Studies on Competition between Grass and Legume in Mixed Sward : VI. Effects of the growth stage and the temperature on the upward growth of orchardgrass and Ladino clover in summer.

[摘要] In order to clarify the effects of the growth stage and the temperature on the upward growth of orchardgrass and Ladino clover in summer, the tests were attempted on the two species grown separately in each own sward. The test results are summarilzed as follows: 1) The tiller number per square meter of orchardgrass was larger in spring, while smaller in summer. In spring, 70 to 90 per cent of all tillers were at the reproductive stage, while in summer, most of the tillers were at the vegetative stage. 2) Smallness in the tiller number in summer can be ascribed to the follwing two reasons: -(1): most of the tillers observed in spring have died out after heading by late June. (2): the tillering rate was lower in summer. 3) The plant height of tillers at the reproductive stage in spring was approximately twice as high as that at the vegetative stage in summer, while the plant height of the tillers at the vegitative stage showed almost no difference between spring and summer. 4) Judging from the facts stated in l), 2) and 3), it is concluded that the decrease in the upward growth rate of orchardgrass in summer can be ascribed to the fact that the tillers at the reprodutive stage have been replaced, by early summer, by the tillers which put forth at the vegetative stage. 5) The petiole length of Ladino clover was not related with the growth stage. With regard to the effect of the growth stage, it can be said that the flower buds which reached a peak of the formation in June-July months suppressed the formation of branches in the same season, thus resulting in the decrease in the stolon number per square meter in summer. 6) The petiole length was related with temperature. It has become longer according to the rise in summer temperature. 7) Judging from the facts stated in 5 and 6, it is concluded that the increase in upward growth rate of Ladino clover in summer can be ascribed chiefly to the high temperature in summer.

[学科分类] 农业科学（综合）