Studies on Competition between Grass and Legume in Mixed Sward : V. Effects of regrowth period on the elongation of natural plant height of orchardgrass and Ladino clover after cutting in summer.

[摘要] In the present report, in order to clarify the effects of the pre-cutting-frepuency and the regrowth period on the light competition between orchardgrass and Ladino clover grown mixed in the same sward in summer, the effects of these factors on the elongation of the natural plant height of the two species in summer were tested. For this purpose, two test plots different in the cutting frequency in summer were set up respectively on each of the swards in which the two species were grown separately. In the case of the Test Plot A, the cutting was attempted four times during the period from June 12 to July 26, while in the case of Test Plot B, it was attempted two times during the same period. The natural plant height and the vertical distribution of LAI in both test plots were measured on the 31st day and 62nd day counting from the cutting date of July 26. The test results are summarized as follows: 1) It was clear that the elongation of the natural plant height of the two species was not affected by the pre-cutting frequency. Namely, no difference was observed in the natural plant height of the two species between the Test Plot A and B on either day of measurement, i. e., on the 31st day as well as on the 62nd day counting from the cutting date of July 26. 2) The two species were entirely different in the response of the plant height elongation to the regrowth period in summer. Namely, the elongation of the natural plant helght of Ladino clover exceeded that of orchardgrass in the early period after cutting on July 26 (in less than about 30 days), while that of orchardgrass came to exceed that of Ladino clover on the 60th day counting from the cutting date of July 26. 3) Accordingly, it is concluded that the differences of the light competition between the two species in summer (which were observed in the mixed sward different in the cutting frequency as stated in the previous report) can be ascribed to the differences of the response of elongation of the plant height of the two species to the regrowth period in the summer season.

[学科分类] 农业科学（综合）