Abstract
To study the reasonable method of utilization in the soiling system of corn plants sown between late March and early August, their yield curves were presumed from their yield behavior. 1. On the assumption that corn is utilized in the soiling system, the cutting was made between the before tassel stage and the early milky stage, and the intervals between cutting periods were defined every five days in principle. 2. For plotting yield curve, the method of least squares was applied. Y was the fresh yield per 3.3m^2 and x the days lapse after the first cutting date. Each yield curve was shown by a linear or a quadratic equation. 3. The highest value of the fresh yield increase per day at the tassel stage of corn was observed in the plot sown in late April and the secondary value in that sown in June and the lowest value in that sown in August. 4. The serial utilization between June and October of soiling corn would be practicable, if corn could be sown in March, April, June, July and August. Their cutting periods and yield curves were as follows. Sowing on March 31st : The cutting was made from June 8 to July 8 and the yield curve was y=-0.18x^2+1.49x+13.76(0≦x≦6, 1x=5 days). Sowing on April 30th : The cutting was made from June 29 to July 29 and the yield curve was y=-0.273x^2+2.106 x+17.59 (0≦x≦6, 1x=5 days). Sowing on June 11th : The cutting was made from July 21 to August 25 and the yield curve was y=-0.455x^2+3.5x+8.4 (0≦x≦7, 1x=5 days). Sowing on July 12th : The cutting was made from August 20 to September 24 and the yield curve was y=1.408x+5.46 (0≦x≦7, 1x=5 days). Sowing on August 6th : The cutting was made from September 24 to October 29 and the yield curve was y=-0.257x^2+2.098x+8.29 (0≦x≦7, 1x=5 days).
