Effects Of Soil Compaction Research Articles

How does soil compaction alter nitrous oxide fluxes? A meta-analysis

Nitrous oxide (N2O) is a potent greenhouse gas and precursor of ozone layer depletion. Managed terrestrial ecosystems are major anthropogenic sources of N2O, primarily generated in the soil. The physical makeup of the soil interplays with the underlying biochemistry that produces N2O. Therefore, it has been conceptualized that either compacting or loosening the soil will alter N2O emissions; however, a unified framework of these relationships is yet to be established. Here, we compiled, reviewed and analyzed available field studies that have evaluated how applied compaction or alleviation of compacted soils impacts N2O emissions. Of the 108 available pairwise comparisons, 82 % of the cases showed detrimental increases in N2O emissions caused by increased compaction. Overall, N2O emissions nearly doubled because of soil compaction effects (P < 0.05). This doubling of N2O emissions was linked to a relative reduction of 9 % in soil porosity (i.e., 0.05 cm3 cm−3) caused by applied compaction. This linkage to soil porosity was clearly evident in both croplands and pastures. Across the managed terrestrial ecosystems evaluated, the strongest relative effects of compaction on N2O emissions were found in forest and pasture soils. Overall, N2O emissions in forest soils showed a fivefold increase caused by compaction (P < 0.05; n = 11). This massive response in forest soils can be attributed to: i) their low N2O emission baseline; ii) their acidic pH, which intrinsically favors N2O emissions; iii) having some of the heaviest traffic loads found across our meta-analysis (e.g., 16 Mg); and iv) an increase in soil microporosity. Pasture soils also displayed substantial compaction effects on N2O emissions, with a threefold increase (P < 0.05; n = 25). This was explained in part by the elevated nitrogen input rates in pastures (e.g., 600–1000 kg N ha-1). Conversely, alleviation of soil compaction by implementing controlled traffic farming (CTF) in vegetable and grain croplands reduced N2O emissions consistently in all available pairwise comparisons (P < 0.05; n = 19). At the field scale, CTF greatly decreased N2O emissions by one-third compared with farmlands managed with conventional random traffic (4.48 versus 2.86 kg N2O-N ha-1). However, after reviewing the available literature, we witnessed a paucity of information about how long it takes for soils to self-alleviate from the detrimental effects of compaction on N2O emissions. Additionally, insights gained through meta-analysis revealed the interplay of soil compaction with underlying heavy textures, acidic pH, and reduced porosities, which collectively exacerbate N2O emissions. Nevertheless, these complex interactions operate differentially across contrasting land use options.

A meta-analysis of the impact of traffic-induced compaction on soil physical properties and grain yield

Soil compaction caused by wheel traffic is a major driver of soil degradation in modern agriculture and thus, a threat to agricultural sustainability. To improve the predictive capacity of compaction models and to support decision-making that implements site-specific practices for ameliorating soil compaction effects in modern agriculture, we need quantitative syntheses of the effect of soil compaction on soil physical properties and crop types. In this work, we used a meta-analytical approach to summarize results from 51 published articles on the impacts of soil compaction attributed to machinery axle load, wheel passes, compaction events and tire inflation pressure on soil bulk density (ρb), degree of compactness (DC), penetration resistance (PR), volume of water filled pores at field capacity (θFc), air permeability (ka) at field capacity, saturated hydraulic conductivity (ksat), and grain yield of corn (Zea mays L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and soybean (Glycine max L.). Results from this meta-analysis (MA) showed that compaction increased soil mechanical strength shown by increased soil ρb, DC and PR. However, an increase in soil strength was more pronounced in the medium- and coarse-textured soils, and mainly in the topsoil (0–30 cm depth). Penetration resistance for the non-compacted soil (control) treatment was 1.21 MPa for the coarse-textured, 1.11 MPa for the medium-textured and 0.93 MPa for the fine-textured soils. Soil compaction on average, increased PR by 99, 94 and by 41 percent in the medium-, coarse- and fine-textured soils. Compaction decreased hydraulic conductivity characterized by ka and ksat from the topsoil down to the subsoil (>40 cm depth), and grain yield of corn, wheat, barley, and soybean. Overall, compaction decreased grain yield on average by 6–34 percent. Findings of the MA suggest that soil hydraulic properties may be more sensitive indicators to reflect the impact of soil compaction on soil structure and pore system functions in the soil profile. Future efforts should place a greater emphasis on the publication of complete metadata that allows replication and accurate comparison of results across studies and on providing open access to original datasets that can be used to improve our understanding of the effect of traffic-induced compaction on soil functioning, including crop production.

Implantation and biomass of Avena sativa L., two methodologies of preparation, tillage soil and direct sowing

Autumn sowing of oats and other winter species is the alternative to balance the annual dry matter production in Uruguay, with fast forage availability in 60 to 70 days and high nutritional quality. The objective of this research was to evaluate the implantation, biomass production and effect of soil compaction, on the production of oats in two soil conditions, intensive tillage and direct sowing, with two doses of fertilizer, in rain-fed. The experimental design was randomized blocks with 20 repetitions of 50x10cm for implantation and 18 repetitions of 7x4m, for biomass production. The cultivar used was La Estanzuela 1095a. It was determined: implantation of crop, biomass production and the resistance of soil to the penetration. The germination in tillage soil (TS) and direct sowing (DS), showed 91.7 and 76.6% emergence, respectively. The forage production showed no significant differences between TS and DS. The statistical analysis of the green matter data showed a significant difference between the treatments for the control plots and 50 units of nitrogen. The penetration resistance for the 1 cm-2 cone showed significant differences at 15 cm depth, while for the 5 cm-2 cone the significant differences were at all depths, with DS being greater. The TS treatment showed lower resistance to penetration, better implantation and greater biomass production.

The effects of soil compaction and fertility on a threatened endemic palm species in a global conservation hotspot

Butia eriospatha (Mart. ex Drude) Becc. is a subtropical endemic palm tree that occurs in the Southern Brazilian Highlands. A vast area of its natural habitat has been lost by land-use changes, placing the species at high risk of extinction. Here, we investigated how environmental variables impact the structure of B. eriospatha populations. We randomly allocated 14,100 × 100 m plots, where all palms had the diameter at breast height (dbh) and the total height (th) measured. In the same plots, we collected data on edaphic, topographic, and land-use variables. The data were analysed by frequency histograms, factor analysis of mixed data, and regression trees. B. eriospatha’s size class frequencies tended towards a normal distribution, with few small individuals. We found that plots with flatter terrain had more compacted soils. The structure and biometrics traits of B. eriospatha’s populations were affected by the interaction between soil compaction and fertility. We conclude that sites with lower fertility and more compacted soils showed populations with lower abundance and basal area, and smaller individuals. Sustainable practices of soil management are required to prevent the species from becoming locally extinct.

A numerical study into effects of soil compaction and heat storage on thermal performance of a Horizontal Ground Heat Exchanger

The good capacity of the numerical simulations makes possible to bring some further responses on the backfill soil selection and its installation depth in the Horizontal Ground Heat Exchanger (HGHE). Therefore, a well-known backfill soil was considered to be used as substitutive material. The hydrothermal properties of the backfill material were estimated in laboratory and then injected in a numerical framework considering the atmosphere-soil-HGHE interaction. Numerical simulations were performed for a HGHE installed in the compacted backfill soil and the local natural soil. The simulation results showed that the compacted backfill soil improves by 8.5% the HGHE performance compared to local uncompacted soil. Two heat storage scenarios at three different installation depths were also investigated. The results showed that an inlet fluid temperature of 50 °C in summer increased highly the system performance by 13.7%–41.4%, while the improvement was less significant (0%–4.8%) for the ambient inlet temperature scenario. A deeper installation depth of HGHE increased also the system performance, the more energy could be stored and extracted.

Construction and Experimental Verification of Sloped Terrain Soil Pressure-Sinkage Model

The construction of a scientific and effective soil pressure-sinkage model under sloped terrain condition has important guiding significance for the investigation of the soil compaction effect. It is also important for the theoretical calculation of driving resistance and design optimization of the undercarriage structure of hillside metal-tracked tractors (HMTs). The classic Bekker’s pressure-sinkage model does not consider the influence of the soil water content, bulk density, slope angle, and other factors; therefore, it cannot be directly used to investigate the relationship between the soil compaction and its sinkage under sloped terrain conditions. To solve this problem, this study first verified that the soil water content and bulk density exert significant effects on the pressure–sinkage relationship under flat terrain condition. Secondly, a pressure-sinkage test was carried out using the quadratic rotation orthogonal combination design method, and the soil water content, density, and slope angle were considered. The pressure-sinkage curves of sloped terrain soils from Yangling and Yangxian in Shaanxi Province, and Huining and Jingning in Gansu Province were obtained. Then the pressure–sinkage parameters (sinkage exponent, cohesive modulus, and frictional modulus) were calculated using the weighted least-squares method. Thirdly, the mathematical relationship between the parameters and the soil water content, bulk density, and slope angle was obtained. Then Bekker’s model was modified to obtain the pressure–sinkage model of sloped terrain. Finally, the control variable method under slope angle of 10°, soil water content of 10%, and bulk density of 2 mg·m−3 were used to validate the model. The results revealed that the root-mean-square error between the calculated pressure value of the model and the measured value of the film pressure sensor was 1.614, 1.601, and 0.822, respectively. In the dynamic operation of a hillside tractor prototype, the calculated pressures between the supporting wheels were close to the measured values. It indicates that the modified soil pressure–sinkage model is more suitable for calculating the force at the bottom of the track between the supporting wheels. It can also provide an important theoretical basis for accurately calculating the pressure–sinkage parameters of sloped terrain soil. Additionally, this approach could provide theoretical and technical support for the rational arrangement of HMT undercarriages to reduce the soil sinkage and driving resistance.

Effect of Soil Compaction and Application of Lime and Gypsum on Soil Properties and Yield of Soybean

ABSTRACT Lime and gypsum application is one strategy for correcting soil acidity and improving soil fertility. However, soil compaction in no-till systems can influence these dynamics. This study aimed to assess the effect of lime and gypsum application under different soil compaction levels on soybean yield and soil chemical attributes. The application of lime and gypsum under artificial compaction levels and the movement of exchangeable calcium (Ca2+), magnesium (Mg2+), potassium (K+), and soil pH were monitored in the 0–0.05, 0.05–0.10, 0.10–0.20, and 0.20–0.40 m soil layer depths. Soybean grain yield was not influenced by the gypsum and lime applications and artificial compaction levels. In the 0.05–0.1, 0.1–0.2, and 0.2–0.4 m soil layers, the exclusive surface application of lime was effective in increasing the soil pH. Ca2+ and Mg2+ carbonates had low solubility and mobility in the soil; however, a rapid reaction to the surface over a relatively short period was observed. K+ concentration in the 0–0.05 m soil layer did not vary after the gypsum and lime applications. Therefore, the superficial application of lime is effective in acidity correction in no-till systems when the soil is not compacted.

English

Soil microbial biomass (SMB) is the main driving force in nutrient cycling and good indicator of soil productivity. A greenhouse experiment was designed to assess the effect of soil compaction, cropping system [sole maize, rotation 1 (inoculated soybean-maize), rotation 2 (un-inoculated soybean-maize) and intercrop 1(inoculated soybean-maize)and intercrop 2(un-inoculated soybean-maize)] and nitrogen fertilizeron soil microbial biomass C (SMB-C) and N (SMB-N) and their proportion to soil organic C and total N. SMB-C and SMB-N were higher in un-compacted than compacted soils with percent differences of 2.63 and 6.04% respectively. However, they were 19.32 and 36.36% lower in sole maize compared to rotation 1, 7.83 and 15.36% for rotation 2, 22.19 and 20.06% for intercrop 1 and 14.62 and 12.54% for intercrop 2. The results also showed that the application of 120 kg N ha-1 produced the highest soil microbial biomass as a percent of soil organic carbon, followed by 80 kg N ha-1, while the least value was obtained under zero application of nitrogen. Microbial biomass carbon and nitrogen as a percent of soil total nitrogen was significantly higher up to 80 kg N ha-1 before it decline at 120 kg N ha-1 suggesting better soil productivity improvement at 80 kg N ha-1 under the cropping systems with inoculated soybean. The findings indicate the need for inoculation in soybean-maize cropping systems to improve soil microbial biomass especially under less soil disturbances. Key words: Compaction, Brandyrhizobium Inoculation, Nitrogen fertilizer, microbial biomass, greenhouse.

Settlement of Footings on Compacted and Natural Collapsible Soils upon Loading and Soaking

Collapsible unsaturated soils experience large volumetric compressive deformations upon wetting. Soil collapse is a geotechnical problem that occurs in different regions of the world and profoundly impacts buildings and civil infrastructure constructed on this type of soil, with the associated impact on safety and economy. Compaction is a simple, relatively cheap, and yet effective soil improvement technique that could significantly reduce soil collapsibility. This paper combines laboratory tests, in-situ investigations, and numerical modeling to gain a better understanding of the effect of soil compaction on collapsible-soil settlements upon wetting under field conditions. The finite elements program CODE_BRIGHT was adopted for the numerical simulations of the field tests using model parameters that were previously obtained from independent laboratory experiments. The laboratory campaign comprised suction-controlled oedometer and triaxial tests of the natural and compacted soils considered in this study, as well as permeability and water retention experiments. The numerical simulations show that the proposed approach can model the behavior observed in the in-situ tests involving footing prototypes on collapsible soils subjected to soaking. These analyses also demonstrate that soil compaction is a viable technique to reduce collapsibility in order to meet predefined maximum allowable settlements. Additional analyses were carried out to extend the main findings to other soils and loading conditions. Based on stress-bulb concepts, a method is proposed to reduce settlements in collapsible soils for typical footing operational conditions.

Effects of turf, leaf litter, and soil compaction on emergence and establishment of invasive glossy buckthorn (Frangula alnus)

Perennial invasive plants can be controlled by damaging established vegetative individuals or by preventing establishment of new plants from seed. Less information is available about the latter. We examined how seedling establishment of glossy buckthorn (Frangula alnus), a non-native shrub that invades forests in eastern North America, is affected by four soil surface treatments – grass-dominated turf, oak leaf litter, pine leaf litter, soil compaction – relative to an untreated control (tilled soil). Data on seedling emergence, survival, growth, and reproduction were collected from 1.5 m2 plots (six per treatment) over two years at the Kingman Research Farm, Madbury, NH, USA. Overall, buckthorn success from seed was inhibited by grass turf and facilitated by oak litter, while pine litter effects were complex and soil compaction had no effect. Specifically, relative to control, the turf treatment reduced buckthorn seedling emergence (year 2 only), increased mortality over two years, reduced density of living buckthorn, and prevented fruiting. Oak litter resulted in greater buckthorn seedling height relative to control, while pine litter, although reducing seedling emergence (year 1 only), increased both seedling height and the proportion of plants fruiting in year 2. Across all treatments and control, buckthorn seedling emergence was greatest in June, declining thereafter. Of the four treatments, only grass turf offered some promise of resisting invasion. The mechanism of resistance by turf is not known, but likely involves either more intense competition or higher levels of herbivory associated with turf. The mechanism, as well as the logistics and cost of turf establishment in logged areas, require further exploration.

Effects of Soil Compaction in the Fight against Unpaved Roads Degradation Due to Erosion Caused by Heavy Rain: Proposition of a Specific CBR Evaluation Model

Unpailt roads are generally subject to erosion, when they need to be bitumen, civil engineers need to know the geotechnical capabilities of the soil layers to be used as support, among these capabilities, for example, soil characteristics to withstand erosion. CBR has often been used to classify these soils according to their compaction. In this article, we propose a correlation between CBR and eroded soil mass through a simulator. Indeed, in this article we show that using a simulator, soils can be classified according to their ability to withstand water erosion, whether internal or external. Indeed it is shown that the mass of eroded soil is related to the compaction capacity of the soil just as the CBR also has. We study the effects and influence of soil compaction on the ability of an unpaved road to resist erosion caused by falling raindrops. To do this, lateritic soil is submitted to different compaction pressures. The compacted soil is then submitted to CBR test and rain fall through a mini rain simulator. Correlations between eroded soil masse and compaction pressure as well as CBR are derived. The study shows that the compaction reduces the erodibility and increases the bearing capacity of soil. The formula obtained is significant because we have a new way of evaluating soils in the laboratory.

Soil compaction and cover with black oat on soybean grain yield in lowland under no-tillage system

ABSTRACT: Brazil is the largest exporter and second largest producer of soybean grains. Most of this production is from plants grown under no-tillage system (NT). This research evaluated the effect of soil compaction, and different amounts of black oat residues on the soil surface on soybean growth and grain yield in lowland under NT. The experiment was conducted in a completely randomized design with seven treatments and four replications, in the 2016/2017 and 2017/2018 crop seasons. The treatments consisted of: 1) winter fallow without soil compaction (WF); 2) winter fallow with soil compaction (WF-C); 3) black oats and complete removal of surface residues, with soil compaction (0R-C); 4) black oats and removal half of surface residues, with soil compaction (0.5R-C); 5) black oats without surface residue removal, with soil compaction (1R-C); 6) black oats without surface residue removal, plus the residues from treatment 3, with soil compaction (2R-C); 7) black oats without surface residue removal, without soil compaction (1R). When the soybean plants were at the phenological stage R2, they were evaluated nodule, root and shoot dry matter, nitrogen contents, plant height, and grain yield. The soil physical properties were evaluated in the 0.0-0.05, 0.10-0.15 and 0.20-0.25 m layers. The soybean aerial dry matter is &gt; 38% in non-compacted soil in year with soil water excess, regardless of the amount of surface oat straw. In year with small water deficit, soil with more surface oat straw produced &gt; 5% shoot dry matter and &gt; 4% of soybean grain, regardless of compaction. The plant growth and grain yield soybean in lowland varied according to the water conditions, and were affected by soil compaction and amounts of black oats residues on soil surface.

Experimental Study and Measures on Engineering Characteristics of Diatomite Subgrade in Shengzhou

This paper takes the newly built railway passing through the diatom land area of Shengzhou and Xinchang in Zhejiang Province as an example. And based on the field test of soil samples, this paper pointed out that due to low natural density, large void ratio, high water content, dry shrinkage and wet expansion, relative deformation and strength, The diatomite are not suitable to be directly used as building foundation. Based on the static load of single pile, bearing capacity of composite foundation and in-situ vibration test of foundation bed, it proposed that CFG pile, plain concrete pile and reinforced concrete pile are suitable for diatomite foundation reinforcement. While screw pile has insufficient bearing capacity, due to soil compaction effect and poor pile forming effect of high pressure jet grouting pile. CFG and plain concrete pile composite foundation can meet the requirements of diatomite subgrade deformation, and plain concrete pile is much better. The raft structure has better integrity. The capillary waterproof and drainage board can significantly improve the waterproof and drainage effect, and reduce the adverse effect of dynamic load on diatom soil foundation. Based on the slope rainfall test, it is proposed that diatomite natural slope is easy to form network cracks and induce shallow landslide under the action of dry wet cycle. In addition, the effect of gentle slope and skeleton on Diatomite slope is better.

Effects of Shading and Soil Compaction on the Growth, Leaf Area and Biomass Allocation of Tomatoes (Lycopersicon esculentum)

Plants are often exposed to stressors such as shading and soil compaction, influencing their morphology and physiology. This study aimed to determine the effects of shading (e.g. using black, white, and transparent cloths) and disturbance on the growth, leaf area, and biomass allocation of plants using tomatoes (Lycopersicon esculentum). The establishment of the study area and gathering of field data were conducted for one month at Davao Oriental State College of Science and Technology (DOSCST), Mati City, Davao Oriental. In the shading experiment, the leaf weight ratio (LWR) of the plants was revealed to be directly proportional to their exposure to sunlight. A similar trend was observed on the specific leaf area (SLA) and leaf area ratio (LAR) values, with the SLA and LAR values higher on the plots with the most shading and decreasing with increasing exposure to sunlight. In the disturbance experiment, the LWR and SLA were observed to be inversely proportional to the intensity of disturbance with higher values reported on the undisturbed plot. A general pattern was observed in terms of biomass allocation in the plant parts; the stems have the bulk of the weight, followed by the leaves while the roots have the least weight. In the shading experiment, the highest biomass was observed on the white fabric-covered plot and the least on the black fabric-covered plot. In the disturbance experiment, the undisturbed plot was observed to have higher biomass than the disturbed plot. These have implications in terms of crop cultivation.

Subsoil compaction effect on spatio-temporal root growth, reuse of biopores and crop yield of spring barley

Subsoil compaction in arable farming caused by increasingly heavy machinery results in increased subsoil strength and reduced aeration and water flow. This can restrict root growth and reduce crop yield. To mitigate these effects of subsoil compaction, we included a deep-rooted catch crop of fodder radish (Raphanus sativus var. oleifera) in a rotation of spring barley (Hordeum vulgare). The objective was to determine the effect of subsoil compaction on root growth and grain yield of barley, and to investigate the creation and use of biopores for subsequent root growth. Studies were carried out in 2013–2016 in a soil compaction experiment established in 2010 on a sandy loam. The soil had for four consecutive years (2010–2013) been compacted with multi-passes in an 8 Mg wheel load treatment (M8) or had not been compacted (Control). Spring barley was grown every year and fodder radish was grown as a catch crop from harvest to winter in 2013–2016. Penetration resistance to 90 cm depth was measured in 2015 at a soil water content near field capacity. Root growth and biopore reuse were investigated using horizontal minirhizotrons installed at 30, 50 and 70 cm depth from 2013–2016. Spring barley grain yield was recorded annually. We found that M8 caused critical subsoil compaction with penetration resistance peaking at 3.5 MPa in the upper subsoil (30−40 cm depth). Subsoil compaction reduced root growth by c. 50 % at 30 cm depth and barley yields by 6–8 % compared to the Control in three years after cessation of the compaction treatment. The number of biopores that were reused were higher for fodder radish than for spring barley, 4.1 % and 3.1 %, respectively, but did not differ between compaction treatments. Our study displayed a marked, negative residual effect of soil compaction on above- and belowground crop growth. There was no tendency towards a recovery within the years studied (1–3 years after compaction). Severe subsoil compaction is a widespread problem and therefore we call for more studies on the spatio-temporal dynamics of the creation and subsequent use of biopores for root growth as these are essential for the recovery of compacted subsoils.

Effect of Soil Compaction and Palm Oil Application on Soil Infiltration Rate

AbstractWater-saving technologies have been gaining interest as a way of saving water while minimizing crop production losses. This study aims to introduce a new technique for reducing the vertical...

Compaction and cover effects on runoff and erosion in post‐fire salvage logged areas in the Valley Fire, California

AbstractRunoff and erosion processes can increase after wildfire and post‐fire salvage logging, but little is known about the specific effects of soil compaction and surface cover after post‐fire salvage logging activities on these processes. We carried out rainfall simulations after a high‐severity wildfire and post‐fire salvage logging to assess the effect of compaction (uncompacted or compacted by skid traffic during post‐fire salvage logging) and surface cover (bare or covered with logging slash). Runoff after 71 mm of rainfall across two 30‐min simulations was similar for the bare plots regardless of the compaction status (mean 33 mm). In comparison, runoff in the slash‐covered plots averaged only 22 mm. Rainsplash in the downslope direction averaged 30 g for the bare plots across compaction levels and decreased significantly by 70% on the slash‐covered plots. Sediment yield totalled 460 and 818 g m−2 for the uncompacted and compacted bare plots, respectively, and slash significantly reduced these amounts by an average rate of 71%. Our results showed that soil erosion was still high two years after the high severity burning and the effect of soil compaction nearly doubled soil erosion via nonsignificant increases in runoff and sediment concentration. Antecedent soil moisture (dry or wet) was the dominant factor controlling runoff, while surface cover was the dominant factor for rainsplash and sediment yield. Saturated hydraulic conductivity and interrill erodibility calculated from these rainfall simulations confirmed previous laboratory research and will support hydrologic and erosion modelling efforts related to wildfire and post‐fire salvage logging. Covering the soil with slash mitigated runoff and significantly reduced soil erosion, demonstrating the potential of this practise to reduce sediment yield and soil degradation from burned and logged areas.

Assessing the impact of agricultural field traffic on corn grain yield using remote sensing and machine learning

With the increase in the physical size of agricultural field machinery, producers can experience negative effects of machinery-induced soil compaction on soil health and crop productivity. Traditionally, the impact of compaction from machinery traffic on crop yield has been examined either by hand harvesting of crops or by using yield maps generated using yield monitors mounted on combines at the time of harvest. While a hand harvesting approach is time consuming, laborious and subjective, yield maps generated from yield monitors are too coarse in resolution to truly assess the yield differences between individual crop rows. Remote sensing technology offers a cost- and time-effective approach to generate high-resolution yield maps that can be used to assess crop yields of individual rows or areas within a row and, thus, the impacts of field traffic on crop yield. The objectives of this study were to: (1) develop a framework to predict crop grain yield at both the centimeter scale and individual row level by integrating remote sensing and field collected data, and (2) use the predicted yield map to assess the impact of field traffic during planting on corn grain yield. Field experiments were conducted in three corn fields, each in 2016, 2017, and 2018, at the Molly Caren Agricultural Center, London, Ohio, to evaluate yield impact of field traffic at planting. Data collected included corn grain yield based on yield monitors and hand-harvesting, and aerial (i.e., visible and multispectral) imagery collected during the corn growing season. Corn grain yield was predicted using six machine learning algorithms (i.e., linear regression, random forest regression, support vector machine, stochastic gradient boosting model, neural network, and cubist). The results from the high-resolution yield maps were consistent with hand-harvest and yield-monitor data. Models using a cubist algorithm predicted corn grain yield with R2 of 0.76, 0.61 and 0.88 for fields F11, F8A and F7, respectively. Based on high-resolution corn grain yield maps, yield differences between rows that were most impacted by tires (i.e., pinch rows) and least impacted (i.e., non-pinch rows) at the time of planting were less than 0.1 t ha−1 and not significant. Corn grain yield varied based on the soil landscape in the field, with 39–75 % of the field showing higher corn grain yield in non-pinch rows than pinch rows. The developed framework could also be applied to assess the effect of other field management practices on crop yield with higher accuracy and resolution.

Calculation of influence range of impact holing on the adjacent railway

In order to solve the impact of actual construction projects on the existing surrounding environment, the impact and vibration of the impact on the existing railway subgrade stability caused by the construction of the bridge foundation are analyzed. Based on the actual case of the construction project of No. 37 main pier across the Jiaoji Railway Main Bridge at Binlai expressway, the influence of the impact holing on the adjacent railway is analyzed. The influence range of the construction vibration is based on the Chinese Seismic Intensity Scale (GB/T 17742-2008) and Safety Regulations for Blasting (GB6722-2014), and taking the maximum velocity allowable value as criterion, the minimum safety range of impact drilling is obtained. Using the theory of small hole expansion to calculate the influence of the effect of soil compaction, the minimum allowable value of safe distance for the Construction technology of impact forming hole is considered 6.5m; in addition, based on the numerical simulation of nonlinear time history analysis, a reasonable exciting force parameter is given for practical engineering. The influence of impact amplitude A and impact frequency f on construction safety distance is analyzed. The results show that: The minimum safety distance of impact drilling is linear with the increase of impact amplitude A. When the impact frequency f is greater than 10Hz, the minimum safety distance tends to a fixed value as f increases. The results of this study guide the actual construction of the field, it guarantees the normal traffic of the Jiaoji Railway and provides a theoretical support for similar projects.

Quality of Scots pine, European beech and pedunculate oak grown from sowing on soil with different compaction levels

Abstract In this study, we explore the effect of soil compaction on the growth of seedlings of Scots pine Pinus sylvestris L., European beech Fagus sylvatica L. and pedunculate oak Quercus robur L. On the experimental plots, ground contact pressures ranging from 0 to 250 kPa was applied on the soil. The applied pressure resulted in an increase in soil compaction between 1.02 to 1.19 g cm–3, which reflected pressures exerted by the undercarriage of vehicles used in logging. We then measured the seedlings as well as the dry weight of the roots and the above-ground parts. Using this data, we calculated the following quality indicators for each seedling: SQ – sturdiness quotient, S/R – shoot to root dry mass, DQI – Dickson quality index. For pedunculate oak, the SQ value significantly improved with increasing soil compaction, whereas no differences in the other two indicators were observed. In case of the European beech, the best value of SQ and DQI were observed at a soil density of 1.11 g cm–3, whilst no significant difference for the S/R coefficient could be found. Completely different results were obtained for Scots pine. The most favorable growth was observed when no pressure was applied. However, the SQ and S/R ratios even exceeded the values commonly considered acceptable. Our results therefore indicate that the values of seedling quality indicators are indeed influenced by soil compaction. At a soil compaction of 1.11 g cm–3, the share of seedlings with the SQ value below the critical level was the highest, but a similar relationship could not be confirmed for the other indicators. The response of the seedlings to compaction is likely to be species specific.