Sugar Beet Residues Research Articles

Gross and Net Nitrogen Mineralization and Their Relationships with Microbial Biomass in a Volcanic Ash Soil and Alluvial Soil after Application of Crop Residues

ABSTRACT Nitrogen (N) release from crop residues is an important process which sustains the pool of available N in soils. Effects of application of the residues of sugar beet (Beta vulgaris L.) and wheat (Triticum aestivum L.) on gross and net N-mineralization and microbial biomass were investigated during incubation. The aim was to clarify how slower N release from crop residues relates to microbial biomass in Brown Andosols (BA; U.S. Soil Taxonomy: Andisols) compared to Brown Lowland soils (BL; U.S. Soil Taxonomy: Inceptisols). When microbial biomass N was increasing, gross N-mineralization rate was high and much inorganic N was actively immobilized. After reaching a maximum, the microbial biomass N was stable in BA, whereas microbial biomass N in BL treated with sugar beet residue decreased and inorganic N accumulated after 1 week incubation. In both soils treated with wheat residues, the microbial biomass N increased slowly for a long period due to lack of labile carbon (C), especially in BA which was able to hold a large microbial biomass. These findings suggest that factors other than low microorganism activity just after application of crop residues, such as the stability of synthesized biomass are important for the slow release of N from crop residues in volcanic ash soils.

Synergistic enhancement of the phytostabilization of a semiarid mine tailing by a combination of organic amendment and native microorganisms (Funneliformis mosseae and Bacillus cereus)

The goal of this work was to evaluate the effects of fermented sugar beet residue and inoculation with a native arbuscular mycorrhizal (AM) fungus, Funneliformis mosseae (Nicol. and Gerd.) Gerd. and Trappe, or a native bacterium, Bacillus cereus Frankland & Frankland, alone or in combination, on the establishment of Lygeum spartum L. seedlings grown in a mine tailing under semiarid conditions. We conducted a field study to analyse root and shoot dry biomass, shoot nutrient contents, mycorrhization, plant nitrate reductase (NR) and acid phosphomonoesterase activities, soil enzyme activities and aggregate stability. Ten months after field transplanting, it was found that the three experimental factors had interacted synergistically with regard to shoot and root biomass, with increases of about 410% and 370%, respectively relative to plants in the untreated soil. The treatment combining all three factors increased the root content of all heavy metals, and the levels of nitrogen (N), phosphorus, potassium and NR activity in shoot tissues, whereas it decreased root acid phosphomonoesterase activity. Soil dehydrogenase, protease and β-glucosidase activities, total N content and aggregate stability were increased by the combined treatment. In conclusion, the combination of the organic amendment, the native AM fungus and the native bacterium can be regarded as a suitable tool for phytostabilization with L. spartum due to its ability to enhance the tolerance of plants to heavy metals, improve the plant nutritional status and increase the soil microbial function related to the C cycling.

Optimizing the In-Vessel Composting Process of Sugarbeet Dry-Cleaning Residue

Rapid urbanization and industrialization around the world have created massive amounts of organic residues, which have been prioritized for conversion into valuable resources through the composting process to keep their harmful effect at a minimum. This research aimed to assess the influence of active and passive aeration on composting mass of sugar beet residues in the case of using additives (e.g., charcoal only or manure only or combination). Some physicochemical properties of composting mass were analyzed on certain days of composting. Some parameters including temperature–time profile, carbon to nitrogen ratio (C/N ratio), moisture content, electrical conductivity, pH, germination and microbial population enumeration of compost were measured. Cress germination test was conducted for each medium of germination which contains a mixture of soil and compost (at a ratio of 3:1) taken from each treatment. The results showed that temperature–time profile data of composting mass showed an irregularity. Forcedly aerated composting mass did not demonstrate a thermophilic phase while passively aerated ones did not show a mesophilic phase. Carbon to nitrogen (C/N) ratio reduction was greater in most forcedly aerated composting mass than passively aerated on days from 1 to 33 of composting period. The results further showed that electrical conductivity decreased at the end of the composting period where it ranged from 2.55 to 3.1 dS/m. Germination medium containing forcedly aerated compost treated with a combination of charcoal and manure achieved the highest germination index which was higher than the control sample by 58.63% followed by forcedly aerated composting mass treated by charcoal only which exceeded the control sample by 5.35%. Strong correlation coefficient (r > 0.80) for the relationship between germination index and number of bacteria was obtained on day 17th of composting period.

Mesoporous LaFeO3 nanoparticles decorated onto activated carbon from agricultural paste (Synthesis, characterization and adsorption properties)

This work reports study of structure, magnetic and adsorption properties of LaFeO3 nano particles decorated on the surface of activated carbon. Activated carbon was prepared from sugar beet residue as an agricultural waste material (ACS). The perovskite-type oxide LaFeO3 nanoparticles were prepared by sol-gel (pechini) method using citric acid. The LaFeO3 was decorated on the surface ACS. The structure of samples was studied by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). The surface morphology was considered by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) methods. The XRD results showed LaFeO3 nanoparticles have orthorhombic structure (space group continued to be Pnma. No. 62) of LaFeO3 perovskite did not change even when it was decorated onto ACS. VSM vibrating of samples was determined. The weak ferromagnetic behavior with specific saturation magnetization of 1.18 and 0.6 emu/g was observed at 15 kOe for LaFeO3 and LaFeO3 nanoparticles decorated onto ACS, respectively. Crystal violet (CV) dye was used as a model of pollutant. At contact time of 60 min and pH of 7 the highest percent of CV was observed. The maximum adsorption capacities of CV removal by ACS, LaFeO3 and LaFeO3 decorated on ACS was obtained, respectively. The adsorption kinetic of CV removal was followed by pseudo-second order model. Thermodynamic parameters of adsorption process of CV showed the endothermic and spontaneous processes. The LaFeO3 was decorated on the ACS was examined for real wastewater and 75% of dye removal was obtained.

Soil mulching and deficit irrigation effect on sustainability of nutrients availability and uptake, and productivity of maize grown in calcareous soils

ABSTRACT Plants are subjected to low use efficiency of water and nutrients in marginal lands such as calcareous soils. Moreover, plant wastes are not utilized optimally by the farmers. Hence, field trials were carried out in 2018 and 2019 summer seasons to find the practicable model which can be emerged through addition of sugar beet residues as mulching material and irrigation treatments in maize field. The amount of these residues were 0, 2.4, 7.2 and 12.0 ton ha−1 (denoted ‎ M0 M1 M2 and M3, respectively). Irrigation treatments were 60%, 80% and 100% of crop evapotranspiration (signed as W60, W80 and W100, respectively). The study was established in a strip plots design with three replications. Findings exhibited that W80 x M3 or M2 were as similar as W100 x M2 in improving biological, straw and grain yields ha−1. Similar beneficial effect of W100 or W80 on nutrient uptake was obtained under mulching soil with M3 or M2. Moreover, M1 x W80 or W100 achieved the maximally available phosphorus (P) in soil. As well, M3 x W80 showed stable improvement in water use efficiency during the two studied seasons. Due to irrigation and soil mulching combinations, calcium carbonate (CaCO3) was reduced by 5.6.1–32.6% compared to the initial CaCO3 in soil (25.42%). Generally, application of sugar beet residues at a rate of 7.2 ton ha−1 and moderate irrigation water supply, that is 80% of crop evapotranspiration may be considered a promising quixotic practice for regulating deficit irrigation in maize grown in calcareous soils. Continuous application of compatible irrigation regime and soil mulching, for example, 80% of crop evapotranspiration plus soil mulching could have the potentiality to improve calcareous soil properties year after year.

Biogas feedstock potentials and related water footprints from residues in China and the European Union

China encounters heavy air pollution caused by coal consumption. China and the EU aim to decrease greenhouse gas emissions. Shifting to biogas from residues contributes to solving both problems. This study assesses China's biogas potentials and related water footprints (WFs) and compares results with potentials and WFs for the EU. Starting from a literature review on EU biogas potentials, it analyzes information resulting in a calculation methodology, its validation and application to China. Finally, it estimates WFs and makes a comparative assessment of biogas potentials of the EU and China. In the EU, biogas from agricultural, forestry and other residues might contribute 8% (5300 PJ) to primary energy consumption, in China 10% (13,275 PJ.) In the EU, agriculture contributes 41%, forestry 26%, other residues 23%, and manure 10%. The corresponding results for China are agriculture (67%), forestry (23%), manure (7%) and other residues (3%). In the EU, biogas might contribute 45% to total gas demand; in China more biogas can be produced than consumed in 2018 (185% of demand). The EU results fall in the range of residue potentials from earlier studies. Maize, wheat, barley and rapeseed contribute 78% to the EU agricultural biogas potential. In China, dominant crops are maize (49%), rice (18%), wheat (12%) and seed cotton (6%). For water, there are large differences among WFs of specific crop residues, but also between WFs for EU and Chinese crop residues. Most Chinese crop residues have larger WFs than the EU residues. Biogas from sugar beet residues has the smallest WFs, biogas from tobacco residues the largest. Although using residues for energy does not change total national WFs, it reallocates WFs over main products and residues. The comparative assessment supports better use of biogas potentials from residues with lower WFs and is also applicable for other regions and countries.

Synthesis and characterization of activated carbon from sugar beet residue for the adsorption of hexavalent chromium in aqueous solutions.

A series of micro–mesoporous activated carbons (ACs) were prepared from sugar beet residue by a two-step method including KOH chemical activation and were used for Cr(vi) removal from aqueous solutions. Several characterization techniques, including SEM, TEM, N2 adsorption, XRD, FTIR, and Raman spectroscopy, were used to determine the chemical and physical characteristics of the ACs, and the adsorption properties of the ACs were tested. The results indicated that the high specific surface area of the ACs reached 2002.9 m2 g−1, and the micropore surface area accounts for 85% of the total area. The optimal conditions for achieving the maximum Cr(vi) adsorption capacity of 163.7 mg g−1 by the ACs were activation with a KOH/carbon ratio of 3.0, an initial Cr(vi) concentration of 400 mg L−1, an adsorbent dose of 2.0 g L−1 and pH of 4.5. Therefore, the ACs exhibit excellent adsorption performance for removing Cr(vi) from aqueous solutions. According to an investigation of the adsorption process, the adsorption isotherm is most consistent with the Langmuir isotherm model, and the adsorption kinetics were well described by the pseudo-second-order model.

Conversion of sugar beet residues into lipids by Lipomyces starkeyi for biodiesel production

BackgroundLipids from oleaginous yeasts emerged as a sustainable alternative to vegetable oils and animal fat to produce biodiesel, the biodegradable and environmentally friendly counterpart of petro-diesel fuel. To develop economically viable microbial processes, the use of residual feedstocks as growth and production substrates is required.ResultsIn this work we investigated sugar beet pulp (SBP) and molasses, the main residues of sugar beet processing, as sustainable substrates for the growth and lipid accumulation by the oleaginous yeast Lipomyces starkeyi. We observed that in hydrolysed SBP the yeast cultures reached a limited biomass, cellular lipid content, lipid production and yield (2.5 g/L, 19.2%, 0.5 g/L and 0.08 g/g, respectively). To increase the initial sugar availability, cells were grown in SBP blended with molasses. Under batch cultivation, the cellular lipid content was more than doubled (47.2%) in the presence of 6% molasses. Under pulsed-feeding cultivation, final biomass, cellular lipid content, lipid production and lipid yield were further improved, reaching respectively 20.5 g/L, 49.2%, 9.7 g/L and 0.178 g/g. Finally, we observed that SBP can be used instead of ammonium sulphate to fulfil yeasts nitrogen requirement in molasses-based media for microbial oil production.ConclusionsThis study demonstrates for the first time that SBP and molasses can be blended to create a feedstock for the sustainable production of lipids by L. starkeyi. The data obtained pave the way to further improve lipid production by designing a fed-batch process in bioreactor.Graphical abstract

Comparative assessment of bioethanol supply chain: insights from Iran

Biofuels are important alternative fuel in recent years. In this work, the bioethanol supply chain planning is performed by BioEnergy Supply Model to optimally find the best pathways using economic and environmental objective functions in Iran. Then, different sustainability criteria focusing on environmental, economic, and social concerns are assessed for possible routes of the bioethanol production from available resources. Although agriculture residues and wastes, decrease the greenhouse gas emissions but municipal solid wastes are more economic and require less water. The agricultural wastes and residues improve the sustainability. Then, criteria focusing on environmental, economic, and social concerns are assessed for available agricultural resources. The most cost-intensive bioethanol is obtained from the rice and barley wastes with 52.6 and 42.4 billion dollars over 25 years, respectively. The lowest total cost of the supply chain belongs to sugarcane and sugar beet wastes with the amounts of 10.7 and 13.56 billion dollars, respectively. The bioethanol form wastes of rice, barely, and wheat cultivation mitigates the global warming more than other resources while they have negative carbon cycles. Similarly, the highest and lowest number of created jobs of bioethanol supply chain belong to the rice wastes and the sugar beet and corn residues.

Use of laboratory incubation techniques to estimate greenhouse gas footprints from conventional and no-tillage organic agroecosystems

Organic agroecological systems “produce goods using methods that preserve the environment” but can be a substantial source of greenhouse gases (GHG) if not managed properly. The objective of this experiment was to monitor nitrogen (N) and carbon (C) transformations in soils resulting from N additions, water filled pore space (WFPS) and prior tillage management during a simulated freeze-thaw. Incubated soils were taken from two USDA certified organic five-year small grain rotations with mixed legume cover crops that varied only in tillage, conventional (CT) vs. no-tillage (NT) for 3 yr prior to sampling. Soils incubated for 149 d were left unamended or amended with 15N labelled urea or sugar beet residue and maintained at 40, 60 and 80% WFPS. Non-metric multidimensional scaling (NMS) verified that soils amended with beet vs urea clustered separately in ordination space. A two way PerMANOVA analysis confirmed a significant interaction between WFPS and N amendment (p = 0.0002). Prior tillage management, N treatment and WFPS had a significant effect on GHG emission from soils. At 40% WFPS, soil previously in NT amended with beet residues emitted more nitrous oxide (N2O) and carbon dioxide (CO2) relative to soil previously in CT. At 60% WFPS, soil previously in CT amended with beet residues emitted greater N2O and less CO2 relative to soil previously in NT. Our research indicates that climate, carbon stocks and duration of prior tillage management determined the potential of no-till to reduce GHG emissions during a simulated freeze-thaw. Growers should note that as much as 4.51% of nitrates (NO3−) in residues can be lost as N2O at an average soil temperature of 10 °C.

Highly redispersible sugar beet nanofibers as reinforcement in bionanocomposites

A simple method for preparing redispersible nanofibers from sugar beet residue and their use as a well-dispersed reinforcement for a polyvinyl alcohol (PVA) matrix is reported. It is known that the redispersion of dried cellulose nanofibers is difficult because of the formation of strong hydrogen bonds between the nanofibers. The results show that the properties of the initial sugar beet nanofiber suspension can be recovered without the use of chemical modification or additives with higher pectin and hemicellulose content. Undried and redispersed nanofibers with and without pectin were used as nanocomposite reinforcement with PVA. The redispersed nanofibers were as good reinforcements as the undried nanofibers. The tensile strength and elastic modulus of the nanocomposites with the redispersed sugar beet nanofibers were as good as those of the nanocomposites with undried nanofibers. Interestingly, the nanofiber dispersion in the PVA matrix was better when sugar beet nanofibers containing pectin and hemicellulose were used as reinforcements.

Use of biological indicators of soil health to estimate reactive nitrogen dynamics in long-term organic vegetable and pasture systems

Diverse crop rotations, cover crops and the possibility of integrating livestock make organic systems potentially more sustainable than other agroecosystems. Lower reactive nitrogen (N) in organic systems minimizes the potential for N losses. However, addition of organic manures and residues containing mineralizable N and carbon (C) have the potential to enhance nitrous oxide (N2O) emissions. We conducted a 39 d laboratory incubation to assess key microbiological drivers controlling nitrification and denitrification in long-term organic agroecosystems during simulated freeze-thaw cycles. Soils were collected from two annual organic vegetable systems receiving 1) mixed-compost, or 2) broiler litter and 3) an organic perennial pasture system cropped to vegetables every third year. Soil microcosms amended with 15N labelled sugar beet residue or unamended were maintained at 40, 60 and 80% of water filled pore space (WFPS). Significant N2O was emitted (4287–6138 μg kg−1soil) via denitrification from amended soil microcosms at 3 °C and 80% WFPS. Archaeal (AOA) and bacterial (AOB) nitrifier amoA gene copies were affected by temperature and reactive N species during freeze-thaws. Long-term organic vegetable cropping systems receiving mixed-compost additions had the potential to accumulate C and immobilize excess reactive soil N (particularly nitrates) thereby improving soil health and reducing N2O emissions.

Production of Adipic Acid from Sugar Beet Residue by Combined Biological and Chemical Catalysis

AbstractAdipic acid is one of the most important industrial dicarboxylic acids and is used mainly as a precursor to nylon‐6,6. Currently, commercial adipic acid is produced primarily from benzene by a chemical route that is associated with environmental, health, and safety concerns. Herein, we report a new process to produce adipic acid from an inexpensive renewable feedstock, sugar beet residue by combining an engineered Escherichia coli strain and Re‐based chemical catalysts. The engineered E. coli converted d‐galacturonic acid to mucic acid, which was precipitated easily with acid, and the mucic acid was further converted to adipic acid by a deoxydehydration reaction catalyzed by an oxorhenium complex followed by a Pt/C‐catalyzed hydrogenation reaction under mild conditions. A high selectivity to the free acid products was achieved by tuning the acidity of the Re‐based catalysts. Finally, adipic acid was produced directly from sugar beet residue that was hydrolyzed enzymatically with engineered E. coli and two chemical catalysts in a yield of 8.4 %, which signifies a new route for the production of adipic acid.

Suitability of the microbial community composition and function in a semiarid mine soil for assessing phytomanagement practices based on mycorrhizal inoculation and amendment addition

The recovery of species composition and functions of soil microbial community of degraded lands is crucial in order to guarantee the long-term self-sustainability of the ecosystems. A field experiment was carried out to test the influence of combining fermented sugar beet residue (SBR) addition and inoculation with the arbuscular mycorrhizal (AM) fungus Funneliformis mosseae on the plant growth parameters and microbial community composition and function in the rhizosphere of two autochthonous plant species (Dorycnium pentaphyllum L. and Asteriscus maritimus L.) growing in a semiarid soil contaminated by heavy metals. We analysed the phospholipid fatty acids (PLFAs), neutral lipids fatty acids (NLFAs) and enzyme activities to study the soil microbial community composition and function, respectively. The combined treatment was not effective for increasing plant growth. The SBR promoted the growth of both plant species, whilst the AM fungus was effective only for D. pentaphyllum. The effect of the treatments on plant growth was linked to shifts in the rhizosphere microbial community composition and function. The highest increase in dehydrogenase and β-glucosidase activities was recorded in SBR-amended soil. The SBR increased the abundance of marker PLFAs for saprophytic fungi, Gram+ and Gram− bacteria and actinobacteria, whereas the AM fungus enhanced the abundance of AM fungi-related NLFA and marker PLFAs for Gram− bacteria. Measurement of the soil microbial community composition and function was useful to assess the success of phytomanagement technologies in a semiarid, contaminated soil.

Natural Organic Amendments for Improved Phytoremediation of Polluted Soils: A Review of Recent Progress

Environmental pollution caused by metals, radionuclides and organic pollutants affects quality of the biosphere: soil, water and air. Currently, great efforts have been made to reduce, remove or stabilize contaminants in polluted sites. There has been increasing interest in phytoremediation—the use of plants to reduce concentration of pollutants or to render them harmless. This paper provides a brief review of recent progress in the research and practical application of phytoremediation techniques. Improvements in phytoremediation due to utilization of organic amendments, namely, agro- and industrial wastes (such as sugar beet residue, composted sewage sludge or molasses), biochar, humic substances, plant extracts and exudates are discussed, as well as their influences on soil structure and characteristics, plants growth and bioavailability of pollutants. Both plant-assisted phytoremediation and the use of natural materials in the absence of remediating plant are believed to be cost-effective and environmentally friendly approaches for soil cleanup. However, the characterization and quantification of a range of natural materials used in phytoremediation are essential in order to implement these approaches to practice.

Interactive effect between Cu‐adapted arbuscular mycorrhizal fungi and biotreated agrowaste residue to improve the nutritional status of Oenothera picensis growing in Cu‐polluted soils

AbstractThe interactive effect of sugar beet (SB) agrowaste and arbuscular mycorrhizal (AM) fungi inoculation in response to increasing Cu levels was evaluated in the metallophyte Oenothera picensis. Plants were grown in a Cu‐added soil (0, 100, or 500 mg Cu kg−1), in presence or absence of SB, and inoculated with: (1) indigenous Cu adapted mycorrhiza (IM) isolated from Cu‐polluted soils; (2) Claroideoglomus claroideum (CC); or (3) maintained uninoculated (control). Sugar beet application produced an increase in shoot biomass of 2 to 7 times, improving plant nutritional status and allowing their survival at the highest Cu concentrations. Moreover, AM fungi utilization had a positive effect promoting the plant establishment; nevertheless, Cu plant concentration as well as the mycorrhizal development in terms of AM colonization, AM spore density, and glomalin production were strictly dependent of the AM fungi strains used. Remarkable differences between AM fungi strains were observed at the highest soil Cu level where only plants colonized by IM were able to survive and grow when no SB residue was added. An interactive effect between AM fungi and SB produced a higher plant growth than plants without the amendment application, improving the plant establishment and allowing their survival at highest copper concentrations, suggesting that this combination could be used as a biotechnological tool for the phytoremediation of Cu‐polluted soils.

Selection of Plant Species–Organic Amendment Combinations to Assure Plant Establishment and Soil Microbial Function Recovery in the Phytostabilization of a Metal-Contaminated Soil

A mesocosm experiment was established to evaluate the effect of two organic wastes: fermented sugar beet residue (SBR) and urban waste compost on the stimulation of plant growth, phytoaccumulation of heavy metals (HM) and soil biological quality and their possible use in phytostabilization tasks with native (Piptatherum miliaceum, Retama sphaerocarpa, Bituminaria bituminosa, Coronilla juncea and Anthyllis cytisoides) and non-native (Lolium perenne) plants in a heavy metal-contaminated semiarid soil. Except R. sphaerocarpa, SBR increased the contents of shoot N, P and K and shoot biomass of all plants. The percentage of mycorrhizal colonization was not affected by the organic amendments. The highest increase in dehydrogenase and β-glucosidase activities was recorded in SBR-amended P. miliaceum. SBR decreased toxic levels of HM in shoot of P. miliaceum, mainly decreasing Fe and Pb uptake to plants. This study pointed out that the SBR was the most effective amendment for enhancing the plant performance and for improving soil quality. The combination of SBR and P. miliaceum can be regarded the most effective strategy for being employed in phytostabilization projects of this contaminated site.

Microbial inoculants and organic amendment improves plant establishment and soil rehabilitation under semiarid conditions

The re-establishment of autochthonous shrub species is an essential strategy for recovering degraded soils under semiarid Mediterranean conditions. A field assay was carried out to determine the combined effects of the inoculation with native rhizobacteria (Bacillus megaterium, Enterobacter sp, Bacillus thuringiensis and Bacillus sp) and the addition of composted sugar beet (SB) residue on physicochemical soil properties and Lavandula dentata L. establishment. One year after planting, Bacillus sp. and B. megaterium + SB were the most effective treatments for increasing shoot dry biomass (by 5-fold with respect to control) and Enterobacter sp + SB was the most effective treatments for increasing dry root biomass. All the treatments evaluated significantly increased the foliar nutrient content (NPK) compared to control values (except B. thuringiensis + SB). The organic amendment had significantly increased available phosphorus content in rhizosphere soil by 29% respect to the control. Enterobacter sp combined with sugar beet residue improved total N content in soil (by 46% respect to the control) as well as microbiological and biochemical properties. The selection of the most efficient rhizobacteria strains and their combined effect with organic residue seems to be a critical point that drives the effectiveness of using these biotechnological tools for the revegetation and rehabilitation of degraded soils under semiarid conditions.

Evaluation of the phytomass source for composite preparation

AbstractThe properties of lignocellulose materials from the trunk and bark of trees, and from agricultural sources were investigated by thermogravimetry (TG) and pyrolysis–gas chromatography/mass spectrometry (Py‐GC/MS). The goal was to learn which of the phytomass sources is the most accessible to dehydration and aldol reactions, and in this way could be considered suitable for composite preparation by the thermal pressing treatment. The bagasse second differential thermal analysis peak in air is at the highest temperature acceptable for intermolecular dehydration/crosslinking, and therefore we consider bagasse to be the most suitable candidate for composite preparation. From the TG results in air at 250°C, it follows that willow wood and bagasse are the most thermally resistant sources. The data obtained by Py‐GC/MS analysis showed glycolaldehyde and acetic acid as dominant markers related to adhesion properties via aldol condensation. The detected sum amount of glyceraldehyde and acetic acid decreases in the order: beech wood > bagasse > acacia wood > sugar beet pulp, whereas the remaining species produced much less of it. By comparing results run at above conditions with composite preparation using the pressing thermal treatment at a temperature of 150°C and pressures up to 800 kPa, the suggested evaluation was examined for application on sugar beet residue. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effects of Water Stress, Organic Amendment and Mycorrhizal Inoculation on Soil Microbial Community Structure and Activity During the Establishment of Two Heavy Metal-Tolerant Native Plant Species

Our aim was to examine the effect of water stress on plant growth and development of two native plant species (Tetraclinis articulata and Crithmum maritimum) and on microbial community composition and activity in the rhizosphere soil, following the addition of an organic amendment, namely sugar beet residue (SBR), and/or the inoculation with an arbuscular mycorrhizal (AM) fungus, namely Glomus mosseae, in a non-sterile heavy metal-polluted soil. The AM inoculation did not have any significant effect on plant growth of both species. In T. articulata, SBR increased shoot growth, foliar P, total phospholipid fatty acids (PLFA), fungi-related PLFA, AM fungi-related neutral lipid fatty acid, bacterial gram-positive/gram-negative PLFA ratio and the β-glucosidase and dehydrogenase activities. SBR and AM inoculation increased phosphatase activity in T. articulata plants grown under drought conditions. In both plants, there was a synergistic effect between AM inoculation and SBR on mycorrhizal colonisation under drought conditions. In C. maritimum, the increase produced by the SBR on total amounts of PLFA, bacterial gram-positive-related PLFA and bacterial gram-negative-related PLFA was considerably higher under drought conditions. Our results suggest that the effectiveness of the amendment with regard to stimulating microbial communities and plant growth was largely limited by drought, particularly for plant species with a low degree of mycorrhizal colonisation.