Improvement of planosol solum: Part 1, Experimental equipment, methods and preliminary soil bin experiments with ploughs

Abstract Based on field cultivation tests by Zhao and soil investigations by Araya, a one to one mixing of the second (Aw) and third (B) horizons was conducted to improve the planosol solum in China, leaving the first (Ap) horizon undisturbed. This paper deals with basic soil bin tests of soil mixing with half size model ploughs in Japan. The results showed that stand-up and drop-down ploughs produced good soil mixing and required low draught forces. On the other hand, a fold-up plough could not mix the soil and required a high draught force because the furrow slices did not move smoothly over the plough.