Improvement of Planosol Solum: Part 6, Field Experiments with a Three-Stage Subsoil Mixing Plough

Abstract

This paper deals with the design of a three-stage subsoil mixing plough and field experiments in a planosol solum field in China to obtain mixing of the second (Aw) and third (B) horizons to improve the planosol solum, leaving the first (Ap) horizon undisturbed. The field test results showed that the three-stage subsoil mixing plough was considerably improved over the two-stage subsoil mixing plough used in earlier tests, in terms of soil mixing, clod size produced and draught requirement. The optimum specification for the elements of the three-stage subsoil mixing plough was as follows. First plough body: working depth should be 250 mm and working width 460 mm. Second plough body: working depth should be 200 mm from the bottom of the first plough body and working width 300 mm. Third plough body: working depth should be 138 mm from the bottom of the second plough body and working width 300 mm. With this combination, there was a good draught balance with each plough body requiring about 10 kN, and giving a total of about 30 kN overall.