Soil Movement resulting from Sweep Type Liquid Manure Injection Tools

Knowledge of soil movement is important for the design and selection of injection tool to minimise agronomic and environmental concerns associated with liquid manure injection. Laboratory studies were conducted in an indoor soil bin to investigate soil movement in three directions resulting from sweep type injection tools. The first study was carried out to select point tracers. Three tracer sizes (10, 15 and 20 mm) and four tracer materials [wood, polyvinyl chloride (PVC), aluminium and steel] were tested for measurements of soil movement resulting from a sweep at constant injection depth and tool forward speed. The test results led to the selection of the 10 mm PVC tracers for the subsequent soil movement study. In the soil movement study, three sweeps (small, medium and large) were tested at three injection depths (50, 100 and 150 mm), two tool forward speeds (0·6 and 1·4 m s−1), and two soil moisture contents (14 and 18%). The selected tracers were used to measure soil movement in forward, upward and lateral directions. Increasing injection depth from 50 to 150 resulted in a 39% increase in the soil forward movement and a 37% increase in the upward movement. The higher tool forward speed produced a 31% higher forward movement and a 56% higher lateral movement. The higher soil moisture content increased the soil upward movement by 17%. The large sweep resulted in a 27 and 48% greater forward movement than the medium and small sweeps, respectively.