Controlled traffic farming in precision agriculture

In the past few decades, there has been a continuous drive towards the development and adoption of larger, and more powerful, agricultural machinery (Kutzbach, 2000; Jorgensen, 2012). Larger machinery is often related with timeliness, higher work rates and lower labour requirements, which has led to significant improvements both in efficiency and productivity (Vermeulen et al., 2010). A drawback of this trend has been the associated increase in machinery weight, which has, to some extent, offset advances made by the industry in developing improved running gear, such as in tyre (e.g. radial ply tyres) and track technology (e.g. rubber belts) to reduce contact pressures (Ansorge and Godwin, 2008; Antille et al., 2013; Misiewicz et al., 2015). The progressive increase in axle loads, as observed for example with harvesting equipment (e.g. Ansorge and Godwin, 2007; Bennett et al., 2015), means that soil stresses have also continued to increase, extending deeper into the subsoil (e.g. ≥0.3 MPa at 400 mm deep) and exceeding historic values, such as those resulting from in-furrow ploughing (Koolen et al., 1992; Chamen, 2015).