Soil Fragments Research Articles

Simulation and Experimental Study of the Tillage Mechanism for the Optimal Design of Wheat Rotary Strip–Tiller Blades

In order to clarify the mechanism of tiller–soil interaction in the process of strip rotary tillage, this paper conducted a simulation and experimental research on four blade configurations composed of three rotary blades (bent C, straight and hoe) at three rotation speeds (280, 380 and 510 rpm). The study found that the soil throwing characteristics of the blades are the key factors affecting the quality of tillage. The increase in the rotation speed not only improved the soil breaking effect, but also enhanced the phenomenon of soil throwing and then led to a reduction in the soil backfill. In the BC configuration (combination of four bent C blades), the bent C blades showed the best soil throwing characteristics and created the best soil fragmentation. However, due to the obvious side throwing of the soil, the backfill effect of soil fragmentation was the worst. The backfill rate was only 8% when the rotation speed was 510 rpm and could not allow reaching the required seed–soil contact during sowing. The hoe blades in the HC configuration (combination of four hoe blades) could collect part of the soil fragments and throw them towards the direction of the machine during the cultivation process, which led to a good soil breaking effect and a low soil side throwing rate. When the rotation speed was 510 rpm, 36% of the soil was backfilled into the seedbed. In the SC configuration (combination of four straight blades), the straight blades could well control the scattering of the side-thrown soil fragments. At a super-high rotation speed (510 rpm), the side throwing rate was only 70%, and the backfill rate was as high as 60%. However, the soil fragments created by the blades were too large (average soil block diameter > 40 mm) and could not form a loose and finely broken seedbed environment. The MC configuration (combination of two straight blades and two hoe blades) benefited from the combination of straight blades and hoe blades, offering outstanding advantages for backfill and soil fragmentation. Therefore, under the condition of a centralized configuration of field surface straw, it is recommended to use the MC configuration of the wheat rotary strip–till planter for cohesive paddy soil.

Study on the Soil Deterioration Mechanism in the Subsidence Zone of the Wildcat Landslide in the Three Gorges Reservoir Area

The stability of soil mass near the dam bank in the Three Gorges Reservoir is closely related to the periodic variation in the reservoir water level. In order to study the influence of water level variation on soil mass, the soil mass in the water level fluctuation zone of the Wildcat landslide was taken as the research object, and the mechanism of soil mass deterioration in this area was revealed by comparing the strength and mineral structure characteristics of soil mass at different elevations by means of macro- and meso-microscopic analysis. The results show the following: (1) With the increase in sampling elevation, the natural water content of the soil decreases, and the dry density of the soil is a minimum when the elevation is 155 m and at a maximum when the elevation is 175 m. (2) The soil mass in the water dissipation zone of the Wildcat landslide can be divided into three areas: When the elevation is 145–155 m, the fractal dimension increases, the soil fragmentation increases, the cohesion decreases, and the soil deterioration increases. When the elevation is 155–175 m, the fractal dimension decreases, the soil fragmentation decreases, the cohesion increases, and the soil deterioration weakens. When the elevation is greater than 175 m, there is no soil deterioration. (3) X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) were used to test the soil’s mineral composition and pore size at different elevations. It was found that the main reason for the severe deterioration of macro-strength parameters of the soil at the elevation of 155 m was that the proportion of clay minerals and quartz was at the lowest, and the proportion of medium pores and large pores was at the highest. (4) Through the combination of macro and mesoscopic testing and analysis, it was found that the rise and fall of the reservoir water level will lead to the strong chemical action of the skeleton and cemented mineral dissolution in the soil degradation-enhanced area, as well as the physical action of soil particles, resulting in the formation of more medium pores and large pores in the soil and eventually the formation of seepage channels.

Simulation of soil-tool interaction using smoothed particle hydrodynamics (SPH)

Numerical techniques in soil-tool interaction play a critical role in the applications of optimal design and optimal control of soil-engaging components. However, one of the greatest challenges in the simulation of soil-tool interaction is the complex dynamic behaviors of the soil in the regime of large deformations, and the analysis and evaluation of forces at the soil-tool interface. Recently smoothed particle hydrodynamics (SPH) has shown its advantages in modeling large deformation problems with deformable boundaries and moving interfaces. In this paper, an SPH model of soil-tool interaction based on the elastoplastic constitutive is established. Firstly, the cutting process and soil-tool interaction for both non-cohesive and cohesive soil are simulated based on a shear failure model and a contact algorithm. The simulation results for non-cohesive soil and cohesive soil in different operating conditions are discussed separately, and the results for different operating conditions are compared. In addition, interactions between soil and inclined short flat blades are also simulated to estimate the cutting force during the tillage process. The predicted soil configuration and cutting force are in good agreement with our experiments and with the results in published literature. The cutting forces for non-cohesive soil exhibit similar trends and average values throughout the process. For cohesive soil, the cutting force curve has a wavy trend and the average value in a stable state is greater than for non-cohesive soil. In order to further validate the feasibility and precision of the presented model, different tillage conditions (cutting angles and depths), internal friction angles for non-cohesive soil, different cohesion for cohesive soil, and different friction coefficient of the cutting blade are all discussed. This work has demonstrated that the proposed model is accurate in soil-tool interaction simulations and can also provide an accurate description of the shear fragmentation of cohesive soil. It helps to contribute to a better understanding of the tillage process that is fundamental and essential for the optimal design of the soil-engaging components.

BMOTSM: design of a hybrid bioinspired model to determine optimal turbine sizing for capacity maximisation in environment-and-economy aware deployments

ABSTRACT Multiparametric optimisation determines optimal turbine size for eco-friendly wind farm repowering. This involves identifying turbine ratings, repowering locations, and wind zone analysis for maximum economic efficiency and low environmental impacts. Existing models that perform these tasks are either highly complex or cannot be scaled due to deployment-specific characteristics. Most of these models do not consider economic or environmental impacts when repowering wind farms. This text discusses the design of a novel hybrid bioinspired model to determine optimal turbine sizing in environment- and economy-aware deployments. The model combines GWO, PSO, and GA to optimise turbine ratings, economic impacts, and environmental impacts during the repowering process. GA model optimises new turbine locations, while PSO maximises turbine efficiency. Both these models are internally optimised via GWO due to economic and environmental effects. The GWO model continuously tunes GA and PSO to find the best multiobjective repowering solution. The integrated model was validated on real-time wind farms to evaluate power conversion efficiency, deployment cost, soil fragmentation percentage, and cost-to-power ratios. The proposed BMOTSM model achieved 6.5% higher conversion efficiency, 8.5% lower deployment cost, 15.4% lower soil fragmentation, and 3.5% lower cost-to-power ratio than state-of-the-art models, making it useful for a variety of real-time wind farm repowering scenarios.

Development of an online gamma radiation measurement system

Raw coal is often interspersed with rocks as well as soil fragments, so natural γ-radiation measurement is used for online detection of coal quality in the coal mining and processing production process. To solve the problems of system development, data acquisition and transmission and online calibration in online γ radiation measurement, an online γ radiation measurement system was developed based on ATMEGA8L microcontroller. The upper computer software developed with Qt realizes the functions of RS485 serial communication between the upper computer and the lower computer, online configuration of the instrument working mode, real-time display and recording of the measurement results, and recording and query of the working log. After testing, the software of the upper computer is easy to operate, friendly human-computer interaction, and can realize the required functions to meet the current requirements for the intelligence of production instruments, and the RSD of the measurement results of the system is 1.1% for long time operation, with good stability.

Development law of soil cracks in karst peak-cluster depressions under dry and wet alternations

In an experiment with alternating dry and wet conditions of soil in cultivated land, orchards and forest lands with limestone and dolomite in karst peak depression, combined with digital image processing technology, we investigated the development law of soil surface cracks under alternating dry and wet condition. The results showed that with the alternation of wet and dry, the average width of cracks decreased at a fast-slow-slower rate, with an order of limestone > dolomite under the same land use, and orchard > cultivated land > forest soil under the same soil-forming parent rock. In the first four dry and wet alternations, the degrees of soil fragmentation and connectivity were higher in dolomite development than in limestone, with significant differences in fracture development rose diagrams. In the subsequent cycles, soil fragmentation of most samples increased, the difference dominated by parent rock gradually decreased, the crack development rose diagram converged, and the connectivity showed the pattern of forest land > orchard > cultivated land. After the fourth cycle, the alternations of dry and wet seriously damaged soil structure. The physical and chemical properties of capillary porosity and non-capillary tube porosity were dominant in the development of cracks before that, but it was more dependent on the organic matter content and the sand composition after that.

Химическая маркировка взрывчатых веществ для повышения безопасности взрывных работ

The article is devoted to the development of a marking composition for industrial explosives to improve the safety of blasting. Polymethylsiloxane liquids of PMS-10 and PMX-200 grades were chosen as a marker-identifier of industrial explosives, which can be identified even after the explosion by residual fragments of soil or other materials from the epicenter of the explosion. Polymethylsiloxane fluids are very heat-resistant, the combustion process takes place with great difficulty, they are little affected by the aquatic environment, most chemical and physical factors that destroy ordinary organic materials. The experiments were carried out to determine the physicochemical parameters of polymethylsiloxane liquids PMS-10 and PMX-200. Based on these results, the polymethylsiloxane liquid PMX-200 with linear chains was chosen as a marking additive in the composition of explosives. It is able to withstand a higher-temperature effect than the PMS-10 polymethylsigsane fluid, and will be less disintegrate, and interact with the products of the explosion. The SIM-K marker, made on the basis of polymethylsiloxane liquid PMX-200, was developed, which allows to visualize the explosive and determine the required identification information. At the technological plant of Orika-Kazakhstan JSC, without disturbing the technological process, a marking composition was introduced into the ANFO explosive by drop spraying. Field tests of the ANFO explosive with a marking composition based on PMX-200 polymethylsiloxane liquid were carried out. The technology was tested related to introduction of marking additives into the compositions of multicomponent explosives without violating the technological process of their manufacture.

Analysis of Cyperus esculentus–Soil Dynamic Behavior during Rotary Tillage Based on Discrete Element Method

Considering the problems of low soil fragmentation rates, high working resistance, and high energy consumption in the harvesting process of Cyperus esculentus in China, a method of Cyperus esculentus harvesting based on counter-rotation digging is proposed. The mechanism of interaction between the rotary tillage blade and Cyperus esculentus–soil is systematically investigated, and the vertical and horizontal disturbance performance of the positive and counter-rotating harvesting methods on soil and Cyperus esculentus is compared and analyzed. The results of the experiment showed that the intensity of soil and Cyperus esculentus disturbance by counter-rotation increased by 166.67% and 297.78%, respectively, and the effective disturbance time of soil and Cyperus esculentus increased by 133.33% compared to that of positive rotation. The working depth and rotation speed of the rotary tillage blade were the most significant for soil and Cyperus esculentus disturbance intensity. The working depth increased from 150 mm to 170 mm, and the soil disturbance intensity increased by 17.91% and 21.37% for positive and counter-rotating operation, respectively, and the rotation speed of the rotary tillage blade increased from 270 rpm to 330 rpm, and the soil disturbance intensity increased by 28.85% and 35.29%, respectively. Compared with the positive rotation operation, the Cyperus esculentus counter-rotation soil fragmentation rate increased by 4.09%, the Cyperus esculentus damage rate decreased by 10.69%, and the buried fruit rate decreased by 7.38%. This paper helps to understand the interaction mechanism between the rototiller and Cyperus esculentus–soil and lays a theoretical foundation for the subsequent design and optimization of the Cyperus esculentus digging device.

Sustainability in agribusiness: Analysis of environmental changes in agricultural production using spatial geotechnologies

As global populations grow the growing demand for food and food security also rises. As global climate change proceeds, a growing demand for sustainability in said food production concurrently grows. Initiatives that address sustainability in agribusiness can now utilize geotechnology to identify losses in environmental quality resulting from methods of food production. The objective of this study is to evaluate the risks of environmental transformations categorized as: savannah, urban, water, forests, exposed soil, cultivation and regrowth in the municipalities of Carazinho, Marau and Passo Fundo, located in southern Brazil, demonstrating the potential of the approach in the Process Analytical Hierarchy (AHP), integrated with Geographic Information Systems (GIS) to determine areas at risk of environmental degradation. This study considered parameters of density of rural buildings, soil type, use and slope. The AHP method was used to determine the weights of the parameters, through the following categories: savanna = 0.1; urban = 0.25; water = 0.9; kill = 0.1; exposed soil = 0.4; cultivation = 0.45; and regrowth = 0.5. The results showed that the integrated approach of AHP and GIS in a computerized environment proved to be effective for the mapping and quantification of environmentally degraded areas, attributed to the percentage of exposed soil, with the formation of sedimentary basins in river beds, with a high risk of 2.49%, with 2680 patches of exposed soil fragments identified. Exposed soil detracts from the sustainability of agricultural production in the region. This research is fundamentally important as it can be replicated in other regions, making it possible to assess environmental problems in relation to food production areas, aiming to raise the levels of agribusiness on a global scale.

RESEARCH ON SOIL FRAGMENTATION CHARACTERISTICS BASED ON FRACTAL DIMENSION AND IMAGE PROCESSING

To improve the complex process of judging the degree of soil fragmentation during potato-soil separation and to establish a fast and effective judging method. Soil drop experiments were performed using sandy soil from the potato growing region of Hohhot, Inner Mongolia Autonomous Region, China. The effects of soil moisture content, hardness, volume, drop height, inclination of the separating sieve and composition of the separating sieve rod on soil fragmentation were investigated. The fractal dimension and image processing used to quantify soil fragmentation and scattering and obtain quantitative indicators of soil fragmentation. The results showed that the following factors influenced soil fragmentation in descending order of statistical significance: soil hardness, fall height and soil volume. The softer the soil was, the greater the fall height; the larger the soil volume was, the greater the fragmentation. Meanwhile the correlation between the two indicators is extremely high, simplifying assessment of the degree of soil fragmentation. This study clearly shows the influence of the intrinsic physical properties of soil and the external physical parameters of potato excavators on the characteristics of crushed soil. The results can provide a basis for improving the efficiency of potato-soil separation and designing more efficient devices for harvesting potatoes.

Phosphorus content in water extractable soil colloids over a 2000 years chronosequence of paddy-rice management in the Yangtze River Delta, China

Soil phosphorus (P) is usually hardly present in soluble forms as most of it is strongly bound to minerals. Therefore, transformations of soil colloidal P can play a key role in enhancing soil fertility. Here, we examined water extracts from a chronosequence of soils with 2000 years of paddy rice and 700 years of non-paddy cropping, and fractionated them into <1200 nm, <450 nm, and <3 kDa size fractions using sequential ultrafiltration. Asymmetric-flow field-flow fractionation (AF4) coupled to an organic carbon detector (OCD) and inductively coupled plasma mass spectrometry (ICP-MS) was used for organic carbon and elemental screening in the 3 kDa-450 nm colloidal size range. We found that P increased in all colloidal fractions both with long-term paddy rice and non-paddy managements. Furthermore, P in soil colloids of 3 kDa-450 nm size, as fractionated by AF4, peaked in three size ranges: nanoparticles (NP, ∼3 kDa-20 nm), fine colloids (FC, ∼20–225 nm), and medium-sized colloids (MC, ∼225–450 nm). The NP fraction originally contained mainly P and Ca for tidal wetland (TW), but turned into a complex of OC-Ca-P colloidal forms immediately after onset of arable management, with little temporal change thereafter. Fine colloidal P (FC-P) was detected only after > 50 years for the non-paddy and > 100 years under paddy management, associated with oxides, organic matter and fine clay fragments in the paddy soils and additionally Ca-bound P in the non-paddy ones, respectively. Increasing portions of medium-sized colloidal P appeared after 50 years paddy and non-paddy management, though not exceeding the concentrations of FC-P and with little changes during prolonged arable land use. Overall, after initial formation of FC-P during the first 50–100 years of management, longer term dynamics of colloidal P in these arable soils was fairly independent of paddy or non-paddy managements, but remained closely coupled to the increased presence or generation of fine colloidal clays, oxides and the associated P, thus potentially linking P fertility largely to the dynamics of fine colloids.

Migration characteristics of chromium and organic compounds released from waste leather fragments in soil under rainfall

The environmental issues caused by chrome-tanned leather could not be overlooked, and the high concentration of chromium (Cr) in the waste leather fragments was a major factor in limiting its resource utilization. Few studies have reported the contamination of soil and groundwater by discarded leather fragments. Soil column and static leaching experiments were conductive to exploring the release and transport of organic compounds and Cr from waste leather fragments with various types and sizes. The findings revealed that the 1 cm2-sized leather fragments of cowhide released more organic compounds into the leachate than the pigskin with same size, whereas leather fragments of the pigskin released more Cr than those of the cowhide, and this phenomenon was more prominent under rainfall condition at pH 4.68 than at pH 5.86. The Cr concentration increased at first and then decreased in the leachate, while the concentrations of soluble protein (SP), free amino acid (FAA), and total organic carbon (TOC) increased with the leaching event. After leaching, the concentrations of SP and FAA in each soil layer were nearly three times higher in the leather treatment groups than in the leather absent groups. Cr(III) was the primary species existed in the deep soil layer. The impact of leather fragment type and size on the release of Cr and organic compounds into soil was assessed, which helped to guide waste leather fragment reuse, landfill procedures, and impermeability measure design.

Effect of Mounting Angle on Bending Subsoiling Tool–Soil Interactions Using DEM Simulations

Mechanical subsoiling is an effective practice to promote better water infiltration and crop root development. The bending subsoiling tool (BST) is a primary subsoiling tool and is used to remove soil compaction and restore soil productivity. In this study, a discrete element model was developed and validated using laboratory soil bin tests to investigate the effects of the mounting angle of the BST (5°–33°) on soil disturbance behaviors and draft forces. The results show that the upheaval, failure and fragmentation of soil was achieved by successive shearing, uplifting, extrusion, tension and turning actions from the cutting share and cambered shank of the BST. Increasing soil depths gave smaller soil disturbance ranges in lateral, forward and upward directions. With an increase in mounting angle, both the draft force and soil rupture distance ratio initially decreased and then increased, whereas the soil loosening efficiency initially increased and then decreased. Overall, increasing the mounting angle of the BST from 5° to 33° gave a greater soil surface flatness that increased rapidly when the mounting angle increased from 26° to 33°. Appropriately increasing mounting angle of the BST from 5° to 26° could lift more moist soil from the deep seed and middle layers (5.0–15.5% increase) into the shallow seed layer (depth of &lt;50 mm) without seriously affecting the mixing of the deep layer and other layers. Considering both the soil disturbance characteristics and draft forces, a mounting angle of 26° appeared to outperform the other angles.

Effects of topography and historical human disturbance on the current-day distribution of Betula davurica in a secondary deciduous forest in central Japan

ABSTRACT Betula davurica is a relict species in Japan of which distribution is influenced by topography at local scale. This species may also be dependent on disturbance for regeneration. However, no studies found that estimate and compare the effects of topography and human disturbance on abundance of this species. Focusing on abandoned charcoal kilns and charcoals in the surface soil as proxies for historical disturbance, we assessed the status of B. davurica in a secondary deciduous broad-leaved stand in central Japan. Although B. davurica was once a dominant species in the study area, its regeneration has stagnated after decline of charcoal production. The oldest individual was 90 years of age, suggesting that the current-day population established following a period of grassland dominance 100 years ago. We found multiple abandoned kilns, as well as widespread charcoal fragments in the surface soils of the study area. Both individuals, that had established prior to and following the decline of charcoal production, tended to be distributed at sites with other tree species with smaller DBH and at gentle slope. Location of charcoal kilns did not significantly affect the distribution of this species. It is possible that B. davurica prefers to gentle slope at the sites where historical logging for charcoal production and fire disturbance had influenced at the whole. Cessation of logging and fire disturbance have likely inhibited the regeneration of B. davurica. Logging of other tree species around at gentle slope may be necessary for the survival of this species.

Tillage-Induced Fragmentation of Large Soil Macroaggregates Increases Nitrogen Leaching in a Subtropical Karst Region

Tillage leads to rapid loss of soil nitrogen (N) over a short period of time in karst areas. N leaching is the primary pathway of soil N loss and therefore is key to understanding the mechanisms of N loss induced by tillage. However, the factors affecting N leaching under tillage are not fully understood. Effects of tillage at various frequencies on leached N were examined in a one-year in situ simulation experiment using five tillage treatments: no tillage (T0), semiannual tillage (T1), and tillage every four months (T2), two months (T3), and monthly (T4). Concentration and amount of leached N had peaks in dry–rewetting months. Tillage significantly increased total amounts of leached N during the one-year experiment, and the largest amount of leached N was under tillage at the highest frequency. The primary form of N in leachate was NO3¯ (88.49–91.11%), followed by DON (7.80–9.87%), and then NH4+ with the lowest amount (1.09–2.10%). Tillage increased the amount of leached NO3¯ and DON, but had no significant effect on leached NH4+. Additionally, the amount of leached N had significantly negative correlations with 5–8 mm soil aggregate, NO3¯, DON, and sand content, and positive correlations with 2–5 and 0.25–2 mm. Soil 5–8 mm aggregate and DON were the main factors explaining the variation in leached N according to the RDA analysis. Tillage increased the breakdown of large aggregates, appearing to have increased the mineralization of organic matter, which resulted in increased N leaching. Our results emphasize the importance of reducing or eliminating physical disturbance indued by tillage and maintenance of large soil aggregates for decreasing N leachate in lime soil of karst regions.

Fragmentation of soil-root complexes in sloping landscapes during tillage and soil translocation

It is well known that roots play a significant role in reducing water erosion in soil, yet few studies have reported the influence of crop roots on soil translocation induced by tillage in sloping fields. To examine the relationship between soil-root complexes (i.e., complexes of wheat roots and soil) and soil redistribution caused by tillage, a series of tillage experiments were carried out on bare soil and areas of wheat sown by drilling ( DS ) and nesting ( NS) using nine slopes with gradients varying from 0.19 to 0.32 m m −1 . The magnetic tracing technique was used to determine soil translocation rates under hoeing tillage in sloping landscapes in response to soil-root complexes and bare soil. The results indicated that mean displacement distance for DS and NS in the downslope direction was 0.15 m and 0.16 m, respectively. This was much shorter than that of bare soil which was 0.26 m. Mean tillage erosion rates ranged from 14.58 to 19.15 Mg ha −1 per tillage pass for DS and 13.90 –21.10 Mg ha −1 per tillage pass for NS , while reached 31.23–36.31 Mg ha −1 per tillage pass for bare soil. Tillage transport coefficients ( k 3 and k 4 ) were 6.31 and 106.46 kg m −1 per tillage pass for DS , 6.58 and 118.68 kg m −1 per tillage pass for NS , and 28.12 and 151.07 kg m −1 per tillage pass for bare soil, respectively. A significant difference in cohesive force ( C ) was found between DS ( NS ) and bare soil ( P < 0.05), thereby resulting in an increase in the soil shear strength of soil-root complexes. Compared with those of bare soil, the soil fractal dimension of soil-root complexes decreased significantly due to an increase in the percentage of coarse clods (>100 and 100–80 mm) and a decrease in the percentage of fine clods (50–20 and < 20 mm). Mean soil displacement distance caused by tillage displayed a negative relationship with C and wheat root traits (the root density, the root length density, and the root area ratio) within the hilly landscape of soil-root complexes ( P < 0.05), implying that wheat roots played a crucial part in soil translocation and soil fragmentation during hoeing tillage. Our study revealed that soil-root complexes markedly reduce the soil downslope transfer process during tillage and prevent the break-up of large clods by tillage implements on sloping farmland. • Wheat root attenuated the mechanical breakage of clods during tillage operation. • Root systems increase soil shear strength and reduce fragmentation of soil clods. • Displacement distance for soil-root complexes was smaller than that for bare soil. • Tillage erosion decreased with increasing structure stability and cohesive force.

Effects of Tillage Methods on Crop Root Growth Trend Based on 3D Modeling Technology

Strip rotary tillage seeding technology has been widely used in rice–wheat rotation system, benefiting the economy greatly. The purpose of farming is to create a comfortable seedbed environment for crop growth. Therefore, it is necessary to consider the effects of tillage methods on wheat root configuration and growth trend in the research of strip tillage, instead of just focusing on optimizing the shape of tillage tools, sowing methods, and soil fragmentation. To clarify the effects of different tillage methods on crop root growth trends, a two-year wheat planting experiment was carried out. Strip tillage (ST1 and ST2) and full width tillage treatment (FT) were designed, 3D models of root structure and soil on the surface of the seedbed wall were established, and four quantitative indexes were proposed: soil surface roughness of seedbed wall (SR), difference coefficient of root soil space occupation (P), difference coefficient of root angle expansion trend (PA), and difference coefficient of root length expansion trend (PL). The results showed that the cultivation method directly affects the growth trend of wheat roots. The wheat roots tended to grow along the inter-specific direction under ST treatment on the 14th day, and the average P, PA, and PL were as high as 38, 43, and 55, respectively. The SR produced by ST1 treatment was 70% lower than that of ST2 treatment, suggesting ST1 treatment had more serious restrictions on root growth. P, PA, and PL in ST1 treatment were 38.5%, 14%, and 43% higher than those in ST2 treatment within 14 days, respectively. This paper briefly explains the effects of tillage methods on the growth trend of wheat roots, provides new methods and technologies for the rapid and effective acquisition of soil surface information, solved the problem of the trend of root expansion being difficult to quantify, and provided a new direction for the optimization of tillage methods.

Requirements and Indicators of the Energy and Capacity for Some Secondary Equipment to Prepare the Soil and Fragmentation Index of Soil

A survey was carried out in the field of the Faculty of Agriculture, Basra University. The mechanical field try was done by isolating the field’s property as indicated by the Randomized Completely Block Design (R.C.B.D) included two factors, the first factor uses two primary tillage implements was mounted moldboard plough and digger plough, and second factor was four kinds of auxiliary culturing implements: Disk harrows, Axe harrows, spring cultivator and Rotary plough. The research was conducted in silty loam soil to investigate the influence of fuel consumption, traction force, field efficiency and the soil Fragmentation index. The purpose of this study was to investigate the influence of trowel type on the performance indicators of mechanical units to adapt them to the soils studied. The use of agricultural machinery contributed significantly to reducing the time, costs, effort and wages of workers in the field. The most prominent of these processes are the primary and secondary preparation of the soil and the mixing of manure residues with the surface layer of the soil. In this research, the superiority of the rotary plow over the rest of the machines was observed by recording the lowest pulling force and the lowest fuel consumption rate that it needs while moving and it was 1.60 kN and 14.42 L. ha-1 respectively, in addition to that giving it the best field efficiency and the best fragmentation degree and it was 68.66%, 6.5 mm respectively.

Effect of Tillage Depth and Lateral Distance of Shallow Plows on the Mean Weight Diameter and the Energy of Soil Fragmentation by Using Locally Manufactured Subsoiler Plow

The field experiments were carried out in Basrah province, to study the effect of the distance between the shallow plows (0.40, 0.50, 0.60m), and adding wings on the foot of the subsoiler plow, at tillage depth (0.30, 0.40, 0.50, 0.60m) on the Mean Weight Diameter (MWD) and equivalent energy of the soil fragmentation in clay soil. The results showed that the increase in the plowing depth to 0.60m by the subsoiler without wings on the foot and shallow plows gave largest of the MWD (102.28mm). While the increased the lateral distance of the shallow plows to 0.60 m gave MWD (67.13mm). The interaction effect of adding wings and tillage depth led to decrease MWD by 30% when adding wings compared to the no addition treatment. The MWD decreased by more than half with adding wings and shallow plows. The equivalent energy increased by 30.58% when increasing plowing depth from 0.30 to 0.60m compared to 9.09% for the no winged plow. Moreover, the equivalent energy of fragmentation decreased when increases lateral distance of the shallow plows. The equivalent energy increased by 36.29% when increasing the depth of tillage from 0.30 to 0.60m at lateral distance 0.60m compared to 9.09% for the plow without wings.

Characterization of Soil-Plant Leaf Nutrient Elements and Key Factors Affecting Mangoes in Karst Areas of Southwest China

Baise city is one of the largest producers of mangoes, with this agricultural industry located in the karst region of Southwest China. However, calcium-rich and alkaline soils, severe soil fragmentation, and poor water and fertilizer retention capacity contribute to low mango yields and are key issues that limit the development of the mango industry in karst areas. Our study objectives were to identify the soil factors that limit mango growth and yield in the karst region of Southwest China, and to determine how these growth- and production-limiting conditions vary between landscape positions. This study analyzed the differences in soil nutrient and element contents in mango leaves, and used a Random Forest algorithm to calculate the eigenvalues of the mango leaf and soil elemental indices in the different geomorphic parts (slopes, transition zone, passes, high-yielding depressions, and low-yielding depressions) of the karst peak-cluster depressions. The key factors affecting the mango leaves and soil were screened based on the diagnostic results and the eigenvalues. The results showed that for the elemental contents of Fe, Mg, Ca, and Mn in the mango leaves in the different geomorphic parts of the karst, the peak-cluster depressions were generally deficient and varied significantly. The contents of available B (AB), soil organic matter (SOM), pH, total nitrogen, available Fe, available Mn, alkaline hydrolysis nitrogen, exchangeable Ca (Caex), exchangeable Mg, and other indices in the soils differed significantly, and AB, available Zn, and available K (AK) showed low or very low content levels. In addition, the key soil factors limiting mango yield in the karst areas were AB, fulvic acid, SOM, Fe, Mn, Caex, soil water, and AK; and the key mango leaf factors were Ca, Mn, Fe, Zn, and Mg. Consequently, the characteristics of soil water content, pH, and soil organic matter may be the main drivers affecting the differences in the mango yield and the elemental characteristics. These findings suggest that the addition of organic fertilizer could improve the quality and yield of mangoes in karst areas.