Three-stage Subsoil Interval Mixing Plough for Improvement of Planosol

To improve planosol soil conditions, a new Three-stage Subsoil Interval Mixing Plough (hereafter, TSIM-plough) was constructed in 2010. The TSIM-plough resolved three problems encountered by the original Three-stage Subsoil Mixing Plough (hereafter, TSM-plough) developed in 1996. In this paper, the improved soil penetration resistance (trafficability) and crop yields in the field operated with this TSIM-plough are discussed. The new plough produced greater soil penetration resistance, and so greater trafficability of vehicles. The difference of the soybean yield was small between the TSM-plough and the TSIM-plough, and so the usage of the TSIM-plough is preferred.