Studies on the Growing Process of Potato Plant : V. The effects of various combinations of spacing of hills, amounts of fertilizer and number of stem per tuber on the growth and yields

[摘要] 1) In order to obtain some fundamental informations for potato cultivation, the responses under various combinations of plant spacing, amounts of fertilizer and number of stem per tuber were investigated by using two varieties. 2) The dry-weight of top per hill increased proportionnally with the increase of the spacing-area of one plant. However, the larger the spacing-area is, the longer the time is taken to reach a given yield per unit area, thus the plants continuing the vegetative growth for a long time. Consequently, the tuber yields per unit area increased in proportion to the decrease of the spacing-area. 3) Factors influencing the tuber yields per unit area varied with the branching habits of potato varieties used. For Danshaku-imo (Irish Cobbler), a mild branching variety, the increase of either fertilizers or number of stem per tuber brought high yields as spacing of hills increased. While, for Norin No. 1, a highly branching variety, the increase of both fertilizers and number of stem per tuber was necessary to get high yields. 4) Four growth types were classified based on the difference between two parts of the stem which were divided at the 1st flower cluster, and it was found that there is a close relation between the growth type and the tuber yields, and there exists favourable growth type expecting high yields. 5) It was concluded that the regulation of the growth of potatoes by the combinations of spacing of hills, amounts of fertilizer and number of stem per tuber should be changed with the ecological characteristics of the varieties used.

[学科分类] 农业科学（综合）