Composition, Ageing and Herbicidal Properties of Wood Vinegar Obtained through Fast Biomass Pyrolysis

Optimizing Cucumis sativus seedling vigor: the role of pistachio wood vinegar and date palm compost in nutrient mobilization

BACKGROUND

The goal of this research is to enhance the quality of cucumber seedlings grown in greenhouses by experimenting with various soilless culture mediums (CMs) and the application of pistachio wood vinegar (WV). The experimental setup was designed as a factorial experiment within a randomized complete block design (RCBD), in greenhouse conditions featuring three replications to assess the effects of different culture media (CMs) and concentrations of pistachio wood vinegar (WV) on cucumber seedling growth. Cucumber seeds were planted in three CMs: coco peat-peat moss, coco peat-vermicompost, and date palm compost-vermicompost mixed in a 75:25 volume-to-volume ratio. These were then treated with pistachio WV at concentrations of 0, 0.5, and 1%, applied four times during irrigation following the emergence of the third leaf.

RESULTS

The study revealed that treating seedlings with 0.5% WV in the date palm compost-vermicompost CM significantly enhanced various growth parameters. Specifically, it resulted in a 90% increase in shoot fresh mass, a 59% increase in shoot dry mass, an 11% increase in root fresh mass, a 36% increase in root dry mass, a 65% increase in shoot length, a 62% increase in leaf area, a 25% increase in stem diameter, a 41% increase in relative water content (RWC), and a 6% improvement in membrane stability index (MSI), all in comparison to untreated seedlings grown in coco peat-peat moss CM. Furthermore, chlorophyll a, b, total chlorophyll, and carotenoid levels were 2.3, 2.7, 2.6, and 2.7 times higher, respectively, in seedlings treated with 0.5% WV and grown in the date palm compost-vermicompost CM, compared to those treated with the same concentration of WV but grown in coco peat-peat moss CM. Additionally, the Fv/Fm ratio saw a 52% increase. When plant nutrition was enhanced with the date palm compost-vermicompost CM and 1% WV, auxin content rose by 130% compared to seedlings grown in coco peat-peat moss CM and treated with 0.5% WV.

CONCLUSIONS

The study demonstrates that using 0.5% WV in conjunction with date palm compost-vermicompost CM significantly betters the quality of cucumber seedlings, outperforming other treatment combinations.

The Potential of Wood Vinegar to Replace Antimicrobials Used in Animal Husbandry-A Review

The indiscriminate use of antimicrobials in animal husbandry can result in various types of environmental contamination. Part of the dose of these products is excreted, still active, in the animals' feces and urine. These excreta are widely used as organic fertilizers, which results in contamination with antimicrobial molecules. The impacts can occur in several compartments, such as soil, groundwater, and surface watercourses. Also, contamination by antimicrobials fed or administrated to pigs, chickens, and cattle can reach the meat, milk, and other animal products, which calls into question the sustainability of using these products as part of eco-friendly practices. Therefore, a search for alternative natural products is required to replace the conventional antimicrobials currently used in animal husbandry, aiming to mitigate environmental contamination. We thus carried out a review addressing this issue, highlighting wood vinegar (WV), also known as pyroligneous acid, as an alternative antimicrobial with good potential to replace conventional products. In this regard, many studies have demonstrated that WV is a promising product. WV is a nontoxic additive widely employed in the food industry to impart a smoked flavor to foods. Studies have shown that, depending on the WV concentration, good results can be achieved using it as an antimicrobial against pathogenic bacteria and fungi and a valuable growth promoter for poultry and pigs.

Semi-VOCs of Wood Vinegar Display Strong Antifungal Activities against Oomycete Species Globisporangium ultimum and Pythium aphanidermatum

Plant disease outbreaks are increasingly exacerbated by climate change and the conditions of stress combinations. They are negatively affecting crop yield and driving threats to food security in many areas of the world. Although synthetic pesticides offer relative success in the control of pests and plant diseases, they are often overused, and this method faces numerous drawbacks, including environmental toxicity, soil degradation, and adverse effects on human health. Therefore, alternatives are being developed and examined, including the biocontrol of pests and pathogens and biomass pyrolysis leading to wood vinegar that has shown great promise in agriculture and organic farming. However, while wood vinegar use is expanding and allows the control of numerous pests and bacterial and fungal diseases, its application to control oomycete diseases is limited. This study aimed to test wood vinegar for the control of oomycete plant pathogens from which six wood vinegars of pistachio, pomegranate, almond, pine, cypress, and walnut were produced. The inhibitory effects of volatile metabolites (semi-VOCs) of different wood vinegars concentrations (100%, 50%, 25%, 12.5%, and 6.25%) were examined against the hyphal growth of Globisporangium ultimum and Pythium aphanidermatum isolates. An in vitro analysis unambiguously demonstrated that for Globisporangium ultimum, the wood vinegar semi-VOCs of almond, pistachio (C 100% and 50%), and walnut (C 100%) totally inhibited mycelial growth. On the other hand, Pythium aphanidermatum, pistachio (C 100%, 50%, and 25%), and cypress (C 100%) expressed their abilities to completely inhibit the mycelial growth. Other treatments, including relevant concentrations of pine and pomegranate significantly inhibited the growth of mycelia of both species compared to the control (p ≤ 0.05). Therefore, wood vinegar could be considered a natural and organic product to use in agriculture to cope not only against pests, bacterial and fungal pests but also against emerging oomycete plant diseases.

Pyroligneous acids from biomass charcoal by-product as a potential non-selective bioherbicide for organic farming: its chemical components, greenhouse phytotoxicity and field efficacy

Effective and environmentally friendly herbicides are urgently needed to meet consumer demand for organic products. To evaluate the weed control effect of four pyroligneous acid (PAs) mixtures, the byproducts of bamboo/wood/straw vinegar, two herbicide discovery tests were done: (1) the greenhouse tests by using four indicative plants: wheat (Triticum sativa), radish (Raphanus sativus), cucumber (Cucumus sativus), and Echinochloa crusgalli (L.) Beauv; (2) Field trials with four weeds: E. crusgalli, Eleusine indica (L.) Gaertn, Alternanthera philoxeroides (Mart.) Griseb, and Conyza canadensis (L.) Cronq. Greenhouse tests showed that the efficacy of PAs and acetic acid (AA) to control four test plants increased with the increasing of PAs concentration. The inhibition rates of four tested PAs (FBV (0.6-9.2% AA + (0.3-5.0% tar), HWV (0.2-1.8% AA + 0.3-4.3% tar), ASV (0.5-8.7% AA + 0.4-7.0% tar), and CWV (0.7-5.3% AA + 0.5-7.5% tar) gave inhibition rates of 56 ± 4-97 ± 2%, 21 ± 2-90 ± 6%, 29 ± 3-98 ± 5%, and 44 ± 6-86 ± 2%, respectively, and the field effects of PAs against four weeds were enhanced with the increasing of concentrations and time after spraying (1 to 14 days). Their control effects against E. crusgalli, E. indica, A. philoxeroides, and C. canadensis were 4 ± 1-93 ± 4%, 7 ± 3-90 ± 3%, 32 ± 2-95 ± 3%, and 31 ± 5-96 ± 4%, respectively. The mixed effect of the four PAs was higher than the same dose of AA. These results will help to determine the potential of PAs to be developed as non-selective herbicides to control weeds in organic farming.

Sustainable Plant Growth Promotion and Chemical Composition of Pyroligneous Acid When Applied with Biochar as a Soil Amendment

The pyrolysis of biomass material results in pyroligneous acid (PA) and biochar, among other by-products. In agriculture, PA is recognized as an antimicrobial agent, bio-insecticide, and bio-herbicide due to antioxidant activity provided by a variety of constituent materials. Application of PA to crop plants and soil can result in growth promotion, improved soil health, and reduced reliance on polluting chemical crop inputs. More detailed information regarding chemical compound content within PA and identification of optimal chemical profiles for growth promotion in different crop species is essential for application to yield effective results. Additionally, biochar and PA are often applied in tandem for increased agricultural benefits, but little is known regarding the optimal proportion of each crop input. This work reports on the effect of combined applications of different proportions of PA (200- and 800-fold dilutions) and chemical fertilizer rates (100%, 75%, 50%, and 0%) in the presence or absence of biochar on Komatsuna (Brassica rapa var. perviridis, Japanese mustard spinach) plant growth. To elucidate the chemical composition of the applied PA, four different spectroscopic measurements of fluorescence excitation were utilized for analysis—excitation-emission matrix, ion chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. It was determined that PA originating from pyrolysis of Japanese pine wood contained different classes of biostimulants (e.g., tryptophan, humic acid, and fulvic acid), and application to Komatsuna plants resulted in increased growth when applied alone, and in different combinations with the other two inputs. Additionally, application of biochar and PA at the higher dilution rate increased leaf accumulation of nutrients, calcium, and phosphorus. These effects reveal that PA and biochar are promising materials for sustainable crop production.

Effects of Biochar on Biointensive Horticultural Crops and Its Economic Viability in the Mediterranean Climate

The effects of biochar on different horticultural crops (lettuce, tomato, sweet pepper, and radish) were evaluated in the Mediterranean climate. Biochar was produced by pyrolysis of Pinus pinaster wood chips at 550 °C and used at 1 (B1) and 2 (B2) kg/m2 application rates on six 3.5 m2 plots in each treatment, with two control plots (B0). No fertilizer was used. Treatment B1 led to a significant increase (p < 0.01) of 35.4%, 98.1%, 28.4%, and 35.2% in the mean fresh weight of radishes, lettuce, tomatoes, and sweet peppers, respectively. Treatment B2 resulted in an improvement of 70.7% in radishes, 126.1% in lettuce, 38.4% in tomatoes, and 95.0% in sweet peppers (p < 0.01). Significant differences between treatments B1 and B2 were observed in the radish, tomato, and sweet pepper crops but not in lettuce. The profitability of biochar application to these crops was studied by considering a biochar price of 800 EUR/t and applying a CO2 fixation subsidy, assuming the updated February 2022 price (90 EUR/t). In lettuce, tomato, and sweet pepper crops, the investment payback period was approximately one year. Application of biochar generated economic benefit either from the first harvest or in the second year. In radish, this period was longer than two years; however, an increase in the annual frequency of cultivation should be studied to optimize the benefit. The dose that provided the greatest benefit was B1 (for all crops, except for sweet pepper). Biochar considerably improved fruit and vegetable yield under the Mediterranean climate; however, further studies are needed to assess the effects of biochar on soil properties and yield to estimate long-term environmental and economic benefits.

Influence of Specific Power on the Solid and Liquid Products Obtained in the Microwave-Assisted Pyrolysis of End-of-Life Tires

In this work, chemical recycling as an alternative to conventional end-of-life treatments was studied. Two different types of end-of-life tires (ELT), truck tires and mix tires (50:50 mixture of passenger car and truck tires), were pyrolyzed in a batch microwave reactor. The influence of specific power (10, 20, and 30 W/g) on mass distribution was analyzed. The maximum liquid yield was attained at 10 W/g, while the maximum gas yield is obtained at 30 W/g. Liquid fractions were characterized by gas chromatography/quadrupole mass spectrometry (GC/qMS) to identify the main components, and major compounds were quantified. In all samples, limonene (3.76 ± 0.31–6.80 ± 2.37 wt. %) and BTEX (3.83 ± 0.20–1.19 ± 2.80 wt. %) were the main components. Major limonene concentration is obtained in oil produced from truck ELT while higher yields of aromatic compounds are obtained from mix ELT. The maximum BTEX concentration is obtained at 10 W/g being toluene the main compound with a concentration of 2.07 ± 0.42 and 4.63 ± 1.29 for truck and mix ELT, respectively. The separation and purification of these compounds will confer important value to these fractions. Higher yields of the solid fraction are produced when mix tires are pyrolyzed due to the higher concentration of ash in this type of ELT. Recovered carbon black was characterized by measuring the surface area.

Valorization of rubberwood sawdust and sewage sludge by pyrolysis and co-pyrolysis using agitated bed reactor for producing biofuel or value-added products

This study investigated experimentally pyrolysis of rubberwood sawdust (RWS), sewage sludge (SS), and their blends (25:75, 50:50, and 75:25 by weight) in an agitated bed pyrolysis reactor. The yields and characteristics of liquid product and biochar were determined for pyrolysis at 450, 500, and 550 °C and were affected both by temperature and feedstock type. The liquid and biochar yields were in the ranges 27.30-52.42 and 21.43-49.66 (wt%). Pyrolysis of RWS at 550 °C provided the highest liquid yield, while SS gave a high biochar yield. Co-pyrolysis of SS with RWS improved yield and quality of liquid and biochar products. The liquid product had 57.54-70.70 wt% of water and a low hydrocarbon content. The higher heating value (HHV) of water-free liquid product was 14.73-22.45 MJ/kg. The major compounds of liquid product included acetic acid, 2-propanone, 1-hydroxy, and phenols according to GC-MS. The biochar from RWS had a high carbon content (83.37 wt%) and a high HHV (33.57 MJ/kg), while SS biochar was mainly ash (67.62 wt%) with low carbon content. The SS biochar also had high contents of Si, Ca, Fe, K, and Mg as determined by XRF. Co-pyrolysis of SS with RWS improved the biochar by increasing its carbon content and reducing ash and inorganic elements. The surface of RWS biochar was more porous, while SS biochar had the larger specific surface according to SEM and BET. Based on these results, co-pyrolysis of 75:25 feedstock mix is recommended for further studies on applications of liquid product and biochar.

Effects and Economic Sustainability of Biochar Application on Corn Production in a Mediterranean Climate

The effects of two types of biochar on corn production in the Mediterranean climate during the growing season were analyzed. The two types of biochar were obtained from pyrolysis of Pinus pinaster. B1 was fully pyrolyzed with 55.90% organic carbon, and B2 was medium pyrolyzed with 23.50% organic carbon. B1 and B2 were supplemented in the soil of 20 plots (1 m2) at a dose of 4 kg/m2. C1 and C2 (10 plots each) served as control plots. The plots were automatically irrigated and fertilizer was not applied. The B1-supplemented plots exhibited a significant 84.58% increase in dry corn production per square meter and a 93.16% increase in corn wet weight (p << 0.001). Corn production was no different between B2-supplemented, C1, and C2 plots (p > 0.01). The weight of cobs from B1-supplemented plots was 62.3%, which was significantly higher than that of cobs from C1 and C2 plots (p < 0.01). The grain weight increased significantly by 23% in B1-supplemented plots (p < 0.01) and there were no differences between B2-supplemented, C1, and C2 plots. At the end of the treatment, the soil of the B1-supplemented plots exhibited increased levels of sulfate, nitrate, magnesium, conductivity, and saturation percentage. Based on these results, the economic sustainability of this application in agriculture was studied at a standard price of €190 per ton of biochar. Amortization of this investment can be achieved in 5.52 years according to this cost. Considering the fertilizer cost savings of 50% and the water cost savings of 25%, the amortization can be achieved in 4.15 years. If the price of biochar could be reduced through the CO2 emission market at €30 per ton of non-emitted CO2, the amortization can be achieved in 2.80 years. Biochar markedly improves corn production in the Mediterranean climate. However, the amortization time must be further reduced, and enhanced production must be guaranteed over the years with long term field trials so that the product is marketable or other high value-added crops must be identified.

Herbicidal effects of wood vinegar on nitrophilous plant communities

In Europe, and many parts of the world, the number and variety of animal species on farmland is in marked decline. There is a need to search for alternatives that are safe for the environmental and are effective in controlling weeds. Wood vinegar from biomass pyrolysis may be an alternative for herb control. In this study, Wood vinegar (WV) pH, moisture content, and composition were analyzed, with subsequent assessment of the effects of WV on nitrophilous plant communities under natural conditions. The following three treatments were used: WV dissolved in water to form 25 vol% and 50 vol% dilutions and undiluted WV (100 vol%). The results showed a greater than 70% decrease in biomass at 7 days after WV application in all treatments. At the end of the sampling period (day 42), the plots treated with WV had four-times less biomass than the controls. No significant differences were observed among different treatments, thus indicating that a 25% dilution may suffice for use as an herbicide. However, this concentration also produced the highest variability in results. The area cleared by the affected species was colonized by perennial species. At the end of the sampling, 80% of the area of the treated plots was occupied by perennial species, whereas this percentage was 30% in control plots. Electron micrographs showed that the epidermis of the treated plants was severely affected within a few hours of the treatment, particularly of the stomatal cells. The most affected species were those with smooth leaves without protective structures and those with lighter stems and leaves. The good herbicidal performance of WV notwithstanding, regulations must be clarified for its use as an herbicide.