K. Araya

An Explosive Subsoiler for the Improvement of Meadow Soil, Part 3: Field Experiments

Abstract An explosive subsoiler was envisaged for the achievement of greater soil rupture volume and longer sustainability of drainage to improve meadow soil. A prototype explosive subsoiler was designed and built in Japan and sent to China, and actual field tests were conducted in a meadow soil field. This paper details the performance of the explosive subsoiler in the meadow soil. The results showed that when the soil penetration resistance was less than 3·0 MPa, and gas of 10 g/s was injected, a pressure of about 5 kPa was produced at the nozzle port. A base draught of about 20 kN, which was measured when no gas was injected, was reduced to 15 kN. The trace of the subsoiler remained in the soil horizon, and a cavity was formed on the trace of the subsoiler chisel. When the soil penetration resistance was more than 3·0 MPa, the draught reduction could not be obtained even with the pressure produced on the nozzle port. There was a chisel trace in the soil horizon, but there was no cavity formation by the injected gas. The draught of the mouldboard plough body which tilled the Ap horizon was about 10 kN with a working depth of 200 mm. The mean base draught of the subsoiler body, which broke the A and Cg1 horizons, was about 10 kN at 478 mm depth from the soil surface, about 20 kN at 539 mm depth and about 30 kN at the 600 mm depth.