Discrete element modelling of top soil burial using a full scale mouldboard plough under field conditions

In order to improve the grain crop yield of non-wetting sandy soils, mouldboard ploughs are again being used in Australia. To improve the effectiveness of top soil burial from ploughing the most suitable operating parameters need to be determined. The discrete element method (DEM) has the potential to model soil-mouldboard plough interactions relating to both soil movement and tillage forces. A full scale mouldboard plough was tested in the field and then simulated using DEM. The draught forces predicted by DEM were of similar magnitude to those calculated using ASABE's Agricultural Machinery Management Data (D497.7 R2015). The DEM model predicted top soil burial to a similar depth in the soil profile as was measured in the field. However, DEM predictions of lateral and forward soil movements of the buried top soil were greater than that measured in the field. The DEM predictions showed that increasing speed from 5 to 15 km h−1 gave a 40% increase in draught and a significant reduction in the depth of top soil burial. Increasing the tillage depth from 200 to 350 mm gave a 270% increase in draught but very little change in depth of burial of the top soil. The use of a skimmer was predicted to increase the draught by 4% and increase the amount of top soil buried below 100 mm depth.