Search Results (170)

Agroforestry is defined as a multifunctional approach to land management that enhances biodiversity and soil health while mitigating environmental impacts compared to intensive agriculture. The efficacy of maize cultivation in agroforestry systems is significantly influenced by nutrient competition. The factors that influence this phenomenon include the dimensions and configuration of the tree rows, as well as the availability of nutrients. This study examined the effect of nitrogen fertilization, tree line spacing, and seasonal changes on the productivity and the leaf spectral characteristics of the intercropped maize (Zea mays L.) within a willow-based agroforestry system in eastern Hungary. The experiment involved the cultivation of maize with two spacings (narrow and wide field strips) and four nitrogen levels (0, 50, 100, and 150 kg N ha⁻¹) across two growing seasons (2023–2024). The results demonstrated that yield-related parameters, including biomass, cob size and weight, and grain weight, exhibited a strong response to nitrogen level and tree line spacing. The reduction in spacing resulted in a decline in maize productivity. However, a high nitrogen input (150 kg N ha⁻¹) partially mitigated this effect in the first growing season. Vegetation indices demonstrated a high degree of sensitivity to annual variations, particularly with regard to tree competition and weather conditions. Multispectral vegetation indices exhibited a heightened responsiveness to environmental and management factors when compared to indices based on visible light (RGB). The findings of this study demonstrate that a combination of optimized tree spacing and optimized nitrogen management fosters productivity while maintaining agroecological sustainability in temperate agroforestry systems. Full article

Soil lead (Pb) contamination poses a severe threat to agricultural sustainability and food security. Phytoremediation offers a green alternative for remediation, yet its efficiency is limited by poor plant tolerance and restricted metal uptake. In this study we investigated the functional roles of the microbial inoculants Trichoderma guizhouense NJAU4742 and Bacillus velezensis SQR9 in enhancing the performance of Salix suchowensis P1024 grown in Pb-contaminated soil. NJAU4742 significantly increased plant biomass by 34% (p < 0.05), accompanied by increased soil microbial biomass and higher activities of urease, acid phosphatase, and sucrase. In contrast, SQR9 strongly enhanced Pb accumulation by 19% (p < 0.05), which was accompanied by upregulated antioxidant enzymes, reduced lipid peroxidation, and elevated cysteine levels. Random forest and correlation analyses demonstrated that soil nutrient cycling indices (urease, MBC, sucrase) were key predictors of biomass, whereas antioxidant defenses (POD, CAT) primarily explained Pb accumulation. These findings provide new insights into the distinct contributions of NJAU4742 and SQR9 to willow growth and Pb remediation, and provide a basis for developing more effective microbe-assisted phytoremediation strategies. Full article

Pelletizing enhances competitiveness of lignocellulosic biomass (LCB) as a fuel by increasing its bulk and energy density. However, LCB pellets are prone to degradation from moisture, have high ash, and pose safety risks due to carbon monoxide (CO) emissions during storage. Hot water extraction (HWE), a mild hydrothermal treatment particularly effective for angiosperms, removes most hemicelluloses (xylans), reduces ash, and increases lignin content in remaining HWE-LCB. Based on the current understanding of CO formation, these changes suggested that HWE could reduce CO emissions. In this study, we evaluated the effects of HWE on pellets made from shrub willow, miscanthus, and wheat straw. A statistical analysis was conducted on ash, energy content, bulk density, durability, pellet length and density, moisture absorption, and CO emissions. All HWE-LCB pellets demonstrated significant increases in energy content (up to 3.54%) and reductions in moisture absorption (up to 23.84%). Although not all effects reached statistical significance, HWE generally had positive effects on ash content, bulk density, durability, and average pellet length and density. Contrary to expectations, HWE-LCB pellets emitted significantly more CO under both ambient and isothermal temperature conditions (up to 4.25 times overall increase), although still less than commercial hardwood/softwood blend pellets (<200 ppm in HWE-LCB vs. >300 ppm). Full article

This study describes the development and characterization of materials based on activated carbon (AC). Pellets composed of dried biomass of willow, knotweed, and maple were formed and pyrolyzed to obtain different types of AC. Nickel (Ni) nanoparticles were synthesized on these materials using a bottom-up strategy by impregnating the carbons with a nickel nitrate solution. To characterize the surface and structure of these materials, SEM, MP-AES, and DSC-TGA techniques were employed. The ash content was analyzed to determine the input of mineral components in the carbons. The DSC-TGA results showed good thermal stability for each of the carbons, even at a temperature of 800 °C. BET analysis was also conducted, and the isotherms revealed well-developed surfaces for most of the specimens. The high efficiency of the impregnation process was confirmed by the MP-AES results: 165 mg of Ni was deposited on 1 g of carbon derived from maple leaves. The adsorbed Ni was well distributed across the carbon surfaces, as demonstrated in micrographs taken with the SEM-EDS apparatus. A comparison with similar materials reported in other studies was also performed. Full article

Shrub willow (Salix spp.) is a promising candidate for evapotranspiration (ET) covers due to its rapid growth and high water use. This study assessed 30 willow clones over two three-year rotations on a former industrial waste site in Solvay, NY, with alkaline, low-organic substrates and intermittent hardpan. Survival was high after the first rotation (87.9% ± 1.7 SE), but yield was lower and more variable (6.55 Mg ha⁻¹ y⁻¹ ± 0.25 SE) than on mineral soils. In the second rotation, both survival (42.6% ± 3.0 SE) and yield (5.08 Mg ha⁻¹ y⁻¹ ± 0.38 SE) declined. Clone rankings shifted between rotations (Spearman ρ = 0.13, p = 0.48), suggesting that short-term trials poorly predict long-term performance on degraded sites. Survival emerged as the primary driver of yield, with a smaller interaction from hardpan. Clone 05X-295-014 showed notable resilience, maintaining strong performance despite widespread hardpan. Five clones from S. miyabeana and S. purpurea x S. miyabeana groups demonstrated sustained or increasing yield and survival above 60%. These findings emphasize the importance of selecting for survival alongside yield in multi-rotation trials to ensure effective long-term deployment for biomass and phytoremediation in challenging sites. Full article

Willow stands (Salix spp.) are an essential part of riparian ecosystems, as they sustain biodiversity and provide bioenergy solutions. The present review synthesizes the global scientific literature about the management of willow stands. In order to achieve this goal, we used a dual approach combining bibliometric analysis with traditional literature review. As such, we consulted 416 publications published between 1978 and 2024. This allowed us to identify key species, ecosystem services, conservation strategies, and management issues. The results we have obtained show a diversity of approaches, with an increase in short-rotation coppice (SRC) systems and the multiple roles covered by willow stands (carbon sequestration, biomass production, riparian restoration, and habitat provision). The key trends we have identified show a shift toward topics such as climate resilience, ecological restoration, and precision forestry. This trend has become especially pronounced over the past decade (2014–2024), as reflected in the increasing use of these keywords in the literature. However, as willow systems expand in scale and function—from biomass production to ecological restoration—they also raise complex challenges, including invasive tendencies in non-native regions and uncertainties surrounding biodiversity impacts and soil carbon dynamics over the long term. The present review is a guide for forest policies and, more specifically, for future research, linking the need to integrate and use adaptive strategies in order to maintain the willow stands. Full article

International efforts are underway to implement carbon neutrality policies in rapidly changing climate conditions. This situation has strongly demanded the discovery of novel carbon sinks. The Salix genus has attracted attention as a promising carbon sink owing to its rapid growth and efficient use as a biofuel in short-rotation cultivation. The present study aims to derive an allometric equation and conduct stem analysis as fundamental tools for estimating net primary productivity (NPP) in Salix pierotii Miq. stand, which is increasingly acknowledged as an important emerging carbon sink. The allometric equations derived showed a high explanatory rate and fitness (R² ranged from 0.74 to 0.99). The allometric equations between DBH and stem volume and biomass derived in the process of stem analysis also showed a high explanatory rate and fitness (R² ranged from 0.87 to 0.94). The NPPs calculated based on the allometric equation derived and stem analysis were 11.87 tonC∙ha⁻¹∙yr⁻¹ and 15.70 tonC∙ha⁻¹∙yr⁻¹, respectively. These results show that the S. pierotii community, recognized as the representative riparian vegetation, could play an important role as a carbon sink. In this context, an assessment of the carbon absorption capacity of riparian vegetation such as willow communities could contribute significantly to achieving carbon neutrality goals. Full article

Land-based bioenergy systems are increasingly promoted for their potential to support climate change mitigation and energy security. Building on previous productivity and efficiency analyses, this study applies the MiscanFor and SalixFor models to evaluate land use energy intensity (LUEI) for Miscanthus (Miscanthus × giganteus) and willow (Salix spp.) under baseline (1961–1990) and future climate scenarios, and Business-as-Usual (B1) and Fossil Intensive (A1FI) scenarios, projected to 2060. The study also assesses the impact of biomass transport on energy use efficiency (EUE) and quantifies soil organic carbon (SOC) sequestration by Miscanthus. Under current conditions, Miscanthus exhibits a higher global mean LUEI (321 ± 179 GJ ha⁻¹) than willow (164 ± 115.6 GJ ha⁻¹) across all regions (p < 0.0001), with energy yield hotspots in tropical and subtropical regions such as South America, Sub-Saharan Africa, and Southeast Asia. Colder regions, such as Europe and Canada, show limited energy potential. By 2060, LUEI is projected to decline by 9–15% for Miscanthus and 8–13% for willow, with B1 improving energy returns in temperate zones and A1FI reducing them in the tropics. Global EUE for Miscanthus declines significantly (p < 0.0001) by 21%, from 15.73 ± 7.1 to 12.37 ± 5.2 as biomass transport distance increases from 50 km to 500 km. Mean SOC sequestration is estimated at 1.20 ± 1.46 t C ha⁻¹, with tropical hotspots reaching up to 4.57 t C ha⁻¹ and some cooler regions exhibiting net losses (–7.93 t C ha⁻¹). Climate change significantly reduces SOC gains compared to baseline (p < 0.0001), although differences between B1 and A1FI are not statistically significant. These findings highlight the importance of region-specific, climate-resilient biomass systems to optimize energy returns and carbon benefits under future climate conditions. Full article

Pellets can be produced not only from forest dendromass but also from agricultural dendromass derived from short rotation coppice (SRC) plantations, as well as surplus straw from cereal and oilseed crops. This study aimed to determine the thermophysical properties and elemental composition of 16 types of pellets produced from four types of forest biomass (Scots pine I, alder, beech, and Scots pine II), four types of agricultural biomass (SRC willow, SRC poplar, wheat straw, and rapeseed straw), and eight types of pellets from mixtures of wood biomass and straw. Another aim of the study was to demonstrate which pellet types met the parameters specified in three standards, categorizing pellets into thirteen different classes. As expected, pellets produced from pure Scots pine sawdust exhibited the best quality. The quality of the pellets obtained from mixtures of dendromass and straw deteriorated with an increase in the proportion of cereal straw or rapeseed straw in relation to pure Scots pine sawdust and SRC dendromass. The bulk density of the pellets ranged from 607.9 to 797.5 kg m⁻³, indicating that all 16 pellet types met the requirements of all six classes of the ISO standard. However, it was determined that four types of pellets (rapeseed, wheat, and two others from biomass mixtures) did not meet the necessary requirements of the Premium and Grade 1 classes. The ash content ranged from 0.44% DM in pellets from pure Scots pine sawdust to 5.00% DM in rapeseed straw pellets. Regarding ash content, only the pellets made from pure Scots pine sawdust met the stringent requirements of the highest classes, A1, Premium, and Grade 1. In contrast, all 16 types of pellets fulfilled the criteria for the lower classes, i.e., Utility and Grade 4. Concerning the nitrogen (N) content, seven types of pellets met the strict standards of classes A1 and Grade 1, while all the pellets satisfied the less rigorous requirements of classes B and Grade 4. Full article

This study evaluated the physiological responses and biomass production of selected poplar and willow clones cultivated in form of phytoremediation buffer plantations on landfills in Vinča (near Belgrade) and Novi Sad, Serbia. Key parameters assessed included net photosynthesis (A), transpiration (E), stomatal conductance (g_s), and water use efficiency (WUE). Results indicated a significant Clone × Site interaction for net photosynthesis, suggesting environmental-specific clone responses. Transpiration and stomatal conductance exhibited site-stable expression between sites, implying conservative traits or similar hydrological conditions during measurements. Particularly, total site values for physiological parameters were higher at the Novi Sad site, likely due to continuous access of plants to groundwater. The weak correlation between WUE and biomass production suggests that favorable water conditions at both sites diminished the importance of water use efficiency for biomass accumulation. Poplar clone S1-8 exhibited the highest biomass production and leaf-level gas exchange traits (A, E, g_s, WUE), reflecting a fast-growth strategy through increased gas exchange. This clone’s consistent productivity across sites classifies it as a generalist, while willow clone 378 and poplar clone 135/81, with significantly higher biomasses at the Novi Sad site than at the Vinča site, can be considered as specialists. Use of both generalist and specialist clones in multiclonal plantations may enhance phytoremediation and biomass production stability across variable sites. These findings underscore the importance of selecting appropriate clones for phytoremediation on landfills and on contaminated lands in general. Full article

Economic and legal conditions of the European power industry enforce higher participation of biomass in the thermal energy mix per power unit, due to the necessity of carbon dioxide emission reduction. One of the most important features dictating the suitability of biomass fuel for utilization in pulverized fuel-fired boilers is its grindability. The grindability of biomass is a difficult parameter to estimate due to its non-uniform morphology and inhomogeneous character. Milling and co-milling of large amounts of biomass can deteriorate the mill output and make it difficult to ensure the proper particle size distribution of the pulverized fuel fed into the combustion chamber. The main objective was to determine whether torrefaction pre-treatments could increase the grindability features of various types of biomass. Investigations of raw and torrefied biomass grindability were performed with the use of a modified Hardgrove Index for alder chips, palm kernel shells, and willow chips. Additionally, semi-industrial scale milling tests were performed, which allowed for the evaluation of torrefied biomass suitability for continuous grinding installations equipped with vertical spindle mills. According to the analysis, an increase in the biomass grindability index after the torrefaction process was shown. Additionally, it was noted that for milling low-density materials (e.g., torrefied biomass), changes in the construction of the industrial mill classifier may be necessary for the proper grinding circuit operation. Full article

Soil cadmium pollution poses significant environmental risks, prompting global concern. Previous studies have demonstrated that 24-epibrassinolide (Brs) can enhance plant photosynthesis, thereby potentially improving the efficiency of soil cadmium remediation by increasing biomass. Therefore, this study investigated the use of Brs to enhance Cd remediation by willow and alfalfa. After four months, we analyzed soil physicochemical properties, plant physiological and biochemical responses, biomass, Cd fractionation, plant Cd concentrations, and bioaccumulation factor (BCF). Willow and alfalfa cultivation without Brs increased soil pH and carbonates, reduced the exchangeable Cd fractionation, and increased Cd bound to Fe-Mn oxides and organic matter (p < 0.05). Conversely, Brs application increased soil total acids, increasing the bioavailable Cd (p < 0.05). Willow grown for four months accumulated Cd in leaves, stems, and roots at concentrations of 141.83−242.75, 45.91−89.66, and 26.73−45.68 mg kg⁻¹, respectively, with leaf BCF ranging from 14.53 to 24.88. After five months, leaves of willow planted in Cd-contaminated soil (9.65 mg kg⁻¹) contained 187.90−511.23 mg kg⁻¹ Cd, with BCFs of 19.25−52.38. Brs also increases plant biomass by improving photosynthesis, detoxification, and antioxidant defenses. Treatments with Brs and willow extracted 1.57−1.81 times more Cd (0.56−1.37 mg pot⁻¹) than without Brs (0.31−0.87 mg pot⁻¹). This study offers guidelines for Cd phytoremediation and highlights an effective strategy to enhance Cd accumulation. Full article

In recent decades, there has been a significant decrease in humus resources in the terrestrial environment, including in agriculturally used soils, due to increased mineralisation of soil organic matter (SOM). Using composting as a method for recycling lignin-cellulosic biomass, the application of innovative microbial stimulation seems reasonable for obtaining the most useful product. The aim of this study was the qualitative and quantitative analysis of humic acids during the composting of exogenous organic matter (EOM) of energy willow biomass (WBC) and biodegradable municipal waste (MSWC). Samples were collected at different maturity stages, and the following determinations were performed: total organic carbon (TOC) and total nitrogen (TN), carbon of fulvic (CFA) and humic (CHA) acids, carbon of residual fraction (CR), the elemental composition of humic acids, humification index (HR₁), and ω (oxidation) ratios. Results indicated the direction and intensity of biotransformation processes were determined by the availability of nitrogen compounds. The innovative use of microbial preparation has resulted in a more useful final product. Inoculation of lignocellulosic substrates stimulated the synthesis of humic acids, and the decomposition of the CR fraction, as well as HR₁ and ω ratios, may be used to assess the recycling efficiency. Full article

As a result of the energy crisis due, among other things, to climate change, most developed countries have taken steps with the main aim—among other things—of increasing the use of green energy sources that do not rely on fuels (including primarily liquid fuels) but use renewable energies. Plant biomass is a versatile substrate that can be used in many areas of the economy and production, but also for the production of various types of fuel. These range from rapeseed oil used as a component of biodiesel or maize starch for ethanol production to typically cellulosic plants such as energy willow, which can be used for direct combustion. The floodplain is home to this type of vegetation. It is characterized by great diversity in terms of geometric dimensions and mechanical and morphological properties. In addition, the location (easy access to water and sunlight) influences its potential energy value. Vegetation, thanks to favorable conditions, can achieve large weight gains in a relatively short period of time. Therefore, its properties should be carefully recognized in order to make more efficient use of energy and operating equipment used during harvesting. This paper presents an analysis of the changes in the elasticity of willow branches over a period of 16 days following harvesting. The changes were analyzed for branches taken from three different shrubs at three different plant height levels during the post-growth period. Based on the measurements carried out, the elastic modulus E of the shoots was estimated. The average modulus of elasticity ranged from about 4500 two days after cutting to about 5500 MPa 16 days after cutting and showed high variability, reaching even CV = 37%, both within a given shrub and depending on the measurement date. The results presented here indicate a high natural variability of mechanical parameters even within the same plant. Full article

This article presents a model to estimate the specific energy demand for cutting annual willow stems, considering variations in plant moisture content and sliding-cutting angles. The study involved laboratory tests and statistical analyses. Key parameters were measured for 50 randomly selected annual willow shoots, including total plant weight, leaf weight, stem weight, centre of gravity of the shoot, shoot length, and stem diameter at specified heights: 0, 150, 500, 750, 1000, 1250, 1500, and 2000 mm. Five levels of willow shoot moisture content were evaluated. The study established a cutting force-deformation relationship through strength tests with an accuracy of 1 N, which was subsequently used to calculate shear stress and specific cutting energy. Steel blades with an angle of 30° and sliding-cutting angles of 0°, 15°, 30°, and 45° were used in the study. Ten repetitions were performed for each combination of variable parameters: shoot moisture content and blade sliding-cutting angle. Experimental results were evaluated using analysis of variance (ANOVA), while Duncan’s test was applied to identify and classify groups with homogeneous specific energy values. The developed characterisation offers valuable information for designing shredding units and optimising their operational parameters to reduce energy consumption. Full article