Soil Loosening Research Articles

How different soil surface treatments in urban areas affect soil pore structure and associated soil properties and processes

Soil water and temperature regimes in urban environments are greatly affected by different surface treatments, and these may lead even to changes in soil properties. The goal of this study was to find out how soil properties had changed after 8 years of soil surface modification. Five surface treatment scenarios were considered: bare soil (BS), bark chips (BC), concrete paving (CP), mown grass (MG), and unmown grass (UG). X-ray computed tomography and micromorphological analyses showed that character of pores in soils with grass (MG, UG), which were mainly influenced by organisms living in soils and roots, differed from pore character in soil covers BC or CP, which mostly were impacted by organisms living in soils. Both groups differed from BS, which was predominantly affected by the regular treatment consisting in weed removal and soil loosening. Soil under BC was more compact than for other treatments due to decomposition of the bark chips mulch and migration of mulch components. Organic matter content was greatest but its quality lowest in the BC soil, followed by UG, MG, CP, and BS. The highest aggregate stability assessed using the water-stable aggregates (WSA) index was found for UG, followed by MG, BC, CP, and BS. The greatest water retention ability was observed for BC followed by UG, MG, CP, and BS. The unsaturated hydraulic conductivities for pressure head of –2 cm measured for UG, MG, and BS were much higher than were those for CP and BC. Finally, the greatest net CO2 efflux was measured for BC and MG, followed by UG, CP, and BS. CO2 emission correlated negatively with soil physical quality expressed as slope of the soil water retention curve at its inflection point. In general, the best soil conditions were observed for UG. No treatment considerably aggravated soil condition.

Design and Experiment of an Inter-Row Weeding Machine Applied in Soybean and Corn Strip Compound Planting (SCSCP)

To address the lack of specialized machinery for the mechanical weeding of SCSCP in the Huang Huai Hai region, this study designs a mechanized inter-row weeding machine for SCSCP. The machine features a reciprocating weeding shovel and an adaptive contouring mechanism for cultivation and soil loosening. This paper details the machine’s principles by analyzing the geometric relationship and mechanical model between the corresponding profiling quantities, which determine the relevant parameters for adaptive contouring to ensure stable operation on undulating ground. Furthermore, by optimizing the design of the weeding shovel’s reciprocating motion mechanism, combining EDEM simulation with the weeding shovel–soil interaction, it has been determined that, at various PTO shaft speeds, the optimal weeding efficacy is achieved with a blade-type weeding shovel structure when operating at a forward speed of 3.5 km/h. Field experiments were conducted with different PTO shaft speeds and weeding depths, using weeding and seedling injury rates as performance indicators. The results showed that, based on the optimal speed, the PTO shaft speed is 760 r/min, the operating depth is 3–5 cm, and the average row weeding rate is 90.4%. The average soybean and corn seedling injury rate is 3.4% and 4.2%, meeting the technical requirements for mechanical weeding.

Problems of Abandoning Deep Soil Loosening and Economic Efficiency of Technical Means for Loosening the Subsoil Horizon

The problems of refusal from deep soil loosening are analyzed, the parameters of effective chisel plows and subsoilers tested at machine-testing station are presented. The modes and functional indicators of their work as part of machine-tractor units are given; the comparative analysis of economic assessment indicators is performed.

Evaluation of sand subgrade seepage erosion caused by buried pipeline leakage

Leakage from buried pipelines can lead to an increase in the water content of the subgrade soils and a rise in the water table, leading to soil loosening, erosion and ultimately the formation of hidden voids and roadway collapses. This study presents a discrete-element method and validates its accuracy by utilising cavity data from model experiments. It investigates the mechanism of seepage erosion resulting from pipe leakage and analyses the development of the soil arch effect. Furthermore, it discusses the influence of sand void ratio and particle size on sand seepage erosion. The results indicate that the erosion area is primarily affected by the void ratio and particle size. In comparison to soil particles ranging from 0.1 to 5 mm and from 2 to 5 mm, those with sizes between 0.1 mm and 2 mm generate areas of erosion and loosening that are approximately 40% larger. The proposed model offers a precise analysis of the developmental process and the extent of seepage erosion, thereby contributing to the prediction of potential road cavity areas based on dynamic changes in key factors such as subgrade soil type and groundwater level.

Development of a Method for Soil Tilth Quality Evaluation from Crumbling Roller Baskets Using Deep Machine Learning Models.

A combination tillage with disks, rippers, and roller baskets allows the loosening of compacted soils and the crumbling of soil clods. Statistical methods for evaluating the soil tilth quality of combination tillage are limited. Light Detection and Ranging (LiDAR) data and machine learning models (Random Forest (RF), Support Vector Machine (SVM), and Neural Network (NN)) are proposed to investigate roller basket pressure settings on soil tilth quality. Soil profiles were measured using LiDAR (stop and go and on-the-go) and RGB visual images from a Completely Randomized Design (CRD) tillage experiment on clay loam soil with treatments of roller basket down, roller basket up, and no-till in three replicates. Utilizing RF, SVM, and NN methods on the LiDAR data set identified median, mean, maximum, and standard deviation as the top features of importance variables that were statistically affected by the roller settings. Applying multivariate discriminatory analysis on the four statistical measures, three soil tilth classes were predicted with mean prediction rates of 77% (Roller-basket down), 64% (Roller-basket up), and 90% (No till). The LiDAR data analytics-inspired soil tilth classes correlated well with the RGB image discriminatory analysis. Soil tilth machine learning models were shown to be successful in classifying soil tilth with regard to onboard operator pressure control settings on the roller basket of the combination tillage implement.

Effective strategies for reclaiming soda-saline soils: Field experimentation and practical applications in Southeast Kazakhstan

Soda-saline soils pose significant challenges to agricultural productivity, particularly in regions like the foothill plain of the Ili Alatau in southeast Kazakhstan. In this study, we examined the effectiveness of different ameliorants, including phosphogypsum, elemental sulfur, and sulfuric acid, in reclaiming soda-saline soils and enhancing crop yields. The study was conducted under real climatic and production conditions at the "Amiran" LLP farm. Using a randomized complete block design, we assessed the impact of these ameliorants on soil composition and alfalfa yield over two cutting cycles. The experiment involved the application of phosphogypsum, elemental sulfur, and sulfuric acid to designated plots within the farm, each covering an area of 15m2. Soil samples were collected before and after treatment to assess changes in soil composition and salinity. Alfalfa, a resilient perennial crop, was selected for cultivation due to its tolerance to adverse soil conditions. Our findings reveal that all tested ameliorants successfully neutralized the toxic environment of soda-saline soils, resulting in improved soil conditions and increased crop productivity. Phosphogypsum treatment led to a reduction in bicarbonate and carbonate ions, an increase in sulfate ion concentration, and improved soil structure. Elemental sulfur incubation decreased bicarbonate and carbonate ions, further reducing absorbed sodium levels and enhancing soil fertility. Sulfuric acid treatment provided rapid results in reducing alkalinity and increasing sulfate ion concentration, leading to significant improvements in soil quality and crop yield. However, the reclamation of soda-saline solonetzes presented challenges related to soil heterogeneity and poor water permeability. To address these challenges, we recommend the implementation of mechanical destruction of the solonetz soil horizon and deep soil loosening, accompanied by the addition of ameliorants. In conclusion, our study demonstrates the potential of phosphogypsum, elemental sulfur, and sulfuric acid as effective ameliorants for reclaiming soda-saline soils and improving agricultural productivity in challenging environments. By adopting recommended reclamation strategies, farmers can overcome soil limitations and achieve sustainable crop production in regions affected by soda-saline soil degradation.

Performance of cut-off walls under long-term vacuum suction: A case study

This study assesses the performance of cut-off walls in a vacuum preloading project at Lianyungang Port, China, to tackle challenges posed by ultra-soft reclaimed land. It investigates the walls’ impermeability and structural integrity by analyzing changes in hydraulic conductivity, in-situ lateral displacement, particle size distribution, and dry density both before and after vacuum suction. The introduction of a hydroxypropyl starch-based coupling agent (CA) in slurry reduces the hydraulic conductivity in the sandy matrix. Significant lateral displacement near the surface amplifies the likelihood of cracks, which lead to increased hydraulic conductivity. The cut-off wall is characterized by three zones: an erosion zone with large amount of fine particle mobility, a central effective zone with minimal deformation, and an outer tensile zone whose soil loosening leads to impermeability reduction. These findings provide valuable insights into the design and construction of cut-off walls for similar geotechnical applications and aid in forecasting the performance and lifespan of the cut-off wall.

Short‐term effects of double‐layer ploughing reduced tillage on soil structure and crop yield

AbstractSoil tillage is widely acknowledged to affect soil characteristics and agricultural productivity. This research investigates the short‐term effects of various tillage methods on soil physical properties and crop yields at a Central German field site with a dry climate (mean temperature 9.5°C; annual precipitation 470 mm). Three tillage approaches were evaluated: conventional plough tillage (25 cm depth), cultivator tillage (18 cm depth), and double‐layer plough tillage (15 and 30 cm depth). We assessed soil physical properties through standard laboratory analyses, compression tests, soil pore structure via X‐ray computed tomography (X‐ray CT) and crop yields over 3 years. The results indicate that cultivator tillage approach increased soil bulk density relative to conventional tillage, especially in the second year, though this effect diminished over time. Double‐layer plough tillage emerged as a viable short‐term alternative to conventional tillage, achieving comparable soil bulk density. Saturated hydraulic conductivity values were generally higher for soils under conventional tillage or double‐layer plough tillage than for cultivator tillage, highlighting their soil loosening effect. Classical soil analysis methods combined with X‐ray computed tomography provided valuable insights into tillage induced changes to soil structure. Cultivator tillage resulted in a distinct pore structure with reduced macroporosity and pore connectivity. Despite notable soil property variations, crop yields remained consistent across the tillage methods. Overall, double‐layer plough tillage presents a sustainable option, moderately improving soil physical properties while maintaining crop yields. This study highlights the need to assess the short‐term effects of tillage on soils and contributes to the broader dialogue on optimizing tillage strategies for effective soil management and crop production.

SIMULATION OF SOIL LOOSENING PROCESSES WITH COMPRESSED AIR

A model for describing soil loosening when exposed to compressed air is considered. The model allows you to calculate, depending on the compressed air pressure, the diameter of the hole and the depth of the feed point, the dilatancy zone (the area within which the created stresses will exceed the threshold and the loosening process will begin). The developed model is also used to describe soil loosening at several air supply points and at different jet directions.

Burial and subsequent growth of rigid ryegrass (Lolium rigidum) and ripgut brome (Bromus diandrus) following strategic deep tillage

AbstractSoil amelioration via strategic deep tillage is occasionally utilized within conservation tillage systems to alleviate soil constraints, but its impact on weed seed burial and subsequent growth within the agronomic system is poorly understood. This study assessed the effects of different strategic deep-tillage practices, including soil loosening (deep ripping), soil mixing (rotary spading), or soil inversion (moldboard plow), on weed seed burial and subsequent weed growth, compared with a no-till control. The tillage practices were applied in 2019 at Yerecoin and Darkan, WA, and data on weed seed burial and growth were collected during the following 3-yr winter crop rotation (2019 to 2021). Soil inversion buried 89% of rigid ryegrass (Lolium rigidum Gaudin) and ripgut brome (Bromus diandrus Roth) seeds to a depth of 10 to 20 cm at both sites, while soil loosening and mixing left between 31% and 91% of the seeds in the top 0 to 10 cm of soil, with broad variation between sites. Few seeds were buried beyond 20 cm despite tillage working depths exceeding 30 cm at both sites. Soil inversion reduced the density of L. rigidum to <1 plant m−2 for 3 yr after strategic tillage. Bromus diandrus density was initially reduced to 0 to 1 plant m−2 by soil inversion, but increased to 4 plants m−2 at Yerecoin in 2020 and 147 plants at Darkan in 2021. Soil loosening or mixing did not consistently decrease weed density. The field data were used to parameterize a model that predicted weed density following strategic tillage with greater accuracy for soil inversion than for loosening or mixing. The findings provide important insights into the effects of strategic deep tillage on weed management in conservational agricultural systems and demonstrate the potential of models for optimizing weed management strategies.

Microscopic insights into suction bucket installation in sand: Coupled coarse-grained CFD-DEM simulations

Suction bucket foundations are being used for a wide variety of offshore foundations. However, accurate modeling of its installation remains challenging due to the complexity of soil transportation, in which the soil is typically treated as a continuum and its discrete behavior is neglected. In this paper, the bucket foundation installation in the sand under different installation methods (i.e., jacked and suction-assisted installation) is investigated from a microscopic perspective (i.e., particle scale) based on the three-dimensional coupled computational fluid dynamics (CFD) and coarse-grained discrete element method (CGDEM). It is found that the CFD-CGDEM method can successfully simulate the bucket installation process. Suction-assisted installation results in a significant reduction in the inner skirt friction resistance and end resistance, while the outer skirt friction resistance shows only a minor decrease. During suction-assisted installation, soil loosening inside the bucket contributes more significantly to the soil plug formation compared to the inflow of external soil. Compared to jacked installation, the seepage induces a significant reduction in the effective stress of soil within the interior and below the bucket tip, while it increases the effective stress outside slightly under suction-assisted installation. The work provides an alternative research approach for the suction bucket installation.

Performance Evaluation of a Cicada-Inspired Subsoiling Tool Using DEM Simulations.

Subsoiling practice is an essential tillage practice in modern agriculture. Tillage forces and energy consumption during subsoiling are extremely high, which reduces the economic benefits of subsoiling technology. In this paper, a cicada-inspired biomimetic subsoiling tool (CIST) was designed to reduce the draught force during subsoiling. A soil-tool interaction model was developed using EDEM and validated using lab soil bin tests with sandy loam soil. The validated model was used to optimize the CIST and evaluate its performance by comparing it with a conventional chisel subsoiling tool (CCST) at various working depths (250-350 mm) and speeds (0.5-2.5 ms-1). Results showed that both simulated draught force and soil disturbance behaviors agreed well with those from lab soil bin tests, as indicated by relative errors of <6.1%. Compared with the CCST, the draught forces of the CIST can be reduced by 17.7% at various working depths and speeds; the design of the CIST obviously outperforms some previous biomimetic designs with largest draught force reduction of 7.29-12.8%. Soil surface flatness after subsoiling using the CIST was smoother at various depths than using the CCST. Soil loosening efficiencies of the CIST can be raised by 17.37% at various working speeds. Results from this study implied that the developed cicada-inspired subsoiling tool outperforms the conventional chisel subsoiling tool on aspects of soil disturbance behaviors, draught forces, and soil loosening efficiencies. This study can have implications for designing high-performance subsoiling tools with reduced draught forces and energy requirements, especially for the subsoiling tools working under sandy loam soil.

Combined Unit for Tillage with Pulsed Shock Wave Action

The paper shows that incorporating a multifunctional combined unit with pulsed shock wave action into soil tillage presents a pertinent and promising advancement in the soil cultivation system. (Research purpose) The research aims to develop a multifunctional combined unit for soil tillage integrating pulsed shock wave action. The objectives include enhancing productivity, refining tillage quality and promoting ecological considerations. (Materials and methods) The unit consists of a main frame, two side-folding sections, and a central section, which is made featuring a carriage, support and transport wheels. Additionally, it incorporates a frame in the shape of a hollow shaft, connected to a compressed air cylinder. The front frames of each section are equipped with rigidly fixed working bodies taking the form of cultivator paws with embedded pneumatic tubes. These tubes have outlet holes positioned at the ends of the wings of the paws, with a compressed air effective radius of 5-10 centimeters. (Results and discussion) The established ratio between the depth of surface tillage using a cultivator paw and the depth of subsoil tillage through pulsed blows of compressed air is 1:2. The tillage devices are supplemented by disc cutters with a diameter ranging from 25 to 30 centimeters, along with harrows designed for processing to a depth of 5-7 centimeters. (Conclusions) Enhanced by this modification, the design of the multifunctional combined unit enables the simultaneous execution of multiple operations, including cultivation with weed destruction, soil loosening using high-pressure air flow, and surface milling and grinding.

Crop-Livestock Integration Improves Physical Soil, Agronomic and Environmental Aspects in Soybean Cultivation.

Soybean is one of the most widely grown crops in the world and technologies are increasingly needed to increase productivity without impacting environmental degradation. In this context, the aim was to evaluate the action of forage plants of the genus Brachiaria sp. in crop-livestock integration on physical soil, agronomic and environmental aspects of soybean cultivation. The experiment was conducted in a subdivided plot design with seven integrated systems corresponding to the previous cultivation of Paiaguas palisadegrass, Xaraes palisadegrass and Ruziziensis grass in monocropping and intercropped with maize, as well as maize in monocropping. In the subplots, two grass management systems were evaluated: free growth and a grazing simulation cut. The bulk density and least limiting water range were assessed using soil samples and, after the pastures were desiccated when the soybean crop was planted, straw decomposition and plantability. A soil physics diagnosis by the bulk density and least limiting water range showed that the Paiaguas palisadegrass and Xaraes palisadegrass improved the soil environment due to biological soil loosening. The remaining mulch biomass did not affect soybean sowing and the adoption of Brachiaria sp. grass in the off-season, in addition to contributing to the provision of environmental services, and did not compromise grain productivity in succession.

A review on compaction and loosening of agricultural soils

Many soil experts and farmers are very concerned about the hard soil layers of agricultural soils. A layer known as hard soil is created when soil is compacted repeatedly over a long period of time. A type of physical soil degradation known as soil hardening modifies soil structure, restricts air and water penetration, and lessens root encroachment. These effects on the crust of the earth are still not fully understood. Therefore, to solve the worldwide dilemma of future food security, a thorough understanding of the subsurface processes is required. Compaction research must also be taken seriously because climatic conditions are shifting as a result of climate change, opening the door for the creation of novel mechanical tillers that can address compression problems. As a result, the focus of this study is on investigating the type, traits, causes, and effects of soil compaction on agricultural production as well as potential remedies using soil tillage.

Cover crops and soil loosening are key components for managing P and C stocks in agricultural soils

AbstractAgricultural soils have accumulated phosphorus (P) and lost carbon (C) in the recent decades. Simultaneously, soil structure has been degraded by the large increase in machinery weight. High wheel loads compact the subsoil, resulting in reduced root growth, decreased yields, and hence decreased C inputs and P removals. To reduce the accumulated excess P stock, the P balance should be kept strongly negative for decades, which requires high biomass production. P accumulation in poorly yielding field parts has created local hotspots, often characterized by soil compaction and poor drainage. They may be only 1%–6% of the agricultural landscape area but present a high risk for waterbodies. Identifying and targeting these hotspots for P removal can be a key strategy for mitigating P emissions. Achieving the P removal is most likely to require soil loosening to repair the damage caused by compaction and use of cover crops to mine out the accumulated P. This soil improvement strategy can also be beneficial for C sequestration and crop productivity. This commentary highlights the current status and recent developments in the interactions between compaction, cover crops and P loss to provide a research basis for developing landscape‐level strategies.

The influence of deep loosening on the ecological and meliorational state of drained mineral soils

The existing problems of energy, water, and food crises and climate changes determine the need to implement appropriate adaptive measures to improve the ecological and reclamation state of drained mineral soils. For the application of deep loosening of the soil as an adaptive agromelioration measure, a transition from traditional crack loosening of the soil and strip loosening of the soil to improved technologies of continuous layer-by-layer loosening of the soil based on energy-efficient and moisture-regulating principles is proposed. Their comparative evaluation according to the main indicators of overall efficiency was carried out on drained mineral soils of a representative object in the Western Polissia zone of Ukraine. According to the results of the evaluation of various technologies of deep soil loosening, it was determined that the technologies and technical means of continuous deep loosening of the soil have an advantage in all main indicators: agrotechnical, water-physical, energy, technological, ecological, and economic. In particular, the moisture availability of the soil increased by 27 % due to better accumulation of atmospheric precipitation, the yield of cultivated crops also increased by 20-30 %, and the aftereffect period increased to 4 years. This is a cost-effective and investment-friendly adaptive measure to ensure a satisfactory ecological and reclamation state of drained mineral soils (with an investment payback of 1 year). This provides modern principles of adaptive land use in changing climatic conditions and can be an effective alternative to expensive reconstruction and modernization of existing drainage systems.

Wood-derived lignocellulose nanomaterials as multifunctional agents in eco-friendly pickering emulsion-based drilling fluids

Emulsion-based drilling fluids are critical in the development of oil and natural gas from unconventional reservoirs due to their superior wellbore stabilizing capacity, good erosion resistance, and excellent lubricity. However, their widespread applications have been limited by the stringent environmental regulations and poor emulsion stability caused by hazardous, non-biodegradable oils and surfactants that have weak tolerance to temperature, pH, and salts. To address these concerns, an eco-friendly and high-performance Pickering emulsion-based drilling fluid has been developed, which includes sunflower seed-derived biodiesel as the oil phase, wood-derived lignocellulose nanomaterials (i.e., cellulose nanofibers-CNFs, cellulose nanocrystals-CNCs, and lignin nanoparticles-LNPs) as solid stabilizers, and bentonite as viscosifiers and fluid loss reducers. By tailoring the physicochemical characteristics and the synergistic effect of lignocellulose nanomaterials, the droplet size and stability of the emulsion can be well adjusted. The as-formulated drilling fluid exhibits desirable rheology and filtration performance, and can be used to cultivate paddy rice without treatment. The introduction of CNFs promotes soil loosening and nutrient absorption, leading to enhanced cultivation performance. This work may open a new avenue for the development of eco-friendly and high-performance drilling fluids using fully biomass-derived feedstocks.

Modeling and quantification of soil compaction promoted by animal trampling in an integrated crop–livestock system

At critical levels, animal trampling can physically degrade soil, leading to the loss of sustainability of agricultural production. Therefore, it is becomes necessary to model and quantify the soil compaction potential. In this context, the objective was to evaluate the occurrence of soil compaction promoted by animal trampling in crop-livestock integration system (ICL). The study was conducted in a field at Centro Tecnológico da Comigo in the municipality of Rio Verde, Goias state, Brazil, during the agricultural off-season. The experimental area was composed of 1.97 ha, which was equally divided into eight paddocks. Soil was sampled before the grazing phase and after each of four grazing cycles. The compressive behavior of the soil was evaluated by determining the pre-consolidation and critical pressures. The results showed that only the first cycle of grazing showed additional compaction in 14.59% of samples. No critical compaction was observed in the evaluated area. Animal trampling under the studied conditions is not responsible for the dissemination of structural soil degradation in crop-livestock integration systems and may contribute to physical improvement resulting from biological soil loosening.

Geocell-reinforced bed anchored with additional vertical elements under repeated loading

This paper investigates the behavior of geocell-reinforced beds combined with extra vertical elements embedded into the geocell pockets at their joints. During repeated loading, the soil mass inside geocell pockets can loosen, leading to decrease in geocell layer extension. Vertical elements can help to reduce the soil loosening, alleviate deformation and distortion of the geocell wall directly under loading zone and provide anchorage at the geocell outer boundaries. Results show that, with the use of vertical elements, geocell performance is significantly enhanced due to better load distribution and extra anchorage. An average 40% reduction in cyclic settlement was observed using combined geocell and vertical elements compared with a bed reinforced with geocell alone. Also, with an optimum height of the vertical elements, a 42% reduction in geocell consumption even at higher performance can be achieved using a less extensive geocell mattress. Provision of vertical elements caused the geocell length on each side of the footing to be decreased from 1.1D to 0.5D for the same performance in some cases (D: footing diameter). Prototype experiments showed that the geocell reinforcement anchored with vertical elements experiences less deformation, distributing load over a wider area. Thus, geocell and vertical elements combine to act like a geocell with greater thickness and larger width, helping project economy by lower use of geocell material even if the additional cost of vertical elements may counteract. Calibrated numerical modelling compared favorably with experimental observations, providing insight into stress and strain distribution in the soil and geocell.