Risk Of Soil Compaction Research Articles

Tire rating based on soil compaction capacity

Compaction Capacity (CC) rating of tires presents a unique numerical CC index evaluating soil compaction risk of loaded tires. The CC rating presented here is a final product of experimental research and analysis of relations between external load and soil compaction, avoiding the intermediary role of soil stress. The research included laboratory model measurements of soil compaction by rigid round pressure plates in a cylindrical soil container. Equation for the CC index reads: CC=1000 [(soil dry density/1420)−1], where the number 1420 indicates the dry density of loam in kg/m3, critical for plant growth. The CC rating takes into account the area of tire−ground contact patch and tire load, which depends on inflation pressure. If the average dry density is 10% higher than the critical dry density, the CC index equals 100. This is considered as a practical limit to ecological tire operation on cultivated crop-producing land. Agricultural tires with mean contact pressures less than 70kPa have zero CC index. Their qualities are classified by Low Compaction Capacity (LCC) index based on 1290kg/m3 soil dry density. Both the CC and LCC indices do not distinguish between towed and driven wheels. The tables in this paper show how these simple indices can complement load data published by tire manufacturers.

Application of Bayesian Belief Networks to quantify and map areas at risk to soil threats: Using soil compaction as an example

The assessment of areas at risk from various soil threats is a key task within the proposed EU Soil Framework Directive. Such assessment is, however, hampered by the complex nature of the soil threats, which result from the sometimes poorly understood interaction of various soil physical properties, climatic factors and land management practices. Methodologies for risk assessment of soil threats are needed to protect the soil quality for future generations and to target resources to the areas at greatest risk. We present here a generic risk framework for the development of Bayesian Belief Networks (BBNs) to estimate the risk from soil threats. The generic BBN structure follows a standard risk assessment approach, where the risk is quantified by combining assessments of vulnerability and exposure. The soil's vulnerability to a given threat is determined from inherent soil and site characteristics as well as from climatic factors influencing soil characteristics, while the exposure estimate is based on an evaluation of the stresses inflicted by land management and climate. The generic framework is demonstrated by taking soil compaction as an example. Soil compaction is a major threat to soil function particularly in highly managed agricultural systems and is known to have many adverse effects on farming systems including decreased crop yield and soil productivity, increased management costs, increased emissions of greenhouse gases, and decreased water infiltration into the soil leading to accelerated run-off and risk of soil erosion. Existing modelling approaches to predict soil compaction risk either require data on soil mechanical behaviour that are difficult and expensive to collect, or are expert-based systems that are highly subjective and sometimes cannot accommodate the myriad of processes underlying compaction risk. Using the generic framework, a detailed BBN for assessing the risk of soil compaction is developed. The BBN allows for combining available data from standard soil surveys and land use databases with qualitative expert knowledge and explicitly accounts for uncertainties in the assessment of the risk. The BBN is applied to identify the distribution of the compaction risk across Scotland using data from the National Soils Inventory of Scotland.

Evaluation of soil compaction by modeling field vehicle traffic with SoilFlex during sugarcane harvest

Sugarcane harvest in Brazil involves infield traffic of trailers, haulout trucks and tractors, increasing the risk of soil compaction. Pseudo-analytic models have been used for analyzing soil compaction due to traffic as well as a tool to prevent it. The objective of this paper was to analyze the compaction process of an Ultisols in the costal table of Pernambuco, Brazil, subjected to vehicle traffic during sugarcane harvest. The pseudo-analytical model SoilFlex was used for modeling bulk density and soil moisture scenarios based on undisturbed soil samples taken at 0–0.1, 0.1–0.2, 0.2–0.3 and 0.3–0.4m depth in a 120m×120m area. Five bulk density scenarios, each one with four soil moisture conditions, were evaluated after passing vehicles during harvest: a loaded haulout truck, a loaded trailer hauled by a tractor and a loaded haulout truck hauling a loaded trailer. Soil vertical and pre-compression stresses showed that the haulout truck, as well as the trailer hauled by tractor, cause soil compaction beyond 0.2m depth when the initial bulk density were 1.3, 1.4 and 1.5gcm−3.

Reducing the risk of soil compaction by applying ‘Jordværn Online’® when performing slurry distribution

Through a case study, it is shown that the potential of applying JORDVÆRN Online® as a decision-making tool aimed at supporting sustainable in-field traffic provided the farmer with the potential to improve and maintain the soil as a continued growth medium for the future agri-food production. The combination of CTF and optimal selected tyre configurations provides the farmer with the potential of cropping agricultural land without creating permanent soil compaction. Additional, the case study indicates an urgent need for the development of alternative systems for in-field traffic in wet conditions, e.g. multiple-axle trailers with real low-inflation tyres.

Procedures of soil farming allowing reduction of compaction

Evaluation of new technologies using guidance systems is very important and can help producers with choosing the right equipment for their applications. Without using satellite navigation during field operations, there is a tendency for passes to overlap. That results in waste of fuel and pesticides, longer working times and also environmental damage. When utilising satellite guidance for field operations, there is a close connection with controlled traffic farming (CTF) as well. CTF is currently a quite quickly developing farming system based on fixed layout of machinery passes across a field. Tracks precisely set out for a machine’s tyres in the field could be a tool for minimising soil compaction risk which is another threat to the environment. The purpose of this paper was to evaluate the accuracy of currently available guidance systems for agricultural machines. Real pass-to-pass errors (omissions and overlaps) in a field were measured. Consequently, comparison between observed guidance systems was made regarding final working accuracy. Further, intensity of machinery passes, percentage of wheeled area and repeated passes in fields were monitored. These measurements were made in fields under real operating conditions using a conventional tillage system with ploughing and also a conservation tillage system, both systems with randomly organized traffic. Finally, the same parameters were monitored in fields where fixed machinery tracks were used for all operations and passes but only under a conservation tillage system. Pass-to-pass accuracy was measured for the evaluation of different guidance systems. Size of missed areas or overlaps was evaluated statistically. Concerning intensity of machinery passes and total field area affected by machinery passes, the following facts were found out. The experiments with randomized traffic showed a significant difference of the parameters mentioned above between a conventional tillage system with ploughing and a conservation tillage system. Wheeled area was 86 and 64%, respectively which proves benefits of conservation tillage. The experiments with a fixed track system showed that the total run-over area by machinery tyres decreased even more (up to 31%) in comparison to randomized traffic in a field (only fields under conservation tillage system were monitored and evaluated). The following statements based on our results can be made. The navigation and therefore possibility for better accuracy of machinery passes in fields together with permanent machinery tracks utilization could help with soil condition improvement and also energy savings which would result from that. The CTF system will help with further development of a system for soil compaction protection which is currently a real necessity.

Progress in tire rating based on soil compaction potential

The general trend in soil protection is to reduce the detrimental soil compaction by loaded wheels of power and transport equipment. This paper reports on the progress in research of soil compaction risk assessment by means of Compaction Capacity (CC) tire rating originally introduced as compaction number (CN) rating [Grečenko A. Tire load rating to reduce soil compaction. J Terramech 2003;40:97–115]. The CC rating evaluates soil dry density along a vertical column 20–50 cm below the ground surface. The unique feature of the CC approach is that it converts laboratory compaction measurements directly to soil compaction profiles under evaluated tires without touching the stresses in the ground. The laboratory soil compaction is done with round pressure plate and similarly the tire contact area is represented by a virtual plate loaded by the same mean contact pressure. This paper describes laboratory testing procedures with fundamentals of data conversion and gives examples of CC rating application.

Q value for calculation of pressure propagation in arable soils taking topsoil stability into account

Reliable recommendations for practice are required, to enable farmers themselves to decide whether or not it is acceptable to drive over the soil under the prevailing conditions. To this end, the pressure propagation has to be calculated by means of easily recorded parameters. The TASC program (Tyres/Track And Soil Compaction) makes a contribution to this. The risk of soil compaction may be evaluated with reference to six parameters (tyre size, wheel load, tyre inflation pressure, topsoil stability, soil type and maximum tillage depth). The program uses these parameters to evaluate the soil stress caused by tyres and tracks. The aim of the study is on the basis of field measurements to derive a regression equation for calculation of the q value (as a measurement of soil hardness when calculating the pressure propagation in the soil) as a function of the penetration resistance. The topsoil stability can then be taken into account when calculating the compressive stress. Locations ranging from high (ley on dry clay soil) to very low soil stability (shortly after ploughing) were selected for the purpose of the study. Soil pressure measurements were made at plough pan level at a total of nine sites (cropland and pasture) with light to heavy soils. Different machine weights were used, producing wheel loads varying from the empty slurry tanker (wheel load 1432 daN) to the 6-row sugar beet harvester (wheel load 10,678 daN). The q value is a measure of topsoil stability (penetration resistance). The q value is determined by the compressive stress at a particular depth, by the depth itself, by the contact area and by the wheel load. The so-called equivalent contact pressure can be recalculated on the basis of the compressive stress values measured at a depth of 20 cm. The ratio of the equivalent contact area pressure to the measured contact area pressure (wheel load/measured contact area) gives the q value. This value increases as the soil stability decreases. For the purpose of the regression calculation a logarithmic function was derived for mineral soils from the upper quartiles on the one hand and from the medians of the q value and the medians of the penetration resistance on the other. The coefficient of determination is 0.71. The function applies to mineral soils. First measurements on organic soils indicate that mineral and organic soils react differently to pressure propagation. No direct correlation was found here between penetration resistance and soil moisture.

A Comparison of Side-dressed Liquid Hog Manure to Urea Ammonium Nitrate in Corn

Liquid hog manure is frequently spring-applied prior to corn planting, but concern regarding compaction, planting delays, and nitrogen losses have increased corn producer interest in side dressing. The objective of this study was to compare available nitrogen in side-dressed liquid hog manure versus 28% urea ammonium nitrate (UAN) in terms of fertilizer nitrogen equivalent, yield response, grain protein, soil compaction, and end of season soil nitrates. Field experiments were conducted at three sites in southwestern Ontario from 2003 to 2005. Three rates of liquid hog manure (zero, low, and high) and five rates of UAN (0, 53, 106, 159, 220 lb of N per acre) were applied at side-dress timing in corn. Available nitrogen in side-dress applications of liquid hog manure was equally effective as UAN in supplying corn nitrogen requirements based on comparisons of yield and grain protein concentration. Drier conditions at side-dress timing reduced soil compaction risks and yield reductions arising from possible root pruning were not observed. Side-dressed liquid hog manure should be applied at rates of available nitrogen that correspond to crop nitrogen demand, since like UAN, excess applied nitrogen will be susceptible to late season losses.

Modelling experts’ judgments on soil compaction to derive decision rules for soil protection—A case study from Switzerland

Soil compaction has been recognized as a serious environmental problem, and therefore its prevention is incorporated in the soil protection legislations of many countries. Implementation of these legislations needs decision rules and thresholds to assess the state and risk of soil compaction. The following contribution presents the results of a Delphi survey among Swiss soil experts eliciting their personal experience in judging soil compaction in order to derive their implicit decision rules and thresholds. The experts were asked in the first turn to mention the three most important physical soil parameters they use to judge the state of and the susceptibility to compaction. In the second and third turn, they had to group 21 data records with real measurements of soil physical parameters into five different classes of severity for the state of and susceptibility to compaction. We analysed the experts’ answers with descriptive statistics and a cluster analysis. Further, we developed a fuzzy membership model to classify the soil data after the experts’ groupings. The model was validated with a Jack–Knife estimation for each data record. The Delphi survey revealed a high convergence of the experts’ answers. Although, in the first turn, the experts stated qualitative parameters like water regime and soil structure to be very important for judging soil compaction, in the second and third turn they mentioned only quantitative parameters to be crucial for their groupings of the data records. The decisive parameters to judge the state of compaction were coarse pore content followed by bulk density and precompression stress. Conversely, for judging the susceptibility to compaction precompression stress was stated as crucial parameter, followed by bulk density, coarse pore content and clay content. We observed that the experts allowed for different soil parameters simultaneously. We particularly assume that they took the clay content into account while judging the parameter of bulk density. The implicit thresholds of the experts were derived from the mean values and the ranges in the different classes of the state of and susceptibility to compaction. The critical limits correspond to indications in the literature. The experts defined soils with less than 7% coarse pore content and more than 1.7 packing density (a composite parameter of bulk density and clay content) as compacted. Soils with less than 65 kPa precompression stress and less than 1.7 packing density were considered very susceptible to compaction. While the statistical cluster analysis could not model the experts’ groupings in a satisfactory way, the fuzzy membership model was successful in 18 cases (out of 21) for both, the state of and susceptibility to compaction. The Jack–Knife estimation was successful in 11 cases for the state of compaction and in 12 cases for the susceptibility to compaction. The number of available samples was too small for a better Jack–Knife prediction. Although this model is still a prototype, it allows more for uncertainties of the experts’ decisions than thresholds from descriptive statistics, and may therefore be a more traceable tool to support the execution of the soil protection legislations.

Soil Failure Patterns and Load–sinkage Relationships under Interacting Shallow Footing and Wheel Arrangements

This study explores possible methods, based upon generating interactions between footing/wheel arrangements, for supporting a greater proportion of surface applied loads in the soil surface layers, rather than at depth. Such a change would reduce the risk of deep soil compaction occurring under high machinery loadings. In this work, shallow footings were used to simulate wheel arrangements. Dual and triple footing combinations were examined at different spacings and in different relative positions. This was to determine the effect of interactions within the soil failure zones beneath the footings, on the nature of soil deformation, interaction behaviour and the load–sinkage relationships. The mode of interaction was very dependent upon the spacing between the footings. Three interaction modes were identified and the load–sinkage relationships indicated that, with interaction, higher loads could be supported in the surface layers at given sinkages. A mathematical model, based upon Meyerhof's bearing capacity theory for shallow footings, was developed to predict the likely interaction modes and the additional forces that could be generated as a result of the footing interactions at different spacings. The model showed an acceptable level of agreement with the experimental data for a range of multiple footing sizes and spacings.

Cumulative effects of cropping systems on the structure of the tilled layer in northern France

A field experiment was initiated in 1989 in northern France to evaluate the cumulative effects of cropping systems on the structure of the tilled layer of a loamy soil. Three cropping systems involving different crop rotations and cultivations (early or late sowing, early or late harvesting) were compared. The soil structure was evaluated after each winter wheat sowing by a morphological analysis of the ploughed layer. We determined the proportion of highly compacted zones, i.e. the zones with a massive structure and no visible macropores in the soil profile. These zones, defined as Δ zones, result from severe anthropogenic compaction. The creation of Δ zones depended largely on the soil moisture at the time of field operations and the characteristics of the machinery used. Maximum compaction occurred during harvesting in wet conditions because of high axle loads. In contrast, little compaction was produced by seedbed preparation, which involved lower axle loads and wide tyres. Consequently, changes in soil structure depended to a large extent on the cropping system. However, the proportion of Δ areas was not stable, but fluctuated greatly from one year to the next. Δ zones could quickly disappear from the ploughed layer. We, therefore, detected no irreversible effects on the structure of the ploughed layer, even for the cropping system that produced the highest annual risk of soil compaction. The combined effects of tillage and climate led to fewer compacted zones in the surface layer. Because this layer was mixed with deeper layers during soil inversion at the next ploughing, this contributed to fewer Δ zones in the whole layer. The loss of Δ zones over the whole cultivated layer could not be explained by this effect alone and the reduction in soil compaction was probably due to the combined effects of loosening by mouldboard ploughing and climatic and soil fauna activities in the ploughed layer below the seedbed. The initial soil structure had a major effect on seedbed fragmentation. When preparing seedbeds in the autumn, the proportion of remaining clods depended greatly on the initial state of the ploughed layer even when using a power rotary harrow. In spring, the number of remaining clods was still dependent on the initial compaction, but they were fewer and no differences were observed between rotary and combination harrows.

Early sowing — a system for reduced seedbed preparation in Sweden

Conventional seedbed preparation for spring sown crops in Sweden includes 3–4 harrowings followed by sowing, but there is a great interest among farmers to reduce this tillage. Since the soil is normally at field capacity after winter, the conventional system implies a major risk of soil compaction and the farmer has to wait for the soil to dry before seedbed preparation can be started. A new technique that has been made possible by new types of seed drills and improved tyre equipment is early sowing of spring cereals without harrowing. It was tested in 74 field experiments in Sweden during 1992–1996, on soils with clay contents ranging from 6 to 57% (typically Eutric or Gleyic Cambisols). On an average, early sowing increased yield by 1% compared with that of conventional sowing. When early sowing was made more than 30 days before conventional sowing it increased yield by an average of 11%. There was no clear relation between yield response to early sowing and soil type. In four long-term experiments, there were no significant differences in bulk density or in saturated hydraulic conductivity between early and conventional sowing. As an average for all experiments, number of emerged plants was 6% lower for early than that for conventional sowing, but this factor did not seem to be decisive for crop yield. In an experiment, when barley ( Hordeum vulgare, L.) was grown after barley, there was a higher occurrence of leaf scald ( Rhyncosporium secalis (Sacc.) Shoemaker) and net blotch ( Dreschlera teres (Oudem) J.J. Davies) in early sown treatments, however, when all results are considered, the risk of increased plant pests due to early sowing seems small. In total, early sowing of spring cereals without harrowing may be beneficial to farmers since it reduces the cost of tillage and increases crop yield potential by lengthening the growing period.

Effect of trampling on the soils of the St James Walkway, New Zealand

Abstract. The influence of trampling on the soils of the St James Walkway was studied during 1985 by comparing ‘on’‐ and off‐track sites. Trampling increased the average soil bulk density by 0.3 g/cm3 at 0–5 cm depth and by 0.1 g/cm3 at 10–15 cm depth. Trampling increased the average soil shear strength by 11 kPa at 0–5 cm depth and by 6 kPa at 5–10 cm depth. All mineral soils were compacted to some extent by trampling. The podzolized high country yellow‐brown earths (Dystrochrepts) were the most affected because their organic topsoil was truncated. Their exposed subsoil was however more resistant to further damage than their topsoil. Organic soils (Medihemists) were not compacted but their very low shear strength and high moisture content make them unsuitable for tracks. Untrampled soil bulk density and soil stone content were negatively correlated with the change in bulk density by trampling, and could be used to predict the risk of soil compaction by trampling.

Computed reconstruction of field traffic patterns

The relationship between the degree of mechanization and the risk of soil compaction on arable farmland was studied, assuming soil conditions did not vary between mechanization systems. An inventory of machine characteristics and all field operations needed to grow the various crops was made on 27 arable farms in The Netherlands. The data obtained were processed so that crop-specific field rut patterns could be reconstructed. An indication of the number of wheel passes, together with information on tyre inflation pressure, wheel load and the soil compaction risk factor, was included. The wheeled area varies with crop type and farm size, owing to differences in the mechanization. Traffic intensity, or the number of times total coverage of the arable field with ruts occurs, varies between 5.4 ha ha −1 year −1 for a potato crop (farm sizes < 35 ha) and 2.2 ha ha −1 year −1 for winter wheat (farm sizes between 55 and 80 ha). Considering the average crop rotation occurring on the farms, traffic intensity decreased from 3.9 ha ha −1 year −1 (farm sizes < 35 ha) to 3.2 ha ha −1 year −1 (farms > 80 ha). The compaction risk factor tends to increase with growing farm sizes. From 80 ha onwards, however, the factor remains constant mainly owing to lower traffic intensity and maximum sizes of tyres, tyre inflation pressure and wheel load. Compaction measurements in normal arable farming practice give way to the assumption that penetration resistance is corrected with farm size, and thus with the degree of mechanization.

Satellite telescope being used by moonwatch groups

Sugarcane harvest in Brazil involves infield traffic of trailers, haulout trucks and tractors, increasing the risk of soil compaction. Pseudo-analytic models have been used for analyzing soil compaction due to traffic as well as a tool to prevent it. The objective of this paper was to analyze the compaction process of an Ultisols in the costal table of Pernambuco, Brazil, subjected to vehicle traffic during sugarcane harvest. The pseudo-analytical model SoilFlex was used for modeling bulk density and soil moisture scenarios based on undisturbed soil samples taken at 0–0.1, 0.1–0.2, 0.2–0.3 and 0.3–0.4 m depth in a 120 m × 120 m area. Five bulk density scenarios, each one with four soil moisture conditions, were evaluated after passing vehicles during harvest: a loaded haulout truck, a loaded trailer hauled by a tractor and a loaded haulout truck hauling a loaded trailer. Soil vertical and pre-compression stresses showed that the haulout truck, as well as the trailer hauled by tractor, cause soil compaction beyond 0.2 m depth when the initial bulk density were 1.3, 1.4 and 1.5 g cm−3.