Amount Of Straw Research Articles

Effects of Different Straw Incorporation Amounts on Soil Organic Carbon, Microbial Biomass, and Enzyme Activities in Dry-Crop Farmland

The direct input of straw to the field can increase the source and supply of soil carbon and nitrogen, change the soil microbial biomass and enzyme activity, and affect the soil organic carbon sequestration, which in turn affects soil fertility and quality. In this study, a three-year field orientation experiment was conducted to investigate the effects of straw input on soil microbial biomass, enzyme activity, and soil organic carbon at different straw incorporation amounts (0, 3000, 7000, and 14,000 kg/hm2). The results showed that soil microbial biomass, enzyme activity, and organic carbon content increased with the increase in straw amount, and the increase in 4-fold straw input (T4) treatment was significantly larger than that of other treatments; the microbial biomass, enzyme activity, and SOC (soil organic carbon) in different soil layers were 0–10 cm > 10–20 cm > 20–30 cm; and straw incorporation amounts had a significant effect on soil microbial biomass, enzyme activity, and SOC. The amount of straw input to the field had a highly significant positive effect on soil microbial carbon and nitrogen and SOC (p < 0.001). In conclusion, four times the amount of straw input to the field had the most obvious effect on enhancing soil organic carbon content, microbial biomass, and enzyme activity. This has important implications for the development of sustainable agriculture.

Analysis of the fluorescence spectral characteristics of dissolved organic matter in a black soil with different straw return amounts

Straw return improves soil carbon pool and dissolved organic matter (DOM) characteristics in black soil. Optimal straw return rate is the key to promoting straw return practices in farmland in Northeast China. The experiment was conducted at the Science and Technology Park of China Grain Storage and Northern Corporation in NenJiang, Heilongjiang Province, straw return at 0 kg hm−2, 3000 kg hm−2, 4500 kg hm−2, and 9000 kg hm−2. In the seventh year of the experiment, we used three-dimensional excitation-emission matrices combined with Parallel Factor analysis to characterize the fluorescence characteristics of DOM of black soils. The results showed substantial improvement in soil physical characteristics and soil organic matter (SOM) following straw return, SOM content rises in proportion to the amount of straw returned, and a significant positive correlation coefficient between water-holding capacity (WHC) (p < 0.001, r = 0.82) and dissolved organic matter (DOC) (p < 0.01, r = 0.77). Moreover, straw return significantly increased the richness of three fluorescent components, namely fulvic acid (UV and visible fulvic acids), humic-like acid, and protein-like (short and long-wavelength tryptophan). The fluorescence intensities of these components were lower in straw treatments than in no straw return. The fluorescence intensities of fulvic and humic acids showed decreasing and increasing trends, respectively, with increasing straw return amount. The fluorescence spectroscopy data of DOC demonstrated the key role of high straw return amounts in enhancing substantially the metabolic activity of soil microorganisms. Overall, straw-returning practices improve soil fertility and can be beneficial for black soil farmlands, with the optimal return rate observed at 4500 kg hm−2.

Construction and validation of a mathematical model for the pressure subsidence of mixed crop straw in Shajiang black soil

The soil properties of mixed crop straw do not enable conventional pressure subsidence models to characterize the relationship between straw amount and pressure-bearing properties accurately. Based on the distribution of straw in the field, this study explored the effect of the amount of surface straw cover on the pressure subsidence relationship in Shajiang black soil. The quadratic rotated orthogonal combination test was used to quantify the mathematical relationships of Shajiang black soil pressure subsidence modeling with the amount of surface straw cover (SSC) and mass mixing ratio of soil to straw (MSS). Then, using the weighted least squares method, the pressure subsidence parameters (cohesive deformation modulus, friction deformation modulus, and subsidence index) were obtained, and the Bekker model was modified to construct a pressure subsidence model for the straw-containing soil. Finally, the modified model was verified under conditions of a water content of 18 %, the SSC of 2.5 t·ha−1, and the MSS of 2.5 %. Results showed that the proposed pressure subsidence model predicted the value with a relative error of 2.21 % compared with the experimental measurements. The model’s predicted value accuracy improved by 10.65 % compared to the conventional model. From these results, this study proposes that a mixed crop straw Shajiang black soil pressure subsidence model can predict the soil’s internal stress transfer and stress–strain conditions.

Effects of Nutrient Deficiency on Crop Yield and Soil Nutrients Under Winter Wheat–Summer Maize Rotation System in the North China Plain

The wheat–maize rotation system in the North China Plain (NCP) has a large amount of crop straw. However, improper crop straw management and blind fertilization lead to nutrient imbalance and accelerated nutrient loss from the soil, ultimately leading to nutrient deficiency affecting the wheat–maize rotation system. In order to explore the effects of nutrient deficiency on the yield and nutrient use efficiency of wheat and maize, the experiment was conducted in a randomized complete block design consisting of five treatments with three replicates for each treatment: (1) a potassium fertilizer deficiency and appropriate nitrogen and phosphate fertilizer treatment (NP); (2) a phosphate fertilizer deficiency and appropriate nitrogen and potassium fertilizer treatment (NK); (3) a nitrogen fertilizer deficiency and appropriate phosphate and potassium fertilizer treatment (PK); (4) an adequate nitrogen, phosphorus, and potassium fertilizer treatment (NPK); and (5) a no-fertilizer treatment (CK). The results showed that, compared with CK, the yields of wheat and maize treated with NPK were increased by 21.5% and 27.5%, respectively, and the accumulation of the dry matter of the wheat and maize was increased by 42.5% and 57.3%. In all the deficiency treatments, the NK treatment performed better in terms of yield compared to the NP and PK treatments, while the NP treatment demonstrated a greater increase in dry matter accumulation. The NPK treatment significantly improved the nitrogen use efficiency (NUE) and nitrogen harvest index (NHI) of the wheat and maize, which resulted in higher nitrogen accumulation in the NPK treatment, and the NP treatment was the best among the other nutrient deficiency treatments. The inorganic nitrogen content showed a similar trend. In conclusion, nutrient deficiency can severely restrict crop growth. Nitrogen deficiency can significantly reduce crop yields. Phosphorus deficiency had a greater impact than potassium deficiency in terms of nutrient absorption and accumulation. Therefore, nitrogen fertilizer application should be emphasized in crop rotation systems, with moderate increases in phosphorus fertilizer application. This practice can effectively improve the nutrient deficiency under the wheat and maize rotation system in the NCP and complete a rational fertilization system.

Effect of postharvest sugarcane straw amount and herbicides on Digitaria spp. control and green cane yield

Abstract New agronomic practices are emerging in the green cane system to utilize sugarcane (Saccharum officinarum L.) straw for energy cogeneration, which necessitates its removal from the soil surface. This study has three main objectives: (1) evaluate the population dynamics and composition of Jamaican crabgrass (Digitaria horizontalis Willd.) and large crabgrass [Digitaria sanguinalis (L.) Scop.] under different sugarcane straw amounts, with and without herbicide treatment; (2) assess the development of sugarcane under different straw amounts; and (3) determine the amount of sugarcane straw that should be kept on the soil surface after harvest to ensure that it does not compromise the chemical control for Digitaria spp. in ratoon cane in a green cane system. We conducted this research at two experimental sites, one at the beginning and the other during the middle of the harvest season, over a span of 2 yr. Our primary treatments consisted of different amounts of sugarcane straw after harvest on the soil surface (0, 5, 10, and 15 Mg ha−1), while secondary treatments included the herbicide application (sulfentrazone + tebuthiuron for the beginning of harvest season and isoxaflutole + tebuthiuron for the middle of harvest season). The Digitaria spp. exhibited higher density (four times more) and dry matter (two times more) in scenarios with a lower sugarcane straw amount (5 Mg ha−1) on the soil surface and no herbicide application. However, a higher straw amount (15 Mg ha−1) contributed to reduced Digitaria spp. infestation and to improved sugarcane yield. According to this research, it is essential to maintain at least 10 Mg ha−1 of sugarcane straw on the soil surface and remove only 5 Mg ha−1 for energy cogeneration.

Nutrient circularity of an anaerobic digestion project in a typical intensive rice cultivation village in the Vietnamese Mekong delta region: a regional material flow analysis and discussion of modeling practices

AbstractRice is the third largest agricultural commodity in the world. Intensive rice production is associated with high fertilizer application, and vast quantities of rice straw are often disposed of by open burning. As emissions of N and P from fertilizer and their impacts are highly spatially disparate, it is crucial to locally assess potential solutions for nutrient circularity. A model framework was established to evaluate the potential impact of local N, P and C cycles along with suitable circularity indicators. This framework was applied for a case study in the typical intensive rice cultivation village Hậu Mỹ Bắc B in the Mekong Delta using STAN modeling software. A novel technique, based on a patented temperature-phased anaerobic digestion (TPAD) loop-reactor design was investigated as a measure to reduce rice straw open burning, generate bioenergy and recover digestate for nutrient recirculation. The case study showed that rice straw TPAD could reduce open burning by 60%, while the N recovery rate increased to 21% when 200 ± 34 Mg/a of inorganic fertilizer was replaced with digestate. For C and P, the recovery rates increased to 14% and 11%, respectively. Based on the results, we concluded that TPAD has a strong impact on local nutrient circularity in terms of recirculation and sufficiency. Furthermore, the developed framework is suitable to use for master planning of nutrient circularity and for technological impact assessments at local scale. However, versatile, dynamic, and comparable monitoring frameworks with harmonized indicators to identify options for nutrient circularity are required for the detailed modeling of regional nutrient management.

Enhancement of soil humic acid hydrophobicity by 5 consecutive years of full-amount straw shallow-mixed field return

Crop yield is directly influenced by the storage and stabilisation of soil organic carbon (SOC), which is determined by the hydrophobicity of soil humic acid (HA). Changes in soil HA hydrophobicity, humic substances, SOC and crop yield were compared after the application of different amounts of straw returns in the field, and the contribution of straw application in enhancing HA hydrophobicity was examined. The treatments included no straw application and soil stirring, no straw application with soil stirring, application of half-amount straw shallow-mixed field return, application of full-amount straw shallow-mixed field return and application of double-amount straw shallow-mixed field return. Using elemental analysis, infrared spectroscopy and fluorescence spectroscopy, the structural hydrophobicity of soil HA was exhaustively characterised. The results showed that the hydrogen to carbon ratio of HA increased by 11.46 %, the ratio of hydrophobic to hydrophilic intensity increased by 21.02 %, and the ratio of peak B to peak A fluorescence intensity decreased by 32.21 % after 5 years of full amount straw shallow-mixing field return compared to no straw application and soil stirring. The observed results indicate that the augmentation in hydrophobicity stimulates the formation of HA, enhances soil humification, elevates SOC content by 9.78 % and potentially contributes to the ultimate crop yield increase by 22.98 %. Compared with stirring the soil, the contribution rate of applying full amount of straw to increase HA hydrophobicity was 49.57–62.05 %, and the contribution rate to increase SOC and yield were 54.59 % and 76.37 %, respectively. While stirring the soil contributed to increasing hydrophobicity, straw application persisted as the primary factor in enhancing hydrophobicity. The findings of this study have significant implications for understanding the mechanism by which straw improves HA hydrophobicity, thereby facilitating carbon sequestration and increasing crop yield.

Dicamba: Dynamics in Straw (Maize) and Weed Control Effectiveness

Dicamba is a post-herbicide, showing some activity in soil, and its dynamics can be influenced by several factors, including the presence of straw. Brazil has more than 50% of its production area in a no-till system; thus, a good amount of the herbicide is intercepted by the straw. This study aimed to evaluate dicamba dynamics in straw and weed control efficacy when sprayed as a PRE herbicide. For this, five different studies were conducted: we utilized different straw amounts (1) and different drought periods (2) for straw sprayed with dicamba and dicamba + glyphosate to evaluate its release from straw, different straw amounts (3), different drought periods (4), and wet and dry straw (5) to evaluate pre-emergence weed control (Bidens pilosa and Ipomoea grandifolia) and dicamba availability in medium-texture soil. Around 80% of dicamba was released from the straw after 100 mm of rainfall. One day after dicamba application, 65–70% of dicamba was released from the straw with 20 mm of rainfall, while for 7 and 14 DAA, 60% was released. Dicamba was efficient in controlling the pre-emergence of both species studied, and the amount of straw did not interfere in weed control; however, dicamba was less available in the soil after rainfall when sprayed in the straw than when sprayed directly in the soil. Up to 80% of dicamba can be released from the straw after 100 mm of rainfall and weed control was efficient for the species studied; however, the carryover effect in sensitive crops might become an issue.

Does higher ratio of wheat straw addition decrease PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice?

There are considerable studies focusing on impacts of straw returning on PAHs degradation and bioavailability in PAHs-contaminated upland soils, while similar research in paddy soils is limited. Incubation experiments and pot trials were conducted to study effects of straw returning on PAHs degradation in paddy soils and PAHs accumulation in rice, respectively. There are threshold effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils. The inflection point of PAHs degrading was recorded under 0.8 % wheat straw treatment (conventional (CS) and pretreated wheat straw (PS)), which increased PAHs degradation by 18.13–32.36 %. The lowest PAHs concentrations in rice were recorded under 1 % straw (CS and PS) treatment, which was attributed to the highest PAHs degradation in rhizosphere soils. Compared to CS treatment, PS treatment significantly (p < 0.05) increased PAHs degradation by 7.93–10.28 % and PAHs concentrations in rice by 12.38–45.87 % due to that increasing dissolved organic carbon (DOC) enhanced PAHs concentrations in porewater of rhizosphere soils. Higher diversity enhanced the metabolic pathways and function genes to degrade PAHs by improving bacterial phenotypes and biochemical processes under 1 % wheat straw and PS treatment. The present study firstly demonstrated that the effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice depended on amount and methods of straw returning.

How do different amounts of straw as well as compost in the home pen affect the rooting motivation of growing-finishing pigs?

Rooting is a strongly motivated, species-specific behaviour of pigs. Most housing systems do not provide appropriate materials that enable the full expression of this behaviour, and it remains unclear whether straw is suitable to entirely fulfil the rooting motivation of pigs. We therefore investigated the suitability of small (minimal) and large (deep) amounts of straw as well as large amounts of compost to satisfy rooting motivation in pigs. Fifty-seven growing-finishing pigs were housed in three pens, each providing permanent access to one of the three treatment substrates. Eight pigs per group were tested individually in a classical preference test (PT) and another eight pigs in a conditioned place preference test (CPPT). In the tests, pigs could show their preference to consume freely available feed (“feed”) or feed hidden in sawdust (“root”). In the CPPT, feed was only present during training but not during testing. Pigs were exposed to the test situation twice, with approximately 72 kg and 115 kg BW. In both tests, the following variables were measured and used as outcome variables in linear mixed effect models: first decision to choose one of the two stimuli (“feed” or “root”), duration of time spent in proximity to “root”, number of changes between stimuli, and latency to the first decision. Overall, the pigs’ first decision (by tendency; P = 0.076) and the duration in proximity to “root” (P = 0.034) varied among treatments: Pigs housed with minimal straw tended to be more likely to choose “root” first (posthoc comparison; P = 0.090) and spent more time in proximity to “root” (P = 0.030) than pigs housed with compost, whereas pigs housed with deep straw were intermediate. Interestingly, the patterns of response to the treatment differed depending on the behavioural tests for both, first decision (interaction; P = 0.032) and duration in proximity to “root” (interaction; by tendency; P = 0.006). In addition, pigs in the PT changed more often between stimuli than pigs in the CPPT (P < 0.001). There was a tendency for an interactive effect between test and treatment for latency to first decision (interaction; P = 0.082), though pairwise comparisons did not reveal any differences. We concluded that in this study housing with permanent access to compost satisfied rooting motivation in pigs more than housing with minimal amounts of straw.

Effect of Variety on Nutrient Intake and Nutrient Removal by Cereals

The results of field experiments are presented, in which the influence of varietal characteristics of grain crops of different breeding periods on the effectiveness of using mineral fertilizers for them on various soils was studied. Special attention was paid to the specific removal of nutrients, which means the consumption of nitrogen, phosphorus and potassium of 1 ton of grain harvest with an appropriate amount of straw. The results of the experiments showed that the studied varieties responded differently to the application of fertilizers. Almost all modern varieties provided higher yields compared to previously zoned ones. The Mironovskaya 808 winter wheat variety on sod-podzolic soil was almost 2 times inferior to the Moskovskaya 39 variety and 1.7 times inferior to the Lgovskaya 4 variety on leached chernozems when applying the same dose of NPK. Similar data were also obtained for spring barley of the Moskovsky 121 variety and NUR and Elf varieties on sod-podzolic soils, where when N60P60K60 was applied, a yield of 2.7 t/ha was obtained in the first case and 4.9 and 4.7 in the second. Identical results were also observed on leached chernozems and light chestnut soils. In experiments with spring wheat, the result was the same, but the yield of this crop was lower compared to winter wheat and spring barley. The varieties of the studied cereals reacted to a lesser extent to changes in the specific removal of nutrients, and the data obtained did not show a sufficiently clear pattern, which necessitates continued research in this direction.

Assessing and enhancing sustainable rice straw management for environmental conservation in Yen Thanh District, Nghe An Province, Vietnam

This study assessed the current management of rice straw in Yen Thanh District, Nghe An Province, and propose solutions for sustainable agricultural development. A survey was conducted with 120 households in four communes to determine straw use and management practices. The findings revealed six common methods of using and managing rice straw in Yen Thanh District: open burning, burying, mushroom plantation, using it for husbandry feeding, selling, and giving it to others. These practices vary based on the crop season. Open burning is the most prevalent practice, accounting for 98.15% and 89.52% during the winter-spring and summer-autumn harvests, respectively. A crucial step in establishing a pollution control and management database is a comprehensive inventory of emissions. Consequently, authorities and environmental scientists are currently focusing on the emission inventory, particularly emissions resulting from open-burning rice straws. The estimated total amount of rice straw produced annually is 159,732 tons, with 151,384 tons being directly burned in the fields. This burning releases significant emissions, including 1,005.18 tons of PM2.5, 1,102.08 tons of PM10, 21.80 tons of SO2, 142,543.18 tons of CO2, and more, negatively impacting the environment, human health, and agriculture. Additionally, it was observed that most farmers are inclined to continue burning rice straw out of habit in the upcoming years. The study suggests promoting alternative straw management practices such as mushroom cultivation, biochar production, and organic fertilizer production to reduce burning and its associated negative consequences. This information would be invaluable for managers to effectively plan for the future management of rice straw

Agricultural Tire Test: Straw Cover Effect on Reducing Soil Compaction by Cargo Vehicles

Agricultural cargo vehicles are responsible for applying severe soil pressures. However, the ground straw cover can attenuate the loads applied by wheels to the soil surface. This research evaluated the effect of three tires, p1—Radial Very Flex, p2—Radial Improved Flex, and a p3—Bias Ply tire, on three amounts of straw on the soil surface (0, 15, and 30 Mg ha−1). We adopted a completely randomized design (CRD) with a rigid surface for three replications for the total contact area and punctual area claws. The soil bin test verified the deformable surface, tread marks, and soil penetration resistance (SPR). The tire’s claw design determines its punctual contact area, and the construction model determines the total contact area. The contact area in the soil bin increased linearly due to a increase in straw covering, reducing sinkage; p2 to 30 Mg ha−1 straw shows the most significant contact area, p1 and p3 showed no difference. A straw increase from 0 to 30 Mg ha−1 increased the contact areas by 25.5, 38.0, and 20.0% for p1, p2, and p3, respectively. Compared to the rigid surface, the p1 and p3 contact areas in the soil bin increased 6.2, 6.8, and 7.8 times in bare soil, 15, and 30 Mg ha−1; for p2, this increase was up to 4.2, 4.5, and 5.9 times on the same surfaces. Keeping the straw on the soil improves its physical quality by reducing the SPR, so the straw has a buffer function in the wheel–soil relationship.

Remote Sensing Inversion of Soil Organic Matter Content in Straw-Returned Fields in China’s Black Soil Region

China’s black earth region is the country’s corn golden belt, and returning corn straw to the field not only helps improve the Soil Organic Matter (SOM) content and soil fertility, but also resolves environmental pollution caused by straw burning. To study the effects of different years and amounts of straw returned to the field on SOM content, this study used soil sampling data from a conservation tillage experimental base in Gaojia Village, Lishu County, combined with indoor measurements of imaging spectral data, to establish a prediction model of SOM content by applying partial least squares regression, and inverting the SOM content in the study area. The results showed that the PLSR model accuracy using indoor measured soil imaging spectral data as the independent variable was high. The accuracy coefficients of samples with different field return and different field return amounts, R2, were 0.9176 and 0.8901, respectively, which better predicted SOM content. In the 0–50 cm tillage layer, the highest average SOM content of 39.73 g/kg was found under the NT-1 treatment with different no-tillage straw return year treatments. The depth of the tillage layer in the typical black soil region of Northeast China is around 0–20 cm, and the most significant increase in SOM content was observed in the experimental samples under the NT-1 treatment. SOM content in NT-1 treatment increased by 31.83% compared with CK-1, 68.24% compared with CK-2, 72.18% compared with NT-0, 699.48% compared with NT-2, and 311.44% compared with NT-3, respectively. The highest SOM content of 31.9 g/kg was found in NT-100 under the different treatments of different years of field return. At the 0–20 cm soil layer, the SOM content increases most significantly under NT-100 treatment, which is the most suitable treatment method for straw return to the field. And NT-100 is 22.09% higher than CK-1, 55.36% higher than CK-2, 58.99% higher than NC-0, 115.95% higher than NT-33, and 48.72% higher than NT-67, respectively. This study provides data that can support the conservation of soil ecosystem diversity and sustainable soil use, and it also enriches the application of the PLSR model application.

A novel fungal and bacterial consortium promotes the degradation of rice straw: Conditions optimization and degradation properties

The rapid development of agriculture has led to the production of a large amount of crop straw, necessitating effective strategies for its management. Microbial degradation offers a promising method. In this study, a novel microbial consortium composed of Phanerochaete chrysosporium, Aspergillus niger, and Streptomyces griseorubens, known for their robust lignocellulose degradation capabilities, was constructed for rice straw degradation. The establishment of this microbial consortium was based on the growth curve and antagonistic tests. Orthogonal optimization revealed that Streptomyces griseorubens played a predominant role in the degradation of rice straw. The optimal degradation conditions were determined as follows: nitrogen source concentration of 2.5 gL−1, material-liquid ratio of 40 g L−1, inoculum size of 3%, and pH value of 9. Under these conditions, the degradation efficiency reached 42% within 15 days. The decomposition of lignocellulosic components in the straw was confirmed through various characterization methods. Additionally, as the degradation process progressed, there was a noticeable decrease in protein-like substances and an increase in humic acid-like substances in the degradation solution.

Establishment and validation the DEM-MBD coupling model of flexible straw-Shajiang black soil-walking mechanism interactions

With the implementation of the conservation tillage policy, the farmland surface layer is covered with a large amount of straw, and the soil of the plowing layer is mixed with a small amount of straw, which makes it difficult for the walking mechanism of the agricultural machinery to obtain the required driving force, resulting in reduced driving stability and difficult to control. In response to the analysis of the mechanism of inter-operation with soil mixed with straw during the operation of the walking mechanism of agricultural implements, the problem is the lack of accurate and reliable discrete elemental models of flexible straw-Shajiang black soil-walking mechanism interactions. This paper takes the tracked walking mechanism as the research object and establishes the dynamics model of the tracked walking mechanism interacting with mixed straw soil based on the coupling algorithm of DEM (Discrete Element Method) and MBD (Multi-Body Dynamics). The intrinsic parameters of soil and straw were determined experimentally, and a discrete elemental model of the interaction between Shajiang black soil and flexible straw was established based on the EEPA (Edinburgh Elasto-Plastic Adhesion) model and the Bonding V2 model, which was optimally solved through in-laboratory bearing tests to obtain the following results: the soil particles surface energy, Δγ, was 12.74 J/m2, and the plastic deformation ratio, λp, was 0.45; Based on the physical test, the simulated stacking angle and slope slip test were used as evaluation indexes, which resulted in a coefficient of restitution of the upper soil and rubber of 0.501, a static friction coefficient of 0.428, and a rolling friction factor of 0.089; The coefficient of restitution of the lower soil and rubber was 0.459, the static friction coefficient was 0.478, and the rolling friction factor was 0.073; We established a DEM-MBD model of flexible straw-Shajiang black soil-walking mechanism interactions, and started a field validation test using the stress value of the soil after being crushed by a tracked vehicle as an evaluation index. The validation results show that, under the forward speed of 1 km/h, the relative error between the simulated and measured values of the stresses on the soil is 7.46 %. It indicates that this paper establishes an accurate and reliable DEM model for the interaction of flexible straw-Shajiang black soil-walking mechanism, which can provide a theoretical basis and technical reference for revealing the mechanism of interaction between the walking mechanism of agricultural machinery and the soil, the optimization of the structure of machinery and the selection of operating parameters.

Fungal Saprotrophic Promotion and Plant Pathogenic Suppression under Ditch-Buried Straw Return with Appropriate Burial Amount and Depth.

Fungi as heterotrophs are key participants in the decomposition of organic materials and the transformation of nutrients in agroecosystems. Ditch-buried straw return as a novel conservation management strategy can improve soil fertility and alter hydrothermal processes. However, how ditch-buried straw return strategies affect the soil fungal community is still unclear. Herein, a 7-year field trial was conducted to test the influences of burial depth (0, 10, 20, 30, and 40 cm) and the amount of ditch-buried straw (half, full, double) on the diversity, composition, and predicted functions of a soil fungal community, as well as the activities of carbon-degraded enzymes. Under the full amount of straw burial, the abundance of phylum Ascomycota was 7.5% higher as compared to other burial amount treatments. This further increased the activity of cellobiohydrolase by 32%, as revealed by the positive correlation between Ascomycota and cellobiohydrolase. With deeper straw burial, however, the abundance of Ascomycota and β-D-glucopyranoside activity decreased. Moreover, genus Alternaria and Fusarium increased while Mortierella decreased with straw burial amount and depth. FUNgild prediction showed that plant fungal pathogens were 1- to 2-fold higher, whilst arbuscular mycorrhizal fungi were 64% lower under straw buried with double the amount and at a depth of 40 cm. Collectively, these findings suggest that ditch-buried straw return with a full amount and buried at a depth less than 30 cm could improve soil nutrient cycles and health and may be beneficial to subsequent crop production.

Co-pyrolysis of Baltic wheat straw and low-density polyethylene bags and its kinetic and thermodynamic behaviour

Wheat cultivation represents about 42 % of the total cereal cultivation area in the Baltic Sea region, generating huge amounts of wheat straw (WS) that needs to be optimally managed. In this context, this research aims to investigate the extent of using pyrolysis process in WS valorization. The experiments were performed using a thermogravimetric (TG) analyzer on WS and its mixtures with low-density polyethylene (LDPE) bags at different mixing ratios (1:1, 1:2, 1:3, 1:4). The released TG vapours were monitored using TG-Fourier transform infrared spectroscopy (TG-FTIR) and chromatography-mass spectrometry (GC-MS). The thermochemical activation energy (Ea) were studied by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Friedman, and Vyazovkin models. The pyrolysis results showed that WS and LDPE could be completely decomposed as a single reaction up to 600 °C and 520 °C, respectively. Aromatic-carbonyl and CO2 were the main FTIR functional group for WS vapour versus -CH2- for LEDP vapour. The GC/MS analysis of WS showed various compounds such as sec-Butylamine (11.88 %), acetic acid (10.68 %), etc., while LDPE showed many compounds without specific trend even when the heating rate was changed. While the co-pyrolysis results showed that WS/LDPE could be decomposed individually in two successive reactions at 335 °C (WS) and 495 °C (LDPE). These results were confirmed by FTIR and GC/MS which showed that the functional groups and chemical compounds of vapour generated at these decomposition zones have similar characteristics to those obtained from pyrolysis of WS and LDPE. Finally, kinetic analysis showed that WS-Baltic (227–250 kJ/mol) is more complex compared to WS-Asian (163–217 kJ/mol) due to its higher ash content. While Ea of WS/LDPE was increases upto 274–291 kJ/mol (1:1), 266–297 kJ/mol (2:1), 268–289 kJ/mol (3:1), and 278–299 kJ/mol (1:4). Also, the enthalpy, and Gibbs free energy coefficients of WS were increased by mixing (1:1) up to 272 J/mol K, while its entropy does not change much by mixing (367 J/mol K). Accordingly, the co-pyrolysis process is a key technology in valorization of WS and convert into value-added chemicals and a sustainable energy source.

Efficacy of Imazapic in Controlling the Germination Fluxes of Rottboellia cochinchinensis (Lour.) Clayton Under Different Rainfall Levels and Sugarcane Straw Amounts

Efficacy of Imazapic in Controlling the Germination Fluxes of Rottboellia cochinchinensis (Lour.) Clayton Under Different Rainfall Levels and Sugarcane Straw Amounts

Herbicide runoff from a soil with different levels of sugarcane straw coverage in Brazil

This study evaluates the effects of different levels of sugarcane straw on the soil surface on the transport by runoff water of four herbicides: ametryn, diuron, hexazinone, and sulfentrazone. Two runoff experiments were conducted in a set of nine experimental plots. In the first experiment, sugarcane was cultivated and no straw was applied to the soil. In the second experiment, sugarcane was cultivated with straw levels of 0, 9, or 18 Mg ha-1 on the soil surface. The runoff water from natural rainfall was collected in reservoirs at the lower end of each plot on different occasions following the application of the herbicides to the plots. The total volume of runoff water collected from the plots was dependent on the coverage of the soil by straw, in the sequence: 0 &gt; 9 &gt; 18 Mg ha-1. For the herbicides hexazinone and sulfentrazone, which are molecules of high solubility in water, increasing the amount of straw on the soil produced an increase in the fraction of the applied dose appearing in the collected runoff water. However, for diuron and ametryn, which have low solubility in water, the presence of straw did not influence the amount found in the collected runoff water.