Growth of sweet potato. - Especially on the case of different volumes of nitrogenous fertilizer.

1. I experimented to see how various amounts of nitrogenous manure gave the react upon the growth, yeild and component of the sweet potato provided with constant amount of phosphatic manure and potassium manure respectively, in sweet potato cultivation. 2. I found that the reaction of nitrogenous manure was scarce when sweet potatoes were gathered in early, but the later they were gathered in, the more remarkable was the reaction. 3. The growth of the sweet potato after August was not that of elongation but was that of corpulent. 4. It seemed that carbohydrate and protein made through assimilation in leaves were accumulated in the sweet potato mainly growing in its corpulent, in the later period of its growth. 5. When much nitrogenous manure had been given, the potato contained more starch and less glucose as its components. The amount of crude protein was also abundant in this case.