Abstract
Experiments were carried out to acertain the effect of size of clods in paddy soil on the growth of rice plants. The results obtained were as follows: 1. When there are a too large contet of small clods in the paddysoil, organic nitrogen changes into inorganic nitrogen rather rapidly, and at the same time the soil becomes reductive. 2. When there are contained much small clods in the paddy soil, especially vigorous growth of the plant takes place at first, but soon afterwards the root activity becomes apt to be retarded by the reductive condition of the soil. 3. The above mentioned characteristic of the soil tillage should always be taken in account by comparative consideration of power tilling and cattle plowing.
