Browsing by Author "Godwin, R. J."
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Item Open Access Agricultural tractor powertrains: Fundamental characteristics and opportunities for intelligent control(Cranfield University, 2005-07-08) Sayer, David; Scarlett, A. J.; Godwin, R. J.The use of microprocessor-based control systems on agricultural tractors has eased operator burden by allowing changes to tractor and implement settings to be made with little physical effort. However, maintaining the optimum tractor-implement settings whilst encountering the variable nature of agricultural conditions still requires a high level of operator skill, partly due to the need to adjust individual sub-system controllers. CAN-bus communication between electronically controlled vehicle sub. systems provided a new opportunity to enhance vehicle powertrain operation, by intelligently integrating control of the sub-systems. The aim of the project was to develop ways to improve the operational characteristics of a tractor powertrain, by investigating system behaviour, and identifying opportunities for intelligent control. Market research was undertaken which highlighted power-split continuously variable transmissions as a credible alternative to powershift-type transmissions in specific specialist applications where the additional purchase price could be justified. However, there is little scientific evidence to suggest that there are significant improvements in overall vehicle performance to be gained through the use of a CVT tractor compared to a well operated powershift-type transmission. Improvements to gearshift quality and more intelligent use of the powertrain control features could ensure powershift-type transmissions remain competitive for the foreseeable future. A dynamic mathematical powertrain model was developed for a lOOkW, 16 speed semi-powershift transmission, four wheel drive tractor based on fundamental Newtonian principles. With the addition of implement models, this allowed accurate representation of the tractor-implement system and provided a platform to develop improved vehicle control strategies. Validation of the model with experimental data showed it was an accurate representation of the real system. The steady state and transient field performance of the tractor operating with a mouldboard plough, a power harrow and a laden trailer was determined for a number of tractor-implement configurations across a range of conditions. This provided a David Sayer, 2005 Cranfield University, Silsoe 11 large dataset for this vehicle for use in this, and other investigations. The level of powertrain loading for field experiments was found to be influenced by soil type, implement working width and depth as well as forward speed and engine speed. For the road investigation, the surface quality and terrain were major influencing factors on performance. It was found there was considerable variation in tractor response to the different gearshift types experienced in the semi-powershift transmission: the non-powershift changes being severe, particularly during downshifts; double-swap powershifts were markedly more severe than single-swap shifts. A unique investigation of the tractor driveline torque loss characteristics across the full operating spectrum using the axle dynamometer identified that the torque losses for this transmission are predominantly speed, rather than torque related. A mathematical model was developed to predict driveline torque losses from transmission output speed, flywheel torque and the number of power-transmitting gears in mesh. The axle dynamometer was also used to successfully replicate field loading patterns in real time. Throughout this investigation a number of undesirable powertrain characteristics were identified. Potential improvements to vehicle performance through the development of solutions to these characteristics have been made either through analysis of field data, experiments with the axle dynamometer, or using the developed mathematical model.Item Open Access Analysis of surface roughness in relation to soil loss and runoff at high rainfall intensities.(John Wiley & Sons, Ltd, 2002-08-30T00:00:00Z) Idowu, O. J.; Rickson, R. Jane; Godwin, R. J.The decay of roughness is an important factor governing surface processes such as infiltration and soil erosion. Thus the decay of surface roughness under different surface conditions was investigated and related to quantitative amounts of soil loss, runoff and sediment concentration in a laboratory experiment. Rainfall with an intensity of 128 mm/h was applied to a bare or mulched surfaces of a sandy loam soil with known surface roughness at specified time intervals. The decay of roughness as expressed by roughness ratio, in this experiment, was better predicted when related to an exponential function of the square root of cumulative kinetic energy of rainfall rather than with the cumulative rainfall. The roughness decay equations in literature did not predict breakdown under mulched surfaces accurately. Thus the exponent parameters of the roughness decay equations were adjusted to reflect the reduced decay occurring under mulched surfaces. In a bare soil, regression equations expressing the dependent variables as a function of initial roughness index were significant, but with low coefficients of determination, being 0.39 for soil loss, 0.12 for runoff and 0.36 for sediment concentration. In addition to initial roughness index, cumulative kinetic energy of rainfall was further included in the regressions. This led to an increase in coefficients of determination, which was 0.81 for soil loss, 0.74 for runoff and 0.49 for sediment concentration. The coefficients of determination (0.87 for soil loss, 0.85 for runoff and 0.51 for sediment concentration) were further increased when the final roughness index was included in addition to initial roughness index and cumulative kinetic energy in the regressions. This work shows that soil loss and runoff could be predicted from bare soil surface provided the initial roughness and the energy of rainfall is known. However, field verifications of these relationships are needed under different tillage tools and under natural rainfall. Copyright (C) 2002 John Wiley Sons, Ltd.Item Open Access Calibration methodology for mapping within-field crop variability using remote sensing(Elsevier, 2003-04) Wood, G. A.; Taylor, John C.; Godwin, R. J.A successful method of mapping within-field crop variability of shoot populations in wheat (Triticum aestivum) and barley (Hordeum vulgare L.) is demonstrated. The approach is extended to include a measure of green area index (GAI). These crop parameters and airborne remote sensing measures of the normalised difference vegetation index (NDVI) are shown to be linearly correlated. Measurements were made at key agronomic growth stages up to the period of anthesis and correlated using statistical linear regression based on a series of field calibration sites. Spatial averaging improves the estimation of the regression parameters and is best achieved by sub-sampling at each calibration site using three 0·25 m2 quadrats. Using the NDVI image to target the location of calibration sites, eight sites are shown to be sufficient, but they must be representative of the range in NDVI present in the field, and have a representative spatial distribution. Sampling the NDVI range is achieved by stratifying the NDVI image and then randomly selecting within each of the strata; ensuring a good spatial distribution is determined by visual interpretation of the image. Similarly, a block of adjacent fields can be successfully calibrated to provide multiple maps of within-field variability in each field using only eight points per block representative of the NDVI range and constraining the sampling to one calibration site per field. Compared to using 30 or more calibration sites, restricting samples to eight does not affect the estimation of the regression parameters as long as the criteria for selection outlined in this paper is adhered to. In repeated tests, the technique provided regression results with a value for the coefficient of determination of 0·7 in over 85% of cases. At farm scale, the results indicate an 80–90% probability of producing a map of within crop field variability with an accuracy of 75–99%. This approach provides a rapid tool for providing accurate and valuable management information in near real-time to the grower for better management and for immediate adoption in precision farming practices, and for determining variable rates of nitrogen, fungicide or plant growth regulators.Item Open Access Comparison of alternative tillage systems(Cranfield University, 2007-09) Vozka, Petr; O’Dogherty, M. J.; Godwin, R. J.The aim of the project was to compare the performance and the costs of alternative tillage systems and machinery, in both energy and economic terms. To determine the energy requirements of tillage implements, experimentation in field conditions and controlled laboratory was conducted. Costs of alternative implements and complete systems were analysed. The field experiment was undertaken to determine the performance of tillage implements in real conditions. Draught force and area of disturbance of the implements were measured and specific resistance calculated. The implements involved in the experiment were 4 furrow mouldboard plough, 3 furrow disc plough, disc harrow and 7 winged tines. The mouldboard plough was operating at two different depths. Two tractors were used for execution of the implement and the wheel slip was measured. The soil bin studies were conducted in additional evaluation of the implements. The laboratory conditions ensure the uniformity of each test. The experiment was carried out to determine draught force, area of disturbance and specific resistance. The experiment involved single furrow mouldboard plough, disc plough, disc harrow and winged tines. Winged tines were made up of four different wing widths. Finally, an economic cost calculator was developed to compare the costs of different implements and tillage systems. Technical parameters and current prices of the implements were obtained from the manufacturers. The results from the field experiment show that there is a similar draught force per unit implement for mouldboard and disc ploughs, while draught force of mouldboard plough is significantly higher. The tillage efficiency of all implements is similar, with a mean of specific resistance of 58 kN/m2 and a range of 15 kN/m2. In the soil bin the vertical force preventing penetration occurred for disc plough and disc harrow. The specific resistance of the mouldboard plough had the lowest value, while the specific resistance of disc plough was higher by a factor of 1.65. By increasing the wing width of the tines the draught force was increased but the specific resistance decreased. Comparing the costs of complete tillage systems it was observed that minimum tillage decreases the operational cost per hectare by 30% compared to a conventional system based on ploughing. Direct drilling is the cheapest way to establish a crop, but if herbicide has to be applied the cost per hectare is similar to that of minimum tillage. The costs of different sizes (102, 162, 224 kW tractors) of alternative tillage systems are similar. Namely the cost of mouldboard plough is £ 80.33/ha with a range of £ +2.48/-1.93/ha, the cost of shallow mouldboard plough is £ 68.85/ha with a range of £ +2.02/-1.64/ha, the cost of stubble cultivator is £ 42.05/ha with a range of £ +2.02/-1.27/ha, the cost of direct drill is £ 20.76/ha with a range of £ +0.89/-0.75/ha and the cost of direct drill with herbicide application is £ 43.15/ha with a range of £ +0.41/-0.53/ha.Item Open Access Comparison of soil compaction below wheels and tracks(2005-10-19) Ansorge, Dirk; Godwin, R. J.This study investigated the effect of high axle loads carried on self propelled wheels and tracks on soil bulk density, soil deformation, rut depth, and penetrometer resistance under controlled laboratory conditions. Furthermore pressure distribution below a three and a two idler track was measured. A brief field study was also conducted to compare the results gained under laboratory conditions. The benefit of the “Terra Trac” driving systems compared to wheel type systems was clearly shown in uniform and stratified soil conditions. Soil deformation was reduced to 50 % for the tracks compared to the wheels at an overall load of 12 t and 10.5 t, respectively. Penetrometer resistance showed a very high resistance close to the surface for the tracks. In uniform soil conditions there was no significant increase in penetrometer resistance compared to the control below 400 mm depth. Reducing the inflation pressure to half the recommended inflation pressure reduced soil deformation by 25 %. Three passes of a tire increased soil density by 20 % compared to a single pass. The three idler track showed only a 50 % increase in pressure from the front to the rear sprocket compared to a 100 % increase for the two idler track. Single peaks in pressure below each idler were less pronounced for the three idler track. Unfortunately the advantage in the pressure distribution for the three idler track did not lead to significant improved behavior concerning soil compaction. The advantage of a tracked combine compared to a wheeled combine is also shown in field measurements. The root system of oil seed rape in former track ruts is more developed than in former wheel ruts. Soil physical properties after the passage were compared to the predictions of two models. The tendency was correct, however the real values were largely offset.Item Open Access Continuous mass flow measurement of granular materials(1997-10) Saunders, Stuart P.; Godwin, R. J.This thesis reports on the development of a double inclined plane (DIP) transducer system based upon the principles of force reaction. This transducer had a design specification to measure the true mass of “free” flowing granular materials, primarily agricultural crops, with an accuracy of ± 2 % on total mass flowed for flow rates between 1 and 10 kg/s. Two absolute values are used to assess accuracy in this study, (i) the total mass flowed (kg), a measure of the mass accumulation and, (ii) the mass flow rate (kg/s), a ‘spot’ reading of flow rate. The performance of the novel system has been evaluated through theoretical, laboratory and field studies and consideration has been given to the commercial and business aspects of the manufacture, marketing and further development of the device. Following mathematical and laboratory studies of the sponsors current force reaction transducer - a single reaction device, angular variations were highlighted as having a significant effect upon output. A further study found that the least sensitive reaction plate angle was 55° To overcome this problem, the double inclined plane (DIP) concept was developed, 2 single reaction plates, joined along their apexes, angled at 55 degrees to the horizontal, mounted upon a horizontal strain gauged beam. Angular compensation when tilting the transducer was provided by generating a higher force from the shallower face and a lower force from the steeper face. A mathematical model of the new transducer allowed the output to be predicted to within 1.7 %. Initial calibration was undertaken in the laboratory and tested using a combine clean grain system simulation apparatus. In-situ machine studies were performed by mounting the transducer in a New Holland TF42 combine, firstly on an extended bubble up auger and finally in the drop box, between the clean grain elevator and bubble up auger. Initial pilot studies were conducted with the combine static to calibrate the system and finally a full harvest field trial was undertaken. Over the harvest field trial, the accuracy on accumulated mass was better than 0.9 % over 127 tonnes. Tramline effects upon transducer output were found to be self cancelling, as the resulting positive and negative ‘spikes’ in the signal, when summed over time approximated to zero. Changes in pitch angle, up to 10 degree caused between 1.5 and -2.8 % randomly distributed error. Roll angles up to 7.5 degrees, caused between -0.9 % and 1.7 % randomly distributed error in static trials. Field beans and oilseed rape required calibration constants 6.8 % and 3.1 % lower than that for 12.5 % moisture content wheat, but with adjusted calibration constants, gave excellent repeatable results. Increasing moisture contents of up to 30 % in wheat resulted in the transducer under reading by, on average, 1.6 %. An assessment of manufacturing costs was made and the unit cost was £154.12 each for 30 units reducing to £109.59 each for 3000 units. It is recommended a pricing objective of maximising sales growth is used which will position the device at the less expensive end of the market. Due to commercial sensitivity, a draft patent has been written to protect the DIP concept. The first stages of commercial adoption already being undertaken by a major multi-national agricultural machinery company, who are evaluating a pre-production prototype. This thesis provides the systems, data and principles required to create a novel, commercially practical transducer system, based upon the principles of force reaction. The problem of angular compensation has been overcome in a simple and effective manner offering a relatively inexpensive but accurate method of measuring mass flow rate, which has already received commercial interest.Item Open Access The damaging effect of surface-traffic-generated soil pressures on buried archaeological artefacts(2010-04-12) Dain-Owens, Anne Peregrine; Kibblewhite, Mark G.; Godwin, R. J.; Hann, Michael J.The aim of this work was to investigate the influence of surface loading from conventional field operations on the damage to buried artefacts, both pots and bones. The objectives of this research were a) to investigate the influence of surface loading and resulting breakage relating to the material strengths of buried objects - ceramic (unglazed), and aged bone; b) to assess the magnitudes of peak subsurface pressures transferred through soil under the dynamic surface loading from tyres and other field operations; c) to develop and test an empirical model for predicting the effects of subsurface pressure application on buried objects from surface loads; and d) to explore ways of identifying the potential for damage to buried artefacts under agricultural and other field operations. Experimental investigations were performed in both the laboratory and field. The laboratory work was undertaken to determine the magnitude of subsurface pressure at which buried objects were damaged. Conducted in a sandy-loam-filled soil bin, instrumented ceramic and bone artefacts were buried alongside pressure sensors and subjected to loading by a single smooth tyre appropriately loaded and inflated for subsurface pressure generation. The breakage of the buried objects and the pressures under the moving tyre were recorded in order to allow correlation of the subsurface pressures to buried artefact breakage. The fieldwork was done to determine the magnitudes of subsurface pressure generated by individual field operations whilst travelling in a similar sandy loam field soil. Four plots were established, with each assigned a particular cultivation regime. An accelerated timeframe was utilized so that a years’ series of field operations could be driven over pressure sensors buried in the soil. The peak pressures from each field operation within each plot were recorded and summarized, and the data was analysed relative to field operation type and cultivation regime type. Multiple statistical analyses were performed, as the laboratory data and field data were independently evaluated before being correlated together. An empirical relationship between buried object damage and subsurface pressure magnitude was developed. The different pot types and bone orientations broke at different subsurface pressures. The four pot types listed in ascending order of strength to resist damage (with breakage pressure threshold value) are: shell tempered (1.3 bar), grog tempered (1.6 bar), flint tempered (3.1 bar), and sand tempered (3.6 bar). Aged human radius bones were tested, and the parallel bone orientation proved stronger than the perpendicular orientation, where 2.8 bar was the lowest subsurface pressure found to cause damage. The primary field operations, presented in ascending order relative to peak magnitude of subsurface pressure per specific operation, are: roll (0.68 bar), drill (1.03 bar), heavy duty cultivator (1.21 bar), spray 1 (1.27 bar), harvester (1.30 bar), spray 2 (1.31 bar), tractor / trailer (1.46 bar), shallow mouldboard plough (1.61 bar), deep mouldboard plough (2.04 bar). The relationships between vehicle specification and subsurface pressure generation potential were described, relating to the vehicle mass, tyre/track physical properties, and tyre inflation pressure. The effect of cultivation method on overall magnitude of subsurface pressure was defined, with lowest pressure generation within a zero-till cultivation regime (1.08 bar), higher in a non-inversion cultivation regime (1.13 bar), followed by the shallow inversion regime (1.22 bar), and highest within a conventional inversion scheme (1.30 bar). The laboratory and field results were correlated by a statistical analysis comparing breakage point to peak subsurface pressure. The shell tempered pot was found to be most susceptible to damage. The grog tempered pot was less vulnerable to damage, followed by the flint tempered pot. The quartz tempered pot was predicted to survive intact under all field operations within this research. In conclusion, this research has developed a functional and predictive empirical relationship between damage to pot and aged bone artefacts from subsurface soil pressures generated by surface traffic. It has been found that different types of buried pot and bone artefacts break at different subsurface pressures. In addition, a complete dataset consisting of peak subsurface pressures recorded under a year’s range of field operations within a sandy loam soil at field-working moisture content has been compiled. The effect of different cultivation methods on the generation of subsurface pressures was also evaluated. The breakage thresholds specific to each artefact type have been related to the in-field subsurface soil pressures. A correlation of breakage to the subsurface pressures under each operation yields a prediction of percentage of artefact-type breakage. From this correlation, relationships are observed between vehicle specification, subsurface pressure generation, and consequential artefact breakage. The achievements provide knowledge about how field operations affect specific types of buried archaeology, providing a valuable asset to farmers, land managers, and regulatory bodies. It is evident that agricultural practices, choice of track or tyre type, and inflation pressures must be carefully managed if the intention is to protect or mitigate damage to buried archaeological artefacts. Thus, a contribution has been made to the development of ‘best management practices’ and to the specification and use of field operations relative to intended mitigation of buried artefact damage.Item Open Access Detection of soil compaction using soil electrical conductivity(Cranfield University, 2007-09) Krajco, Jozef; Waine, Toby W.; Godwin, R. J.Conventional methods for soil compaction mapping, such as penetrometers, although accurate, work as stop-and-go providing point measurements. This process is both time consuming and labour intensive. On-the-go electrical Conductivity (EC) measurements such as electromagnetic induction (e.g. EM38) are affected by key soil properties including texture, moisture content and compaction, so offer a possible rapid alternative for compaction detection. Therefore, the aim of this work is the detection of the within-field variability of soil compaction using soil electrical conductivity for improved soil management. A methodology for identification of within-field variability and for comparison of the data collected by contact and contact-less EC sensors, soil compaction sensor (which contains of eight instrumented wedge faces attached to the leading edge of a tine) and cone penetrometer was developed and a randomised block design experiment was performed. The data was evaluated statistically, the maps of spatial variability were created and the areas for targeted soil loosening were determined. A key finding was the development of application maps for targeted soil loosening, based on soil electrical conductivity measurements. The practical utilisation of this method assumes the presence of two maps that would be compared. The initial map has to be created for the soil in desirable loosened conditions and will be used as a standard for further comparisons. Further map will characterize the conditions of the compacted soil. It is recommended that both maps would be obtained in similar conditions to minimize the effect of soil moisture. The application map can be then created either manually using visual comparison of both initial (loosened soil condition) and further map (compacted areas), or using an appropriate geostatistical tool, in this case a ratio of the two maps. It was found out that the EC readings collected by the Conductometer at depth range of 0-0.3 m are able to distinguish the soil areas with no compaction above 0.3 m and the soil compacted within whole profile. The EC readings obtained at depth range of 0-0.9 m can distinguish the soil zones with no compaction above 0.6 m from the rest of the field. Using the EC data obtained at both depth ranges it is possible to determine three different environments within the field: one with no compaction above 0.3 m, one with no compaction above 0.6 m and one containing the soil compacted within whole profile. The best results for determining the areas with different depths of soil compaction were obtained by soil compaction sensor and cone penetrometer. However the absolute values of soil compaction sensor were affected by small changes in soil texture. The slow data collection speed of point penetration resistance measurement technique practically limits the spatial resolution of final data set. The soil compaction sensor has to be attached on the frame of the subsoiler and although it provides precise readings, it has high energy requirement. The high labour and time requirements are the main disadvantages of penetration resistance measurements. Second most precise determination of the areas with different soil compaction presence was provided by the EC data collected by the Conductometer which is able to collect data on-the-go with much lower power requirements. EM38 operated in horizontal mode distinguished the areas with no compaction above 0.3 m and areas with soil compacted at whole profile with less precision. The same instrument operated in vertical mode was not sensitive enough to measure any differences in soil bulk density.Item Open Access Developing strategies for spatially variable nitrogen application in cereals II: wheat(Elsevier , 2003-04) Welsh, J. P.; Wood, G. A.; Godwin, R. J.; Taylor, John C.; Earl, R.; Blackmore, S.; Knight, S. M.For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of winter barley (Hordeum vulgare L.) over three seasons. The aim of which was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate varied from 90 to in excess of 160 kg [N] ha−1 in different parts of the field, which supports the case for applying spatially variable rates of N. This, however, is highly dependent on seasonal variations, e.g. the quantity and distribution of rainfall and the effect that this has on soil moisture deficits and crop growth. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, based on 3 yr of yield data, were inconsistent, and it was concluded that that this approach, which is currently the most practical commercial system, does not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that applying additional N to areas with a low shoot population and reducing N to areas with a high shoot population resulted in an average strategy benefit of up to 0·36 t ha−1 compared with standard farm practice.Item Open Access Developing Strategies for spatially variable nitrogen application in cereals, I: Winter barley(Elsevier , 2003-04) Welsh, J. P.; Wood, G. A.; Godwin, R. J.; Taylor, John C.; Earl, R.; Blackmore, S.; Knight, S. M.For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of winter barley (Hordeum vulgare L.) over three seasons. The aim of which was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate varied from 90 to in excess of 160 kg [N] ha−1 in different parts of the field, which supports the case for applying spatially variable rates of N. This, however, is highly dependent on seasonal variations, e.g. the quantity and distribution of rainfall and the effect that this has on soil moisture deficits and crop growth. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, based on 3 yr of yield data, were inconsistent, and it was concluded that that this approach, which is currently the most practical commercial system, does not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that applying additional N to areas with a low shoot population and reducing N to areas with a high shoot population resulted in an average strategy benefit of up to 0·36 t ha−1 compared with standard farm practice.Item Open Access The development and application of spatial information systems for environmental science(Cranfield University, 1998-04) Hallett, Stephen H.; Bullock, P; Godwin, R. J.This thesis shows how advances in IT allow the development of Environmental Information System (EIS) applications contributing to the advancement of environmental science and management. The research presented elucidates and evaluates the applications for EIS within the environmental and natural resource sciences with specific reference to soils. In supporting environmental suitability and risk assessment, the following research objectives were met: 1. Derive and construct new datasets, facilitating the development of EIS applications 2. Using these and other datasets, develop and demonstrate the validity of specific spatial EIS applications within the context of sustainable soil resource management 3. Evaluate, develop and apply emergent technological principles such as the objectoriented paradigm to the development of such EIS applications The research shows that the EIS approach offers environmental researchers and practitioners powerful tools to facilitate the collection and preparation, representation, structure and management, manipulation and presentation of environmental data. Such data can be used to aid disciplinary and interdisciplinary scientific research, such as risk modelling, data quality control and longitudinal studies. Through the interaction of multi-disciplinary datasets and models, the EIS contributes to the development of a holistic, interdisciplinary understanding of pertinent and contemporary environmental issues. EIS applications are constrained by the availability and affordability of technology, as well as by the quality of the data, models and scientific research they are based upon. With the constantly improving capabilities and cost-performance of IT there should be a continual review of methodologies to maximise usage of available technology. A well-developed synergy between environmental science and IT is important and automatic adoption of the most recently emergent information technologies is not always to be recommended for EIS development. The choice of software tools utilised in EIS development must be based upon the requirements for integration with existing systems, reliability, adherence to industry standards, expenditure, staff training needs, experimentation and efficiency. The incorporation of a spatial element within the decision-making process extends a powerful visual dimension to the traditional approaches used to portray environmental systems. The research identifies the emergent 'object paradigm' as significant for EIS development, being effective for describing complex spatial environmental phenomena. An object-oriented approach facilitates the presentation of abstracted, packaged scientific information in a directly accessible form. The EIS offers a powerful strategic tool for supporting decision-making in environmental management. The EIS applications presented supported Soil Quality and Protection, Pollution Control and Impact Assessment, Water Resource and Catchment Management, Soil and Land Management and Environmental Risk Assessment.Item Open Access An Economic analysis of the potential for precision farming in UK cereal production(Elsevier , 2003-04) Godwin, R. J.; Richards, Terence E.; Wood, G. A.; Welsh, J. P.; Knight, S. M.The results from alternative spatial nitrogen application studies are analysed in economic terms and compared to the costs of precision farming hardware, software and other services for cereal crops in the UK. At current prices, the benefits of variable rate application of nitrogen exceed the returns from a uniform application by an average of £22 ha−1 The cost of the precision farming systems range from £5 to £18 ha−1 depending upon the system chosen for an area of 250 ha. The benefits outweigh the associated costs for cereal farms in excess of 80 ha for the lowest price system to 200–300 ha for the more sophisticated systems. The scale of benefits obtained depends upon the magnitude of the response to the treatment and the proportion of the field that will respond. To be cost effective, a farmed area of 250 ha of cereals, where 30% of the area will respond to variable treatment, requires an increase in crop yield in the responsive areas of between 0·25 and 1.00 t ha−1 (at £65 t−1) for the basic and most expensive precision farming systems, respectively.Item Open Access The effect of organic farming on soil physical properties, infiltration and workability(Cranfield University, 2011-02) Hathaway-Jenkins, Laura Jane; Godwin, R. J.; Sakrabani, Ruben; Whitmore, A.; Pearce, B.Organically managed land has increased to 4 % of the total area of agricultural land in the UK. Changing land management can impact upon the rural environment (soils, hydrology and biodiversity) and rural community (socio-economics and culture). This thesis aims to compare the effects of organic farming practices on soil physical, chemical and hydrological properties in relation to conventional farming systems. The research combines data from three different scales: field measurements, plot measurements and catchment modelling. At the field scale: 16 pairs of farms (organic and conventional between 50 and 3000 m apart) located in England, over a range of soil textures: clayey, silty, medium and coarse were investigated. There were also two different land uses (grass and winter wheat). Data was obtained on soil properties including: shear strength, Atterberg limits, field capacity, aggregate stability, HOST values, infiltration rates and Soil Organic Carbon (SOC). The analysis of the data shows that, whilst it is possible to detect the effects of both soil texture and land use (grassland / arable) on a number of the soil properties; there is no evidence that organic farming improves soil properties or physical condition - equally there is no detrimental effect. This is in agreement with the results of a number of other European studies. There was evidence to show that infiltration rates are greater on organically managed grassland than conventional grassland; which agrees with the HOST analysis where fewer fields were degraded under organic management. Fewer traces of pesticides and herbicides were in the soil water from the organic fields compared with the conventionally managed fields; none were at a level which would contribute to agricultural pollution. Cont/D.Item Open Access The effect of tyres and a rubber track at high axle loads on soil compaction, Part 1: Single axle-studies(Elsevier, 2007-09) Ansorge, Dirk; Godwin, R. J.One option for ground drive systems with large harvesting equipment is to use rubber-belted tracks; however, little is known about the performance of these systems relative to appropriately sized pneumatic tyres. The effect of self-propelled wheels and a track with high axle loads (9–24 t) on soil compaction were studied. Soil displacement and soil density changes were assessed by embedding talcum powder lines as tracer into the soil during preparation. In addition, soil dry bulk density and penetrometer resistance were measured. The track with loads of both 10.5 and 12 t compacts the soil less than wheels at a 10.5 t load in both weak uniform and stratified soil. Towed implement wheels with a 4.5 t load caused similar soil displacement to the track with a load of 12 t. Tyre inflation pressure had a significant influence on soil parameters. To reduce compaction a larger overall diameter was found to be more beneficial than a wider tyre. This emphasised the importance of contact pressure and its distribution with respect to soil density changes. Total axle loads are less important than how these loads are distributed on the ground.Item Open Access The effect of tyres and a rubber track at high axle loads on soil compaction-Part 2: Multi-axle machine studies(Elsevier, 2008-03) Ansorge, Dirk; Godwin, R. J.This paper reports on a study of the effect of the passage of multi-axle harvesting machines on the soil physical properties. In particular, it investigates the effect of the rear tyre of a combine harvester on the amount of soil compaction subsequent to the passage of the front tyre/track. The work was conducted in controlled laboratory conditions to determine the effect of a simulated self-propelled combine harvester with a total machine weight of 30–33 t. This was assessed by embedding talcum powder tracer lines in the soil to measure soil displacement and soil density changes. Dry bulk density and penetrometer resistance were also measured. The results showed that the benefit of the rubber track found by Ansorge and Godwin [2007a. The effect of tyres and a rubber track at high axle loads on soil compaction: Part 1: Single Axle Studies. Biosystems Engineering 98 (1), 115–126] was maintained after the additional passage of the rear tyre. After the passage of a track the effect of rear tyre size was insignificant, but the rear tyre size had a significant influence on soil density when following a leading tyre. This was due to a higher strength layer at the soil surface created by the track which was able to withstand the load of the subsequent passes and protect the soil below from further compaction. Results similar to those found for a tracked machine were also achieved by three passes of a 900 mm section width tyre at 5 t load and 0.5 bar inflation pressure. The track results for the 33 t machine were very similar to those of a smaller combine harvester with a total load of 11 t and similar rut width. The study confirmed the benefit of tracks with regard to soil compaction and emphasised the fact that total axle loads and machine weights are less important than how the loads are distributed to the soil.Item Open Access The effects of low and controlled traffic systems on soil physical properties, yields and the profitability of cereal crops on a range of soil types(Cranfield University, 2011-04) Chamen, W. C. T.; Mouazen, A. M.; Godwin, R. J.Soil compaction is an inevitable consequence of mechanised farming systems whose machines are degrading soils to the extent that some are considered uneconomic to repair. A number of mitigating actions have been proposed but their ability to reduce or avoid damage has not been well tested. The aim of this research was to determine whether actions to reduce damage have been, or are likely to be effective and to assess whether the practice of controlled traffic farming (confining all field vehicles to the least possible area of permanent traffic lanes) has the potential to be a practical and cost effective means of avoidance. The literature confirmed that soil compaction from field vehicles had negative consequences for practically every aspect of crop production. It increases the energy needed to establish crops, compromises seedbed quality and crop yield, and leads to accelerated water run-off, erosion and soil loss. It is also implicated in enhanced emissions of nitrous oxide and reduced water and nutrient use efficiency. Replicated field trials showed that compaction is created by a combination of loading and contact pressure. Trafficking increased soil penetration resistance by 47% and bulk density by 15% while reducing wheat yield by up to 16%, soil porosity by 10% and infiltration by a factor of four. Low ground pressure systems were a reasonable means of compaction mitigation but were constrained due to their negative impact on topsoils and gradual degradation of subsoils whose repair by deep soil loosening is expensive and short lived. Controlled traffic farming (CTF) was found to be practical and had fundamental advantages in maintaining all aspects of good soil structure with lowered inputs of energy and time. On a farm in central England, machinery investment with CTF fell by over 20% and farm gross margin increased in the range 8-17%.Item Open Access The effects of tyre systems on the depth and severity of compaction(Cranfield University, Cranfield University at Silsoe, 2006-11-01T15:09:33Z) Stranks, Simon Nicholas; Godwin, R. J.; Dresser, M. L.High value crops such as peas for the frozen vegetable market have to be harvested at the optimum point for quality, regardless of field conditions. Six wheeled pea harvesters with a gross weight of 27 t, giving a wheel load of 4.5 t are required to move from field to field with optimum timeliness. In order to achieve road speeds of 25 km/h an inflation pressure of 2.2 bar is required for the specific tyre load speed rating. Typically, in field conditions, this inflation pressure is not reduced and therefore the likelihood of soil damage is increased. This study was undertaken to examine the effects of tyre section width and inflation pressure on rolling resistance, rut depth and sub-surface soil deformation. Under controlled laboratory conditions three tyres, at three inflation pressures, with a load of 4.5 t were passed over a soil at three different initial bulk densities. Measurements of dry bulk density, rut depth, rolling resistance, cone penetrometer resistance and soil deformation through the profile were taken before and after the passage of the tyres. The results show that by increasing the tyre size and reducing the inflation pressure the depth at which compaction occurs and rut depth decrease by 44%. The 800 mm section tyre causes less compaction than any of the other tyres tested especially when inflated to 1.6 bar. Rolling resistance is reduced when the tyre is inflated to the optimum for each tyre. The change in bulk density when plotted against either initial bulk density or penetration resistance results in a set of curves which can be used by the manufacturer, farmer or operator to select the correct tyre section width and inflation pressure for field conditions. As a result of this study the harvester manufacturers are investigating the engineering requirements of increasing tyre section width to 800 mm and are now equipping pea harvesters with central tyre inflation systems. The benefits of which would be to significantly reduce the amount of soil compaction, reduce rolling resistance and save the operator £455 000 per annum in fuel costs.Item Open Access The evaluation of ground based remote sensing systems for canopy nitrogen management in winter wheat(Cranfield University, 2007-04) Havránková, Jana; Godwin, R. J.; Wood, G. A.Nitrogen management is a crucial issue in terms of environmental and economical efficiency for winter wheat husbandry. Precision Agriculture in particular Remote Sensing, has been used to determine the variability of the crop. However, to be able to apply the required rate of nitrogen, the calibration of the data with the crop characteristics is critical. Satellite, airborne and ground based platforms are possible to use. Despite the presence of some commercial applications of the satellite and airborne techniques, the ground based systems offer advantages in terms of availability. The most common passive ground based remote sensing system in Europe is the Yara N sensor which has limitations in poor light conditions. Active sensors, using their own energy sources, are now available in the market e.g. the Crop Circle (Holland Scientific) and the Yara N sensor ALS. The aim of this work was to evaluate the active and passive ground based remote sensing systems for canopy nitrogen management in winter wheat. The work was divided into three sub-experiments. Two were conducted in Wilstead (UK) in 2005 and 2006, with the objective to determine the relationship between sensors output (NDVI) and crop (wheat) characteristics during the growing season and to evaluate their application in field management of winter wheat. The field experiment carried out in Oponice (Slovakia) in 2006 assessed three different management strategies (the real time, near real time and traditional nitrogen management). The results showed that both the active and the passive sensors determine the variability in shoot numbers and total nitrogen content of plants particularly in the early growth stages. The application of Nitrogen using these sensors in the UK saved 15kg N/ha (UK). The nitrogen saved in Slovakia was small (1.5 kg/ha). Use of the sensors enabled a reduction in nitrogen without a negative influence on yield, which increased the Nitrogen use efficiency. In addition to this there were potential environmental benefits through a 52% reduction of the residual Nitrogen in the soil in the UK. In Slovakia there was no significant overall reduction in the total nitrogen used; however, a different application rates was applied to 80% of the field. The overall cost of production in Slovakia using the sensors was increased by 5%. The cost of sensing in the UK was £11/ha which could be offset by the 15 kgN/ha reduction and a potential small increase of yield by 1%.Item Open Access The evaluation of the soil pressure distribution and carcass stiffness resulting from pneumatic agricultural tyres(Cranfield University, 2010-08-03) Misiewicz, Paula Aleksandra; Godwin, R. J.; Richards, Terence E.Introducing loads onto the soil via pneumatic tyred equipment is the major cause of compaction of agricultural soils, which causes damage to the soil-water-air-plant system. The degree of soil compaction is largely influenced by the loads applied to the soil and resulting surface and subsurface pressure. Therefore, this study was conducted in order to determine an effective method to measure the pressure distribution under a selection of pneumatic agricultural tyres on a hard surface and in the soil profile. As a result of this, it has been possible to evaluate the influence of tyre inflation pressure, load, ply rating and tread pattern on the resulting pressure. Also, the carcass stiffness of the tyres studied was determined and alternative methods to predict the carcass stiffness were evaluated and an improved technique was developed. Cont/d.Item Open Access Exploratory study into the acceptance of 'on farm' automated traceability systems(Cranfield University, 2009) Pegurara Gasparin, Carla; Godwin, R. J.; Blackburn, D. W. K.The increasing pressure from retailers and consumers require that all farmers collect traceability data regarding the crops they produce and the name and application rate of the agrochemicals that they have used to produce them. In order to achieve this, automated traceability systems could be used to assist farmers in collecting the data required throughout the food chain to the market place. An Automated Agrochemical Traceability System (AACTS) was designed and developed at Cranfield University (Peets, 2009). This system is capable of automatically identifying and assisting in the precise weighing of the agrochemical loaded into a sprayer. The actual amount applied to crops growing in any given section of the field would then be recorded from the application maps obtained using precision farming methods. This work aims to identify the factors that inform the development of and the potential market uptake of the AACTS. Interviews with representatives of the interest groups in the food chain were conducted in order to identify their perceptions regarding traceability systems. Moreover, ten farm sprayer operators were asked to judge the sprayer with AACTS against sprayer without AACTS in terms of ease of filling, data management, investment cost, operator safety and accuracy of the data. The food industry supports the need for the AACTS and will accept the new technology if it reduces cost, time, business risk and increases value of certified produce. It was found that the weighted ranking of the sprayer with AACTS was greater than the sprayer without the AACTS at 0.68 opposed to 0.32 respectively. Peets (2009) showed that the AACTS has a resolution within 1 g with the engine switched off and 3.6 g when it is not. Furthermore, there is no significant difference in speed of operation between the AACTS and the manual method including loading and record creation time at the 5% probability level. The system would also automatically create the record of the agrochemicals used, their application rate and field distribution pattern. The price that a farmer would be willing to pay for the AACTS is positively related to the size of arable holding land, the cost of sprayer and the perception of the need towards the AACTS as found using an online questionnaire. Out of 119 respondents, 42% of the respondents perceived the need for the AACTS. This study estimated thedemand curve of the AACTS, according to this curve 4% of the farmers would buy the AACTS if it costs £3,500, 54% would buy if it cost £1,500 and 100% would buy it if it cost £200. According to the demand curve and production cost, the highest profit for the manufacturer of the AACTS could be obtained with retail price of £2,000 in Europe. Twenty seven face to face interviews were conducted with farmers in England to identified the perceived main benefits, these were; the potential improvement of stock control in the chemical store, the avoidance of use of incorrect agrochemicals, the reduction of time in the office for record keeping and improved accuracy when filling the sprayer in terms of both the correct chemical and the dilution rate. However, in order to fulfil the farmers’ requirements the AACTS should allow more rinsing space to wash out 10 and 20 litre containers. Furthermore the software and appropriate database should be programmed to enable the identification and loading of the corresponding generic agrochemical products. The existing traceability systems of three different types of farm enterprise: fresh produce, onion production and a conservation grade cereal farm were analysed and suggestions for improvements were explored. It was demonstrated that the AACTS can avoid market and financial loss for relatively small cost. The operation cost of the AACTS for an area of 900 hectares is £1.29 per hectare. Furthermore, there is a potential time and financial saving if the agrochemical application records are received electronically. However, the savings will depend on the capability of the computer and its reliability. At Clements, the production manager spends around 600 hours per year typing the agrochemical application records into the computer. A range of social science methods were used to estimate the market uptake of the AACTS. These included face-to-face semi-structured interviews with members of the food chain and farmers, the Analytical Hierarchy Process (AHP) to evaluate the prototype system of AACTS, and a Contingent Valuation (CV) questionnaire to estimate the farmers’ willingness to pay for the AACTS. The information gathered from their collective use showed that they provided a valuable suite of methods for product development.
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