Soil adhesion and biomimetics of soil-engaging components: a review

Adhesive forces exist between soil and the surfaces of soil-engaging components on a variety of terrain machines including tillage and sowing machines. This phenomenon of soil adhesion not only increases the working resistance and energy consumption of these machines, but also decreases the quality of work. Characteristics of soil adhesion to solid surfaces, behaviour and principles of soil-burrowing animals for improved soil scouring and biomimetics of soil-engaging components are reviewed in this paper. The characteristics of soil adhesion to solid surfaces were concerned with: the morphological features of soil at the contact interfaces, contact models of soil adhesion, explanation of soil adhesion, factors affecting soil adhesion and conventional methods for reducing adhesion. Details on the behaviour of soil-burrowing animals include: claw shape; body surface geometry, chemical constitution, liquid secretion and bioelectricity; and body flexing behaviour. The principles of soil-burrowing animals in soil scouring mainly comprise the effects of geometrical morphologies and shapes, hydrophobicity, micro-electro-osmotic systems, lubrication and body surface flexibility. Based on these characteristics, biomimetic methods for reducing soil adhesion to soil-engaging components include: biomimetic non-smooth surfaces; modification of soil-engaging materials; biomimetic non-smooth electro-osmosis; and flexible components. (C) 2001 Silsoe Research Institute.