Deep Tillage Plough down to 600 mm for Improvement of Salt-affected Soils: Part 2: Draught and Vertical Force Induced on Plough by Brittle Fracture

Abstract

A method is proposed for soil improvement of salt-affected soils. Large soil clods are produced in subsoil by deep tillage to cut off capillarity from groundwater and to prevent the rise of salts to the soil surface. In this paper, the draught and vertical force induced on this plough body by brittle fracture (not by shear failure) was analysed to get the large soil clods in an indoor soil bin with a soil with cement. The results showed that the normal mean peak draught was about 1 kN, and the downward vertical peak force was about 10 kN at 200 mm in the operating depth. When the blade length was short (50 mm or 80 mm) and huge soil clods were produced, the peak draught and vertical force increased to about 2 kN and 20 kN respectively. When the blade length was long (200 and 250 mm) and the operating depth was deep (150 and 200 mm), the peak draught increased abnormally to 4–5 kN. The peak vertical force also increased abnormally to 30–40 kN. The proper length of the plough blade was determined to be 130 mm because of the smallest draught and downward vertical force.