Field experiments evaluating a biomimetic shark-inspired (BioS) subsoiler for tillage resistance reduction

Due to the increasingly severe soil compaction and plough pan thickening prevalent in agricultural practice, an increase in operating energy consumption and a decrease in crop growth has been observed. This paper aims to solve the problem of heavy tillage resistance by using riblet structures extracted from shark scales in the design a biomimetic shark-inspired (BioS) subsoiler. To produce better quality work, the design parameters of the BioS subsoiler, including the ratio of the riblet height to the riblet spacing h/s, the riblet height h, and the internal friction angle α, were considered, and a mechanical analysis of the relationship between the BioS subsoiler and the soil was performed to evaluate tillage resistance, total energy consumption and soil disturbance. The minimum tillage resistance and energy consumption of the shank and tine were achieved with an h of 5 mm and h/s of 0.57 obtained from the simulation results. Then, the parametrically optimized BioS subsoilers were fabricated and used to perform field experiments at different tillage speeds. The effects of subsoiling with BioS subsoilers and with an ordinary subsoiler (O–S) on the soil moisture, root morphology and crop yield were also discussed. The results showed that the BioS subsoiler would be helpful to increase the root absorption capacity of water and nutrients, which promote crop growth and increase the crop yield.