Influence of the speed on soil-pressure over a plough

During ploughing work wear is generated by the interaction between tillage tool and soil. Wear rate on tillage tools is mostly affected by soil-tool pressure distribution and it compromises plough functionality during its life cycle. In this paper, a methodology to measure and analyse pressure signals on a plough has been developed and the influence of the speed was investigated. Field tests were carried out with a four-furrow plough and the pressure on 10 different points was measured with tactile sensors. The plough was tested on a silty-clay-loam soil at three different speeds. The analysis of the results shows that pressure signals are close to zero for a range from 14 up to 92% of the travelled distance and short spikes frequently occur. This behaviour can be explained by the granular structure of soil that determines a non-constant contact between the soil and tool in some points. Spike patterns are markedly affected by the speed especially in terms of the number of spikes and their distribution. Moreover, the mean pressure quadratically varies with the speed in mouldboard (MBL) and ploughshare (PS) while on wear plate (WP) no influence was found because this part is parallel to the ploughing direction. The methodology and the results introduced in this paper will be useful for the validation of mathematical models to simulate the ploughing process but also, to improve the comprehension of the soil cutting process.