Paula A Misiewicz

Results From Recent Traffic Systems Research And The Implications For Future Work

Abstract This paper reviews the results of recent traffic systems research and concludes that the evidence shows that with sufficient ingenuity by farmers and their equipment suppliers to match operating and wheel track widths, the traffic management systems that reduce soil compaction should improve crop yield, reduce energy consumption and improve infiltration rates (which will reduce runoff, erosion and flooding). These together will improve agronomic, economic and environmental sustainability of agriculture. Low ground pressure alternatives may well be the option that best suits some farming enterprises and should not be discounted as viable traffic management methods. The paper also considers the implications for further work to improve the robustness of the experimental data.

Techniques for estimating contact pressure resulting from loaded agricultural tyres

Recent increases in the weight of agricultural machines can cause soil management problems in the form of soil compaction. Tyre contact pressure is often used as an indicator of the potential for a machine to cause compaction.

An investigation into the effect of traffic and tillage on soil properties using X-ray computed tomography

Abstract. Compaction of soils from agricultural machinery alters soil aggregate and pore structure whilst increasing bulk density. This leads to decreased soil aeration and water and nutrient uptake and increases root penetration resistance that can result in reduced crop yields. A randomised 3x3 factorial traffic (Random Traffic Farming, Controlled Traffic Farming and Low Ground Pressure systems) and tillage (Deep, 250mm; Shallow, 100mm and No-till) field experiment at Harper Adams University, UK, was set up in 2011. An investigation was conducted in 2016 using X-ray Computed Tomography (CT) to assess the effects of tillage and traffic on the soil pore size and distribution. The study highlighted that deep tillage reduces the ability of soil to support vehicular traffic which leads to soil recompaction. Deep tillage caused soil percentage porosity to decrease with depth with corresponding increases in the frequency of smaller size pores. Shallow tillage treatments increased the percentage porosity with depth whilst providing the lowest penetration resistance. Percentage porosity is higher in untrafficked treatments. Further investigation is required to investigate the effect that the complex interactions between soil pore structure and developing root architecture have on crop yield.

Estimations and Measurements of Carcass Stiffness of Agricultural Tires on a Hard Surface

Abstract. Loading soil with agricultural vehicles is a major cause of compaction of agricultural soils. The loads applied to the soil and the resulting pressure influences the degree of soil compaction. This study was conducted to determine an effective method to measure the pressure distribution under a selection of pneumatic agricultural tires and based on this the tire carcass stiffness was determined and methods to predict carcass stiffness were evaluated. The tire carcass stiffness is defined as an equivalent pressure resulting from the tire carcass stiffness and estimated by subtracting the tire inflation pressure from the mean surface contact pressure. To measure the carcass stiffness of a tire the following approaches were considered: The ink footprint method to estimate the size of the contact patch and hence mean contact pressure, Tire load – deflection method, The pressure mapping method to measure both mean and maximum contact pressure using a commercial pressure mapping system Tire manufacturer’s specification data methods (two variants). Carcass stiffness values obtained from the ink footprint method gave results significantly lower (30 – 40%) than those obtained using the pressure mapping system. The method based on the tire load – deflection characteristics was found to give a better estimation of the tire carcass stiffness of the smooth rather than the treaded tire. The technique of using the theoretical load that the tire is able to sustain at zero inflation pressure, produced estimates that were within ± 20% of the mean carcass stiffness determined using the pressure mapping system. It is recommended that this method should be used in the absence of a pressure mapping system and it would be beneficial to users if the results of this could be added to the tire manufacturer’s specification data.