1988 Volume 57 Issue 4 Pages 608-613
Investigation on the storage root yield of sweet potato was carried out under different underground conditions by utilizing gravel culture. Roots were divided into three different functional parts: storage roots, roots developed from the stem (RA), and roots from the storage roots (RC). Different kinds of soil and soil moisture levels were applied to storage roots and different concentrations of culture solution were applied to RA and RC. These treatments were given during the thickening stage of storage roots. 1) Material plants grown by the gravel culture method exhibited normal growth. The yield in the control plot was higher than the yield obtained under the ordinary field conditions. 2) Application of a culture solution to RA and RC was more effective on storage root yield. On the other hand, the effect of soil and its moisture contents of storage roots was comparatively small on their yield and dry matter content. 3) The research results suggested that the direct effects of soil and its moisture contents on storage root were smaller than the effects of nutritional treatments on rootlet.
