A mechanical hoof for simulating animal treading under controlled conditions

Treading by grazing animals can have a significant adverse effect on soil properties and plant growth, particularly under wet soil conditions. It may also affect water and nutrient movement over and through soil. It is difficult to assess treading with live animals under controlled conditions, when the field plots are small or where there are instruments installed. This paper describes a mechanical cow hoof device which can overcome these difficulties. The mechanical hoof consists of an artificial hoof made of mild steel mounted onto a compressed air ram, which, in turn, is driven by an air compressor system. Treading pressure, treading speed, duration of hoof-soil contact, and intensity and location of treading can all be controlled. Tests of the mechanical hoof in a simple field plot experiment showed that, over a 5-8-month period, treading increased bulk density (from 1.18 to 1.29 Mg m(-3)); decreased macroporosity (diam. > 30 mum) (from 16.5% to 10% v/v) in the top 10 cm soil, and reduced pasture yield (from 100 to 91% of relative dry matter yield). The mechanical hoof device can sen e as a useful tool for studying the effect of treading on soil quality indicators, water and solute movement, and plant production under controlled conditions.