Straw Stem Research Articles

The Residue Chemistry Transformation Linked to the Fungi Keystone Taxa during Different Residue Tissues Incorporation into Mollisols in Northeast China

Managing carbon input from crop straw in cropland ecosystems could increase soil organic carbon (SOC) sequestration to achieve C neutrality and mitigate climate change. The complexity of the chemical structures of crop residue largely affects SOC sequestration. Fungi communities play an important role in the degradation of crop residues. However, the relationship between the fungal community composition and the chemical structures of crop residues remains unclear and requires further investigation. Therefore, a 120-day incubation experiment was conducted in Mollisols in Northeast China to investigate the decomposition processes and dynamics of maize straw stem (ST), leaf (LE) and sheath (SH) residues using 13C-NMR spectroscopy. Additionally, the microbiomes associated with these residues were analyzed through high-throughput sequencing to explore their relationship. Our results showed that the alkyl C contents in all treatments exhibited increases ranging from 15.1% to 49.1%, while the O-alkyl C contents decreased, ranging from 0.02% to 11.2%, with the incubation time. The A/OA ratios of ST, LE and SH treatments were increased by 23.7%, 43.4% and 49.3% with incubation time, respectively. During the early stages of straw decomposition, Ascomycota dominated, and in the later stage, Basidiomycota were predominant. The class of Sordariomycetes played a key role in the chemistry transformation of straw tissues during decomposition. The keystone taxa abundances, Fusarium_kyushuense, and Striatibotrys_eucylindrospora, showed strong negative correlations with di-O-alkyl C and carbonyl-C content and positive correlations with the β-glucosidase and peroxidase enzyme activity, respectively. In conclusion, our study demonstrated that the keystone taxa play a significant role in regulating the chemical structures of straw tissues, providing a better understanding of the influence of residue quality on SOC sequestration.

Ephedrae Herba: A Review of Its Phytochemistry, Pharmacology, Clinical Application, and Alkaloid Toxicity.

Ephedrae Herba (Ephedra), known as "MaHuang" in China, is the dried straw stem that is associated with the lung and urinary bladder meridians. At present, more than 60 species of Ephedra plants have been identified, which contain more than 100 compounds, including alkaloids, flavonoids, tannins, sugars, and organic phenolic acids. This herb has long been used to treat asthma, liver disease, skin disease, and other diseases, and has shown unique efficacy in the treatment of COVID-19 infection. Because alkaloids are the main components causing toxicity, the safety of Ephedra must be considered. However, the nonalkaloid components of Ephedra can be effectively used to replace ephedrine extracts to treat some diseases, and reasonable use can ensure the safety of Ephedra. We reviewed the phytochemistry, pharmacology, clinical application, and alkaloid toxicity of Ephedra, and describe prospects for its future development to facilitate the development of Ephedra.

Effect of calcination temperature on the pozzolanic activity of maize straw stem ash treated with portlandite solution

Effect of calcination temperature on the pozzolanic activity of maize straw stem ash treated with portlandite solution

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.

Analysis of Effect of Cooking Liquor of Paper Mulberry Fiber on Physical Properties of Fiber and Paper

This study was investigated the physicochemical properties of cooking agent used as raw materials of Hanji (traditional Korea paper). The ashes have been prepared by incomplete burning of five kinds of agricultural by-products (pepper stem, beanstalk, straw stem, sesame stem and buckwheat stem) from S company in Chungcheong-do. Then, various analyses were conducted in this study, including the main ingredients of ash and lye, yield and alkalinity to better understand the characteristics of the lye. As a result, the lye was manufactured under the same conditions, the cooking efficiency of the paper mulberry bast fiber by pepper stalk, soybean stalk and sesame stalk was higher than that of straw stalk, buckwheat stalk. In addition, the viscosity and lignin content were analyzed to investigate the properties of paper mulberry bast fiber after cooking process. Similarly the conditions of brightness, formation and folding endurance of the handmade paper-sheet were measured in order to compare and analyze the characteristics of the handmade paper-sheet after lye into the cooking by condition. As a result, the brightness of handmade paper-sheet was high and the formation was also the fibers are evenly distributed after cooking with pepper stem, beanstalk and sesame stem.

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.

On-Farm Diversity Assessment and Participatory Varietal Evaluation of Cold-Tolerant Rice in Mid-Hills of Nepal

Drawing upon consequentially growing food insecurity in mid-hills attributed to poor adoption levels inter alia inflicted by narrow range of locally adaptive farmer’s preferred cold tolerant rice varietal options in national agricultural system, the present study was undertaken. We conducted on farm diversity assessment of 60 high altitude rice genotypes from ex-situ and on farm employing un-replicated diversity block in 2015. Subsequently, we identified eight promising locally adaptive genotypes as candidate genotypes based on the inferences of diversity block trial and evaluated them through participatory variety selection (PVS) using randomized block design in 2016 under on-farm conditions. Our studies revealed marked diversity among the Nepalese cold-tolerant rice genotypes. The UPGMA cluster analysis categorized the 60 genotypes into six distinct clusters. Strong positive correlation between grain yield and plant height; panicle length; straw yield and strong negative correlation between grain yield and 1000-grain weight was detected. PCA suggested traits viz., plant height, panicle length, days to 50% heading, and grain yield to be principal discriminatory characteristics of the cold-tolerant rice. Seto Kattike, Naulo Dhan, and Borang were most promising and adaptive genotypes whose eminence were justifiably corroborated and validated by farmer’s overall evaluation. The most valued farmer’s selection criteria were grain and straw yield, earliness, disease resistance, and stem borer tolerance. The findings bolster employment of novel and proven participatory plant breeding approach using diversity kits and IRD kits to expand and promote varietal choice options for immediate benefits to the farmers and facilitate rapid varietal release and registration.

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.

Study of Sound Absorption Coefficients and Characterization of Rice Straw Stem Fibers Reinforced Polypropylene Composites

In this study, both untreated rice straw stem fibers and fibers treated with sodium hydroxide were used. Maleic anhydride polypropylene (MAPP) was used to enhance adhesion of the fiber with the matrix. Composites were prepared with various combinations of fiber, ranging from 10 wt.% to 25 wt.%, and polypropylene in addition to 2 wt.% MAPP. These composites were then tested for acoustical, mechanical, thermal, infrared spectral, and morphological properties. The fibers were treated by being soaked in 5 wt.% NaOH solution at 30 C for 30 min. The composites with treated fiber exhibited higher thermal stability, tensile strength, sound absorption, and fiber-matrix adhesion than the composites with untreated fiber. The results of sound absorption measurements showed that the composites with higher fiber content had better sound absorption than the composites with lower fiber content. The changes in the peaks in the Fourier transform infrared spectrum indicate that the alkaline treatment removed hemicellulose and lignin from the rice straw stem fibers.

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.

Assessing of soil aggregate stability: the sand-correction and its relevance

Soil structure and changes in its quality caused by Maize stem (1), Wheat straw (2) and Maize stem &amp; wheat straw (3) addition were assessed by three aggregate-stability indices. We observed that the NSI index formula proposed by Six et al. (2000) was nonsensitive to the changes in soil structure caused by the investigated organic matter addition. Furthermore it overestimates the aggregate-stability of the investigated silty sandy loam soil. Therefore we proposed a new modified NSI formula which is sensitive to the questionable treatments and that resulted in a morerealistic NSI data. The most sensitive index to differences of the investigated treatments were the Mean weight diameter (MWD) proposed by van Bavel (1953, in Kemper és Rosneau, 1986).

Isolation and characterization of rice straw degrading Streptomyces griseorubens C-5

To reutilize rice straw generated during the agricultural production process, the actinomycete strain C-5 was isolated from soil that was under the stook for several years in the Heilongjiang province of China by using multiple selective culture media. Strain C-5 was identified as Streptomyces griseorubens by China General Microbiological Culture Collection Center (CGMCC) through morphological and physiological characterization combined with the result of 16S rRNA gene sequence and data analysis. This strain has simultaneous cellulase, laccase, peroxidase, xylanase and pectinase activity. The various chemical composition of rice straw were determined during fermentation process. Simultaneously the biodegradation process of rice straw stem was observed by scanning electron microscope (SEM). It is predicted that strain C-5 could decompose rice straw effectively and had promising prospects of being applied in improving the resource utilization of rice straw.

Water‐Stable Aggregation in Relation to the Normalized Stability Index

In spite of the good quality of soils in Hungary, soil structure is deteriorated by intensive tillage. Because of general dissimilarities between field and laboratory circumstances and therefore lack of comparability, the former results are questionable. An optimized method initiated by Six, Elliott, and Paustian (2000) was adapted to investigate changes in soil structure and quality caused by different kinds of added organic matters. Our samples originated from the long‐term fertilization experiments in Keszthely, western Hungary. The experiments were set up in 1960. The texture of the investigated soil is sandy loam; the type of soil is Eutric Cambisol (soil type FAO) or Alfisol (soil type USDA). Tillage and its depth was fall plowing to 25 cm. Crop rotation was maize–maize–potato–winter wheat–winter wheat. Samples were taken from depths of 0–20 and 20–30 cm, from the fallow, which had the same treatment as the potato field. Changes in soil structure were quantified by wet sieving. Soil structural stability was characterized by comparing aggregate size distribution after the use of a lower and a higher disruptive force, which was simulated by two different pretreatments. Determinations were done in triplicates. Soil structure may be improved by adding readily decomposable organic matter. The extent of amelioration depends on the chemical buildup and decomposability of the crop residues. Three different kinds of organic matters were investigated: (1) maize stem (M), (2) wheat straw (W), and (3) maize stem and wheat straw (MW). By comparing the aggregate stabilizing effects of the differently decomposable organic matters to each other and predicting the lower decomposability but persisting effect of M, the expected MW > M > W order was proven. These are parallel with those results of Harris, Chesters, and Allen (1966) and John et al. (2005), who observed decreasing aggregate stability in the M > W order. We observed increased macroaggregate stability in both macroaggregate fractions (2000–7000 µm and 250–2000 µm) in all three case of organic‐matter addition, but these newly formed bindings were easily broken up because of the weaker bindings of the higher aggregate hierarchical orders. This is remarkable mainly in the upper layer because crop residues were mixed to the upper layer and therefore could not have affected the lower one. Furthermore, adding organic materials has decreased the mass of the 53–250 µm microaggregate fraction in all treatments and depth layers and in addition in both pretretments. This proves that adding organic matter enhances the transient and temporary binding agents between microaggretages grouped into macroaggregates but that these bindings are temporal.