The effect of tire tracks on draft force requirements of soil tillage and field traffic systems

Abstract.The aim of this paper is to report the draft force requirements for different tillage and traffic treatments in a sandy loam soil for the establishment of oil seed rape, and to determine the effect of tire tracks on draft forces. Nine combinations of three traffic systems (random traffic farming-RTF, low ground pressure-LGP, controlled traffic farming-CTF) and three tillage methods (deep tillage-250 mm, shallow tillage-100 mm, zero tillage) were randomly assigned with four replications. The experimental plots were 80 m long and 4 m wide with 0.7 m tire track widths. First a cultivator frame was equipped with three narrow tines; two were positioned in the tire tracks and the third in line with the center of the tractor where there was no effect of traffic. Each tine was strain gauged to measure the differences in draft force of the tine in the soil conditions in the tire tracks and the non-compacted central section of the plots. These tine tests were conducted in RTF and CTF plots only. Secondly, the draft forces were measured in all treatments during the single pass cultivations and drilling operations. Average draft forces were different in shallow and deep tillage, as expected (P<0.1). Despite an approximate 10% greater draft force required for the RFT plots compared to CTF plots during cultivation experiments, the difference was not significant. Draft forces were the same for drilling operations (P<0.1). Regarding the tine experiments, approximately 47% and 49% more force was needed in the tire tracks during shallow tillage operations, respectively for RTF and CTF plots compared to the non-trafficked sections. Thus, the field traffic method showed no relative differences in the draft forces measured over the compacted andnon-compacted zones in shallow tillage. In deep tillage, the tine draft force requirements were estimated to be 13% and 39% less in the non-compacted zone, respectively for RTF and CTF treatments. These results implied that the CTF treatments resulted in lower force requirements in the non-compacted areas due to the elimination of tire effects in the non-trafficked sections the total width of the plots. CTF systems with 8 m and 12 m base widths would have 17.5% and 11.7% compacted zones, suggesting more potential for more gain in the total draft force that would be needed in other systems than the CTF.