Wheat Straw Stem Research Articles

Wheat straw biorefinery for agricultural waste valorisation

This study justifies strategies for a new concept of agricultural waste management prior to biorefinery, based on comprehensive materials science investigations. Efficient pretreatments for the extraction, separation and fractionation of agricultural waste in conjunction with understanding of the details of its microstructure and properties can be essential for high-efficiency biorefinery. The information in this study will serve as a valuable and fundamental basis for researchers and industries in the sector of straw biomass biorefinery. In order to achieve the maximum efficiency possible in agricultural waste valorisation, it is crucial to understand that not all parts of the straw are equally valuable and can be treated in the same biorefinery process. In this study, the wheat straw stem, which is composed of nodes and internodes, has been shown to have distinct properties and characteristics. Separation of these anatomical parts before the biorefinery process presents a unique area for future research investment, as it can lead to higher performance of the intended product. For example, the node has higher extractives and ash content, which prove to be a diminishing factor for biocomposite or bioenergy production.

Survey of wheat straw stem characteristics for enhanced resistance to lodging

Lodging is one of the major constraints that threaten crop productivity. Although the relationship between cell walls and straw strength has been well recognized, little relevant research has been done in wheat, particularly on the monomer composition and structural characteristics of cell wall polymers and the arrangement of vascular bundles. In this study, we systematically investigated cell wall- and straw-related traits in a range of wheat germplasm resources and culm mutants using a high-throughput platform for cell wall analysis. We found that varieties with higher breaking force exhibited higher levels of crystalline cellulose but fewer hemicellulose components than other varieties. The lignin content was not consistent with the breaking force; instead, the lignin monomer constitution might be important because a significantly higher proportion of p-hydroxyphenyl (H) and guaiacyl (G) but a lower proportion of syringyl (S) monomers of lignin was found in the higher breaking force group. The crystallinity detected by X-ray diffraction was positively correlated with breaking force, indicating that the physical/chemical properties of polysaccharides also deserve attention. In terms of anatomical characteristics, the varieties with higher breaking force had a lower number and area of smaller vascular bundles in the peripheral sclerenchyma than other varieties. These results, together with the finding of a highly significant correlation between stem breaking force and straw fresh weight, 2nd internode width, flag leaf width and SiO2 content, should provide systematic information for breeding for lodging resistance.

A laboratory evaluation of waterjet cutting of crop residue using the Aqua-Till® liquid coulter

Ultra-high pressure (UHP) waterjet cutting technology is used across a multitude of industries. An agricultural application recently developed by the South Australian No-Till Farmers Association consists of an innovative crop residue cutting ‘liquid coulter’ - known as Aqua-Till®. The wheat straw stem cutting capacity of the device was evaluated under controlled laboratory conditions at the University of South Australia, using a purpose-made straw holding tray moving at a controlled speed under the path of a stationary UHP nozzle. The impacts of technology settings and straw conditions were measured. The cutting performance was assessed based on the degree of fully cut straw stems, integrating the extent of partially cut stems, from a quantity calibrated to an equivalent dry stem load in Mg/ha. Results showed that when operated at 380 MPa pressure, the device delivered very high cutting capacity of wheat straw stems of 10−35 Mg/ha across the range of nozzle orifice diameters (0.15-0.3 mm) and forward speeds (6−12 km/h) tested. The UHP waterjet cutting unit was found to operate most effectively when the residue was wet and placed under compression. Halving travel speed increased the cutting capacity by an average 12 % indicating a non-linear impact of speed. No effect of nozzle to target distance could be detected over the 5−70 mm range tested. The cutting performance of wet, compressed residue was mapped against the water volume rate required over a range of speeds and orifice diameters. Correction factors for extending cutting performance estimations to dry and/or loose residue conditions were also determined. Across the range of nozzle orifice diameters and speeds investigated, the laboratory data for wet compressed residue indicate that a nominal 150 L/ha volume of water, deemed acceptable under Australian dryland cropping conditions, could provide straw stem cutting capacities of up to 12.5 Mg/ha, 19 Mg/ha and 35 Mg/ha at 300 mm, 500 mm and 1000 mm nozzle row spacing, respectively, at a nominal 380 MPa operating pressure. In this study, the waterjet technology demonstrated very effective residue cutting, which could be maximised under specific residue conditions and technology settings. The results indicate that the technology could become an effective tool for assisting residue handling in no-till planting applications, particularly in wet stubble and soft soil environments where traditional mechanical coulters fail. Further research is required to develop accurate operational guidelines for a range of field residue type and conditions, as well as clarify the technology cost-effectiveness in order to facilitate adoption within the no-till cropping industry.

Establishing sex-specific reference interval for the Beckman Coulter UniCel DxI 800 TSH (3rd IS) in Chinese euthyroid population based on a multicenter study

Ultra-high pressure (UHP) waterjet cutting technology is used across a multitude of industries. An agricultural application recently developed by the South Australian No-Till Farmers Association consists of an innovative crop residue cutting ‘liquid coulter’ - known as Aqua-Till®. The wheat straw stem cutting capacity of the device was evaluated under controlled laboratory conditions at the University of South Australia, using a purpose-made straw holding tray moving at a controlled speed under the path of a stationary UHP nozzle. The impacts of technology settings and straw conditions were measured. The cutting performance was assessed based on the degree of fully cut straw stems, integrating the extent of partially cut stems, from a quantity calibrated to an equivalent dry stem load in Mg/ha. Results showed that when operated at 380 MPa pressure, the device delivered very high cutting capacity of wheat straw stems of 10−35 Mg/ha across the range of nozzle orifice diameters (0.15-0.3 mm) and forward speeds (6−12 km/h) tested. The UHP waterjet cutting unit was found to operate most effectively when the residue was wet and placed under compression. Halving travel speed increased the cutting capacity by an average 12 % indicating a non-linear impact of speed. No effect of nozzle to target distance could be detected over the 5−70 mm range tested. The cutting performance of wet, compressed residue was mapped against the water volume rate required over a range of speeds and orifice diameters. Correction factors for extending cutting performance estimations to dry and/or loose residue conditions were also determined. Across the range of nozzle orifice diameters and speeds investigated, the laboratory data for wet compressed residue indicate that a nominal 150 L/ha volume of water, deemed acceptable under Australian dryland cropping conditions, could provide straw stem cutting capacities of up to 12.5 Mg/ha, 19 Mg/ha and 35 Mg/ha at 300 mm, 500 mm and 1000 mm nozzle row spacing, respectively, at a nominal 380 MPa operating pressure. In this study, the waterjet technology demonstrated very effective residue cutting, which could be maximised under specific residue conditions and technology settings. The results indicate that the technology could become an effective tool for assisting residue handling in no-till planting applications, particularly in wet stubble and soft soil environments where traditional mechanical coulters fail. Further research is required to develop accurate operational guidelines for a range of field residue type and conditions, as well as clarify the technology cost-effectiveness in order to facilitate adoption within the no-till cropping industry.

Performance evaluation of the new Beckman Coulter DxH-900 haematology analyzer

Ultra-high pressure (UHP) waterjet cutting technology is used across a multitude of industries. An agricultural application recently developed by the South Australian No-Till Farmers Association consists of an innovative crop residue cutting ‘liquid coulter’ - known as Aqua-Till®. The wheat straw stem cutting capacity of the device was evaluated under controlled laboratory conditions at the University of South Australia, using a purpose-made straw holding tray moving at a controlled speed under the path of a stationary UHP nozzle. The impacts of technology settings and straw conditions were measured. The cutting performance was assessed based on the degree of fully cut straw stems, integrating the extent of partially cut stems, from a quantity calibrated to an equivalent dry stem load in Mg/ha. Results showed that when operated at 380 MPa pressure, the device delivered very high cutting capacity of wheat straw stems of 10−35 Mg/ha across the range of nozzle orifice diameters (0.15-0.3 mm) and forward speeds (6−12 km/h) tested. The UHP waterjet cutting unit was found to operate most effectively when the residue was wet and placed under compression. Halving travel speed increased the cutting capacity by an average 12 % indicating a non-linear impact of speed. No effect of nozzle to target distance could be detected over the 5−70 mm range tested. The cutting performance of wet, compressed residue was mapped against the water volume rate required over a range of speeds and orifice diameters. Correction factors for extending cutting performance estimations to dry and/or loose residue conditions were also determined. Across the range of nozzle orifice diameters and speeds investigated, the laboratory data for wet compressed residue indicate that a nominal 150 L/ha volume of water, deemed acceptable under Australian dryland cropping conditions, could provide straw stem cutting capacities of up to 12.5 Mg/ha, 19 Mg/ha and 35 Mg/ha at 300 mm, 500 mm and 1000 mm nozzle row spacing, respectively, at a nominal 380 MPa operating pressure. In this study, the waterjet technology demonstrated very effective residue cutting, which could be maximised under specific residue conditions and technology settings. The results indicate that the technology could become an effective tool for assisting residue handling in no-till planting applications, particularly in wet stubble and soft soil environments where traditional mechanical coulters fail. Further research is required to develop accurate operational guidelines for a range of field residue type and conditions, as well as clarify the technology cost-effectiveness in order to facilitate adoption within the no-till cropping industry.

Interfacial properties with bonding and failure mechanisms of wheat straw node and internode

The interfacial properties with bonding and failure mechanisms of different anatomical sections of wheat straw stem, namely node and internode, inner and outer surface, with various resins are investigated. An environmentally friendly pre-treatment was employed which led to an improved interface between resins and the micro porous surface of straw. The results showed that chemical functionalities of various surface profiles altered the bonding performance, i.e. extractive, aliphatic fraction of waxes, and silica concentrated on the outer surface, inhibited the bonding quality and the establishment of robust interface. The pre-treatment however, could significantly (P<0.05): (i) modify the surface of straw with the partial removal of extractives, waxes, and silica which made it more hydrophilic and more compatible with water based resins, (ii) cause the microcellular structure of straw to expand and hence inspire the mechanical entanglement on a micro level upon resin solidification and, (iii) increase the tensile strength of node and internode by modifying the cellulose crystallinity. The combined effects of resin, straw and interface led to hierarchical damage process, which could be modelled into four main failure mechanisms representing strong to weak bonding quality.

Comparison of the Structural Characteristics of Cellulolytic Enzyme Lignin Preparations Isolated from Wheat Straw Stem and Leaf

Lignin structure has been considered to be an important factor that significantly influences the biorefinery processes. In this work, the effect of ball milling on the structural components and extractable lignin in enzymatic residues was evaluated, and the structural characteristics of the cellulolytic enzyme lignin preparations isolated from wheat straw stem (SCEL) and leaf (LCEL) were comparatively investigated by a combination of nitrobenzene oxidation (NBO), ozonation, infrared spectroscopy, and 1H–13C heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR). The results showed that 4 h ball-milled samples were good enough for structural analysis with high lignin yield. Both CELs are typical p-hydroxyphenyl-guaiacyl-syringyl lignins which are associated with p-coumarates and ferulates. However, the structure of lignin in wheat straw stem is rather different from that in leaf. Compared to stem lignin, leaf lignin has lower product yields of NBO and ozonation, lower erythro/threo...

Differential behaviour of nodes and internodes of wheat straw with various pre-treatments

This study is aimed at fully understanding wheat straw by investigating important properties for the processing of wheat straw (node and internode) for further production of bio-composites and bio-fuels as they server as great renewable resource. A combination of mild physical treatments and the synergetic effect of each physical treatment were investigated in terms of chemical, surface and mechanical properties. Functional groups changes were monitored in two anatomical sections of wheat straw stem inner and outer surface and the results showed a reduction in the intensities assigned to aliphatic fractions of waxes and silica after each stage of pre-treatments when compared to the untreated samples. The penetration rate (wettability) and hydrophobicity of wheat straw internode outer surface was analysed through contact angle measurements which indicated 35% decrease in hydrophobicity of straw surface therefore increasing the wettability of surface after the combinational pre-treatment. The relationship of surface characteristics to the mechanical properties of wheat straw was also investigated by testing the single strand tensile strength of nodes and internodes before and after pre-treatments. Mechanical test revealed 35% increase in tensile strength of wheat straw after the pre-treatment in comparison to untreated wheat straw. The thermogravimetric analysis clearly illustrate that the thermal stability of the wheat straw increased after the pre-treatment which is encouraging for the bio-composite application.

Revealing the morphology and chemical distribution of nodes in wheat straw

Morphology and chemical distribution of wheat straw stem, including nodes and internodes, were profiled and thoroughly analysed through a combination of qualitative and quantitative analytical techniques. It was found that the morphology across node area has great variety when the longitudinal profile was investigated in the upwards direction to the grain head; the node core morphology revealed a very dense zone with elliptical shaped rings organised in order to provide the mechanical strength to the overall stem. ATR-FTIR results for the chemical functional groups of outer and inner surfaces of node and internode also showed differences in terms of concentration of functional groups present in each section. It was revealed that the outer surface of wheat straw stem has a higher concentration of aliphatic fraction of waxes compared to the inner surface, with the highest being in the node area. EDX-SEM results were averaged for node and internode and also for inner and outer surfaces for quantitative comparison. It was found that the outer surface of wheat straw had considerable higher Si contents than the inner surface. Also higher content of C in the node outer surface is an indication of high quantity of wax which is in agreement with ATR-FTIR results. The crystallinity of node and internode was investigated using XRD; it was found that node is more amorphous than internode with the crystallinity index of 34.73% compared to 45.00% of internode. The profile of wheat straw morphology in the nodes has never been reported; the results of the quantitative and qualitative structural analysis through in-depth microstructure interpretation, and detailed and accurate chemical composition improved the understanding of straw biomass.

Exogenous fibrolytic enzymes to unlock nutrients: Histological investigation of its effects on fibre degradation in ruminants

There is a need for a better understanding of the mode-of-action of exogenous fibrolytic enzymes (EFE) used as additives in ruminant feeds. Four forages, treated with EFE, were evaluated in vitro and histologically, in an attempt to determine the effect of EFE on tissue degradation. Weeping love grass, kikuyu leaf material, lucerne and wheat straw stem material were histologically evaluated. Simultaneously, milled samples were incubated in the rumen fluid inoculated media for the determination of in vitro digestibility. The main focus, however, was a quantitative assessment of the degradation of the plant tissue at histological level over a 24 h incubation period. Degradation of cell wall components were quantified using the image analysis software. After 12 h of incubation, cell walls of the metaxylem of kikuyu and weeping love grass leaf material were thinner for the EFE treatment than for the control treatment. Treatment also resulted in a significant thinning effect of the cell walls of kikuyu phloem (12 h) and the adaxial epidermis (24 h). The abaxial epidermis at 12 h was thinner for weeping love grass due to EFE treatment. For stem material, a thinning of the epidermis of EFE treated lucerne was observed. Histological findings were concomitant with higher in vitro digestibilities of EFE treated lucerne and kikuyu. It was concluded that image analysis can be useful to quantify changes in cell wall due to the treatment of forages with EFE. There was a definite, subtle thinning effect of EFE on cell wall thickness of plant material which could be indicative of the mode-of-action of EFE.

Comparison of sodium carbonate pretreatment for enzymatic hydrolysis of wheat straw stem and leaf to produce fermentable sugars

The specific characteristics of biomass structure and chemical composition of straw stem and leaf may result in different behavior of pretreatment and enzymatic hydrolysis. In this work, sodium carbonate (SC) was employed as a pretreatment to improve the enzymatic digestibility of wheat straw. The chemical composition and enzymatic hydrolysis of wheat straw stem and leaf (sheath included) were investigated comparatively. Most of the polysaccharides are kept in the solid fractions after SC pretreatment, while the stem has better delignification selectivity than leaf at high temperature. The enzymatic hydrolysis efficiency of wheat straw leaf is significantly higher than that of stem. The maximum total sugar yield from SC pretreated leaf was about 16% higher than stem. The results show that sodium carbonate is of great potential to be used as a pretreatment for the production of bioethanol from straw handling waste in a straw pulp mill with a low feedstock cost.

Cell Wall Esterified Phenolic Dimers: Identification and Quantification by Reverse Phase High Performance Liquid Chromatography and Diode Array Detection

An optimized high performance liquid chromatography (HPLC) procedure has been developed for the analysis and quantification of all of the known ferulic acid dehydrodimers, and the principle phenolic aldehydes and acids, found in the cell walls of higher plants. The HPLC system uses an ODS2 reverse phase column (5 μm particle size) eluted with a methanol, acetonitrile and water gradient with detection at 280 nm. In addition to providing baseline resolution of most components, the method employs a spectrometric detector which enables the precise identification of eluted components through the analysis of their spectral properties. Analysis of the cell wall phenolics of wheat straw stem (Triticum vulgare) was carried out using this method which is highly versatile and, for certain components, more sensitive than the current gas chromatography–mass spectrometry methodology.

Ruminal digestion and glycosyl linkage patterns of cell wall components from leaf and stem fractions of alfalfa, orchardgrass, and wheat straw

Samples of alfalfa, orchardgrass, and wheat straw were hand-separated into leaf and stem fractions that were subjected to in situ ruminal fermentation for various lengths of time to assess the rate and extent of degradation of cell wall neutral monosaccharides, uronic acids, acetyl groups, and hydroxycinnamic acids. A second objective was to measure the glycosyl linkage patterns of leaf and stem fractions of substrates before and after ruminal fermentation. Samples were fermented for 0, 6, 12, 24, 48, 96, and 192 h in each of two ruminally cannulated steers. In situ disappearance data were fitted to a first-order exponential equation to estimate the following substrate parameters: insoluble, potentially digestible fraction (fd), indigestible fraction (fi), and fractional rate constant of degradation of the potentially digestible fraction (k). Leaves contained larger concentrations of crude protein and smaller concentrations of cell wall components than did stem fractions. Estimates of fi were 7.3, 39.2, 22.1, 49.3, 27.7, and 36.3 for dry matter disappearances for alfalfa leaf, alfalfa stem, orchardgrass leaf, orchardgrass stem, wheat straw leaf, and wheat straw stem, respectively. Averaged across substrates, estimates of fi for arabinose, galactose, glucose, xylose, uronic acids, acetyl groups, and p-coumaric acid were 16.5, 11.4, 14.8, 31.2, 12.8, 25.3, and 22.6% in leaf fractions and 29.5, 19.9, 37.5, 56.2, 35.0, 52.4, and 44.6% in stem fractions. Rates of digestion of all monomeric components except galactose and xylose were greater (P < .05) for alfalfa than for orchardgrass or wheat straw. Differences in digestibility of cell wall components from leaf and stem fractions were greater in alfalfa and orchardgrass than in wheat straw. Glycosyl linkage analysis indicated that xylans in leaf and stem fractions of alfalfa, orchardgrass leaf, and wheat straw stem that resisted degradation had a lower degree of substitution with acid-labile constituents (i.e., other monosaccharides) than was found in original substrates. Different rates and extents of digestion of leaf and stem fractions of forages explain part, but not all, of the observed differences in digestibilities of cell wall monomers by ruminants.