抄録
An experiment as to the spacing problem in sugar-cane has been studied under the conditions in temperate region. The results obtained on this experiment with Tekcha, Saccharum sinense, are summarized as follows; 1. During about 50 days after planting, the plant is in a preparatory period for settlement and development of the mother stalk until it becomes warm enough to enable the plant to tiller vigorously and to grow rapidly. The growing period continues for about 4 months until it becomes too cool to allow the plant to keep on vigorous growth, and then the plant transfers to the maturing stage which ranges over about 2 months from early Oct. to the harwesting period in Dec. In this period the plant mostly accumulates sugar in its stalk until the green leaf is seriously damaged by the prevailing low temperature, sometimes below the freezing point. 2. The growth curve of stalk length resembles to monomolecular autocatalytic reaction, and the length of stalk at given periods will be calculated from the following formula; [numerical formula] y is the stalk length in cm, and x is the number of days from June 2. to marked differences in the growth of stalk length are recognized among various plots of experiment. 3. The number of tillers increases up to the early Aug., and then is gradually decreases towards the maturing period, showing different rates of survived stalks according to the density of planting hills. 4. The area of a leaf and of total green leaves attains its maximum at late Aug., and then it decreases in the same way as in the numfer of green leaves per stalk. A larger extension of the area of total green leaves per stalk in the growing period, especially in later period, turns out a high content of sugar in harvested stalks. It is also pointed out that late Aug. seems to be very important period from physiological point of view, owing to the greatest number of green leaves and the largest area of totel green leaves per stalk are shown at this period. 5. The number of available stalks per unit area and the rate of perished stalks correlate possitively with the density of planting hills, while the reverse is the case between the density of planting hills and the number of available stalks and ratoons, each per hill. 6. Little comparable differences occur in the weight of a stalk among various plots of experiment, affirming that similar relationship should be secured with the weight of a stalk as was secured with the growth of stalk length. 7. The cane weight per hill is adversely proportionate to the density of planting hills. It means that the more the number of planting hills per unit area increase, the lower the efficiency for absorption of nutrients applied is. 8. A significant positive correlation between the cane yield per unit area and the density of planting hills is found. However, in is reasonably revealed that the cane yield per unit area reaches its maximum at the rate of 3, 600 hills per unit area, and is declines when more cuttings than that are planted to the same area. 9. The brix of pressed juice, on the other hand, lessens as the number of planting hills per unit area increases. Some suggestion as to a remedy for low brix in harvested stalks are referred to standpoints of introducing new improved varieties and applying calcium to the growing plant as a liguid manure in Aug. 10. The apparent sugar yield per unit area reaches its maximum at the rate of 3, 300 hills per unit area, and even so, it is revealed that a striking decrease in sugar yield will arise, if more hills than that are planted to the sane area. 11. Judging from the economical point of view, a profitable sugar yield per unit area may be produced at the spacing of 100 cm × 33 cm, or at the rate of about 3, 000 hills per unit area, in case of the monoculture of sugar-cane in this district. Remark: unit area in this eperiment is 0.25 acre. [the rest omitted]
