such as soil characteristics, land cover types, and climate.

Neutralizing global warming impacts of crop production using biochar from side flows and buffer zones: A case study of oat production in the boreal climate zone

Rapid climate change mitigation requires carbon sequestration in addition to greenhouse gas emission reductions. Agriculture may have a high potential for carbon sequestration due to improved practices. However, it is not known how the global warming impacts of crop production could be mitigated especially within an agricultural system. The aim of this study is to evaluate possibilities to neutralize global warming impacts in crop production using biochar produced from side flows and buffer zone biomass. A life cycle assessment methodology is utilized in this research for oat production in the boreal climate zone. Global warming impact reductions are compared for three different side flow utilization options. Traditionally, side flows have been utilized in energy or fodder production, and these options are compared to biochar production at a system level. The potential to use buffer zone biomass for biochar production is also studied. Willow has been selected as a biomass source in buffer zones. Oat production leads to greenhouse gas emissions especially due to the use of fossil and mineral fertilizers in cultivation and heat energy, electricity and fuels in various process phases. The production of one metric ton of oat flakes from cradle to gate generates 700 kg of CO2eq emissions. Biochar and energy production from side flows enables a greater reduction in global warming impacts than the feed use of side flows. Buffer zones in willow biomass and biochar production may enable the full neutralization of the global warming potential of oat production within an agricultural system. Further research with actual measurements is required especially on biochar impacts on soil emissions such as N2O. This research shows that it could be possible to neutralize global warming impacts from crop production using available technologies and available biomass in agricultural systems. A framework is created for carbon neutral crop production using side flows and buffer zone biomass through biochar.

A stochastic techno‐economic analysis of shrub willow production using EcoWillow 3.0S

AbstractEcoWillow 3.0S is a techno‐economic analysis (TEA) tool that calculates realistic willow biomass production costs using data from field trials of willow production in New York State. The model represents the input parameters for diesel fuel price, wood price, and willow yield as data‐derived probability distributions rather than as single values. This study uses EcoWillow 3.0S with Oracle Crystal Ball to perform a stochastic TEA of shrub willow production in the northeastern USA. Two outputs obtained from this model are a 24‐year net present value (NPV) and minimum selling price (MSP) of shrub willow production under price and yield uncertainty. The MSP for dry willow ranges within a 95% confidence interval from $59–$102/Mg. The NPV, also within a 95% confidence interval, ranges from −$153 819 to $207 129 for 40 ha of willow harvested seven times over 24 years. The relevance of this study is to use the TEA methodology to assess the financial feasibility of shrub willow production as a bioenergy feedstock. The results of this analysis provide the bioenergy field with NPV and MSP probability distributions on shrub willow production that have previously been absent from the refereed literature. Using data collected from field operations over a number of years, EcoWillow 3.0S captures some of the key inputs that influence the variation in the delivered cost of willow biomass crops. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

Fire-mediated patterns of habitat use by male moose (Alcesalces) in Alaska

Fire severity is an important control over regeneration of deciduous species and can influence the overall quality of habitat for herbivores, such as moose (Alces alces (Linnaeus, 1758)), but the relationships between availability and duration of biomass production and moose habitat use are largely unknown. We evaluate the relative influence of a regenerating burn, paying particular attention to fire severity, on winter forage production and duration, offtake, nutritional quality, and seasonal moose habitat use. We used data from 14 GPS collared male moose in the 20-year-old Hajdukovich Creek Burn (HCB) in interior Alaska, USA, to generate seasonal dynamic Brownian bridge movement models. Within HCB, moose selected for low-severity sites more than high- and moderate-severity sites during the winter. Over the past decade, willow (species of the genus Salix L.) biomass production in low-severity sites has doubled and is likely influencing winter habitat selection patterns. In summer, moose selected for high-severity sites where there is a more abundant understory layer (e.g., stem densities) providing both forage and cover. The initial pulse of biomass production in high-severity sites, as well as the delay in growth and maturation of vegetation in low-severity sites, indicate that differing distributions of wildfire severity can create a dynamic mosaic of habitat patches that may extend the value of burns over time for moose.

Shrub Willow Biomass Production Ranking Across Three Harvests in New York and Minnesota

Shrub willow has potential for being a viable dedicated bioenergy crop in temperate northern latitudes of the USA. Selection of high-producing willow cultivars is critical for economic viability and long-term sustainability of willow production systems. Long-term trials are needed in different geographic areas to better understand genetic by environment interactions on biomass yield for greater profitability and to enhance future breeding efforts. Field trials were conducted in two contrasting environments, northern New York and southern Minnesota, to explore changes in shrub willow yield ranking over three harvest cycles across a range of cultivars and diversity groups. Overall, the MN site produced higher, more stable biomass yields than the NY site due primarily to more productive soils, warmer climate, and less weed pressure. However, between-site differences in willow biomass yield were nominal after the second harvest cycle. Yield variability among the top five willow cultivars at each harvest was significantly less than variability among all cultivars regardless of site. Shrub willow cultivars identified in the top-ranking groups were different between sites. Results show that willow can be a viable long-term crop for sustained biomass feedstock production across a wide range of soils and climates but proper cultivar selection is critical for biological and economic success.

Willow biomass and cuttings' production potential over ten successive annual harvests

Willow nursery plantations for cuttings' production, which provide planting material for new, improved varieties, can be set up in greater densities and must be harvested in one-year cycles. Therefore, the aim of this study was to determine the effect of planting density on the survival rate, yield and production potential of cuttings of two varieties and three clones in ten successive one-year harvest cycles. The experiment was conducted in the years 2004–2013 in northern Poland. Significant differentiation regarding the biomass yield and the number of cuttings was demonstrated not only between the planting densities, but also between the varieties/clones and the interactions between those factors. The final survival rate was close to 85% with a planting density of 12 000 ha−1and 24 000 ha−1. However, the survival rate was half that at the highest planting density. The varieties and clones differed in their morphological features, which affected their yield, both as chips and cuttings number. The best results were achieved for the UWM 095 clone and the Tur variety. The yield varied over the next ten years, but it was not found to decrease as the plantation aged. An increase in planting density from 12 000 ha−1 to 24 000 ha−1 resulted in greater yield, but a further increase to 48 000 ha−1and 96 000 ha−1 did not bring such effects. The production of cuttings could bring more than 20 times higher potential income compared to the production of chips for energy purposes.

Effects of Cutting Phenology (Non-dormant Versus Dormant) on Early Growth Performance of Three Willow Clones Grown Under Different Weed Treatments and Planting Dates

To assess the effects of cutting phenology on early growth performance of three willow clones grown under different weed treatments and planting dates, freshly harvested (non-dormant) and cold-stored (dormant) cuttings from willow clone Tora, Jorr, and Olof were planted in bucket experiment outdoors in central Sweden on five planting dates (May–June 2013) with or without a model weed (spring barley). Non-dormant cuttings sprouted faster than dormant cuttings when planted early in the season. For cuttings planted later in the season, bud sprouting was affected only by willow clone. Aboveground biomass production was affected by cutting phenology, planting date, clone, and weed treatment. When planted on May 3 and May 10, biomass produced from non-dormant and dormant cuttings did not differ, while willows grown from dormant cuttings produced 59% more aboveground biomass than willows grown from non-dormant cuttings when planted on May 24–June 16. Tora produced on average 12% more biomass than Jorr and Olof, and weed competition reduced aboveground biomass production on average with 36%. The ability of willow to suppress weeds (WSA) was 26 (non-dormant cuttings) and 12% (dormant cuttings) higher for willows planted on May 3 compared with WSA of willows grown from cuttings planted later in the season. The ability to tolerate competition from weeds (WT) was 51 and 52% lower for willows grown from non-dormant and dormant cuttings planted late in the season compared with WT of willows planted earlier in the season. We conclude that planting with long-term cold storage of willow cuttings can be replaced with planting freshly harvested cuttings when planting is performed in early season, and that weed competition strongly reduces biomass production. Weed control during the establishment phase is crucial in order to maximize willow biomass production.

Establishment and Early Growth of Willow at Different Levels of Weed Competition and Nitrogen Fertilization

To evaluate the effects of weed competition and nitrogen fertilization on the early growth performance of willow, cuttings of the clone Tora (Salix schwerinii x S. viminalis) were planted in buckets together with model weeds (spring barley or white mustard) sown 15, 26, and 30 days after willow planting. The buckets were fertilized with 30 or 90 kg N ha−1. Willow with weeds sown after 15 days produced less biomass and smaller leaf area and had a lower maximum shoot height compared to willow planted without weeds and willow with weeds sown after 26 or 30 days. Fertilization with 90 kg N ha−1 gave higher willow biomass production in willow with weeds sown after 26 or 30 days. Type of model weed had no effect on willow performance. Weed biomass and maximum shoot height were higher in weeds planted without willows compared to the willow-weed mixtures. A high nitrogen level gave more weed biomass when planted without willows and in the willow-weed mixture with weeds sown after 15 days. We conclude that for the given high density of willow, competition from weeds emerging soon after willow planting had strong effect on early production. Furthermore, if there is a risk of weed infestation, fertilization should be delayed.

Fast-Growing Energy Crops Grown In Conditions Of Slovakia In The Context Of The EU Energy Policy

Abstract The energy-efficient low-carbon EU economy (known as the 20-20-20) sets fundamental objectives in reducing greenhouse gas emissions (20%), increasing the share of renewable energy sources (20%) and saving primary energy consumption (20%). The objectives are incorporated in the National Renewable Energy Action Plans (NREAPs). Slovakia has to increase the share of renewable energy sources (RES) by 14% in its energy mix by 2020. Currently, the most widely used RES are water and solar energy, biomass and biogas. Our country has suitable ecological conditions for growing the so called energy crops in lowland and upland areas. So far, however, there is a lack of science-based information on the potential production of biomass in different soil-ecological and climatic conditions of the Slovak Republic. Our experimental research is focused on quantification of biomass production of various willow (genus Salix), poplar (genus Populus) and silvergrass (Miscanthus sinensis) varieties grown in ecological conditions of southern Slovakia. We evaluated the biomass production of the studied crops. The results were evaluated in terms of the EU call (2013): to obtain more energy while reducing inputs and negative environmental impacts.

The Energy Efficiency Of Willow Biomass Production In Poland – A Comparative Study

Abstract Field experiments with willow (Salix L.) coppice cultivation and Eko-Salix systems have been conducted at the University of Warmia and Mazury since 1992. In that wider context, the aim of the work described here was to compare energy inputs involved in setting up a plantation and producing biomass, and to assess the efficiency of willow-chips production under the coppice and Eko-Salix systems. The energy gain determined in the experiments was several to more than twenty times as great as the inputs needed to operate the plantation and to harvest willow biomass, this leaving both systems of willow cultivation under study attractive where setting up short-rotation coppices is concerned.

Biomass production and soil nutrients in organic and inorganic fertilized willow biomass production systems

The use of organic waste materials as nutrient sources for willow biomass production is an attractive means to decrease fertilization costs, increase biomass production and reduce greenhouse gas emissions associated with the system. In this study, changes in soil nutrients and biomass production of two willow varieties (Salix miyabeana–SX64 and Salix purpurea–9882-34) in organic and synthetic fertilized systems were compared at three locations in Northeastern U.S.A: Middlebury VT (MID), Delhi NY (DEL) and Fredonia NY (FRE). A 150 and 200 kg available N ha−1 of urea as commercial fertilizer (CF), biosolid compost (BC) and digested dairy manure (DM) and a control (CT0) treatments were applied in June 2008 to the willow which was re-sprouting after coppice. There was no significant difference (p > 0.05) in biomass production among the fertilization treatments at any of the three sites and for either of the varieties. First rotation biomass production of 9882-34 ranged from 9.0 to 11.6 Mg ha−1 yr−1 at DEL, 3.4–8.8 Mg ha−1 yr−1 at MID and 3.5–7.7 Mg ha−1 yr−1 at FRE. For SX64, biomass production ranged from 13.2 to 19.0 Mg ha−1 yr−1 at DEL, 9.0–15.0 Mg ha−1 yr−1 at Mid and 5.5–9.3 Mg ha−1 yr−1 at FRE. SX64 deployed small numbers of large stems and produced more biomass than 9882-34 which deployed large numbers of small stems. Application of BC significantly increased soil N and P levels at MID in both 2008 and 2009 (p < 0.05). At DEL, BC and DM treatments increased soil N, Ca, Mg and OM levels in both 2008 and 2009 (p < 0.05). The fertilization treatments had no significant effect on any soil nutrients at FRE. This study indicates that willow biomass can be produced without fertilizer additions in the first rotation across this range of sites due to the nutrient status of these sites and high internal nutrient cycling in these systems.

Life cycle assessment of two alternative bioenergy systems involving Salix spp. biomass: Bioethanol production and power generation

Two energy production systems using short rotation coppice (SRC) willow chips were evaluated: bioethanol production via enzyme-catalyzed hydrolysis and electricity production following a biomass integrated gasification combined cycle scheme.The most relevant input and output flows of each renewable energy system were identified and quantified throughout the life cycle from the SRC willow plantation to the bioenergy plant gate. Both bioenergy systems were found to be feasible from an energy perspective. Moreover, they entailed environmental benefits when compared to conventional energy practices. However, improvements relating to not only willow biomass production but also bioenergy conversion-related activities should be considered. In this respect, the process steps that provided the highest environmental impacts have been highlighted.Furthermore, well-to-wheels environmental characterization results were estimated and compared for the bioethanol and bioelectricity scenarios. In this sense, the identification of the most appropriate processing route for willow chips was found to be highly dependent on the impact category under assessment. In particular, global warming and energy parameters led to opposite conclusions. While the bioethanol scenario arose as the potentially best choice from an energy perspective, the bioelectricity scenario seems to be a more suitable alternative when global warming is the decisive factor.

Willow biomass production under conditions of low-input agriculture on marginal soils

In this study, the biomass yield and morphological traits of plants were reported from an experiment involving six genotypes of willow in northern Poland. Willow was planted using a pole cutting system, which we designated Eco-Salix, on sites that were unsuitable for food crops. The results presented here are from the first rotation of a four-year cutting cycle. In the field trial, the average willow biomass yield of oven-dry matter was 7.87 Mg ha −1 year −1. Willow plants that were planted as pole cuttings after four growing seasons reached a height of 6.64 m and a stem diameter of 50.5 mm. Clone UWM 043 produced higher yields and more favourable morphological traits when compared to registered Polish cultivars. The willow biomass yield obtained on peaty muck soil was significantly higher than from willow that was grown on heavy textured silt soil. The biomass harvested from plots planted at a density of 5,200 plants ha −1 was 14% lower than plots that had a density of 7,400 plants ha −1.

Lighting the way to willow biomass production

Biofuels produced from willow could help reduce our dependence on fossil fuels. To maximise yields per hectare light interception and utilisation of the plant canopy need to be optimised. Jennifer Cunniff and Marianna Cerasuolo explain how this target can be reached by integrating morphological field measurements and modelling techniques.

Dolomite limestone application as a chemical immobilization of metal-contaminated soil

In this experiment we proved an effect of dolomite limestone on chemical immobilization in soil contaminated by trace metals, namely Cd, Pb, and Zn. Primary, we set up lysimeter pot experiment to measure soil leaching without vegetation. Willow clone (S. &amp;times; smithiana Willd) was cultivated in the second lysimeter pot as a new approach to monitor Pb, Cd and Zn leaching, which was affected by soil liming (used in 1% rate). At the time of both harvests, aboveground biomass increased significantly at the amended variant. After the second harvest aboveground biomass production increased by 80% in comparison with the first one, Cd and Zn concentration in biomass decreased 2-fold and 3-fold, respectively. Dolomite limestone as a process of liming: (i) restricted metals leaching from the soil substrate; (ii) reduced metal uptake by willow; and (iii) increased biomass production of willow. Liming also alleviated the plant stress imposed by risk elements resulting in better plant growth and lower levels of stress markers (total nitrogen content and the main amino acid metabolism parameters in the willow leaves) yet through different mechanisms.