Study of Regeneration of Ladino Clover : 2. Regeneration of Ladino clover according to cutting intervals and its seasonal variation

[摘要] 1. A field test was carried out to clarify the effects of cutting intervals on the regrowing ability of Ladino clover after cutting in the warm area. Two treatments of cutting intervals, cuttings at 15-day intervals and at 30-day intervals, were given from April, and Ladino clover growing in community was tested on dry matter basis about three seasons; June, August and October. 2. Both plant height and dry matter production of Ladino clover were affected by cutting intervals, being higher at the 30-day intervals plot than at the 15-day intervals plot, arid at every seasonal investigation such effects on the regrowth could be recognized from about ten days after cutting. A ratio of leaves to total plant on dry matter weight was always higher at the 15-day intervals plot and the difference between the two plots became larger as cutting treatments were repeated showing to be the largest in October. As to an increasing rate of green leaf number, it wad higher at the 30-day intervals plot in case of October and folioles were longer as well. 3. At every seasonal investigation the 30-day intervals plot was superior to the 15-day intervals plot in an increasing rate of LAI after cutting and in its maximum value. Therefore, a decreasing rate of relative luminous intensity on the soil surface under Ladino clover community after cutting was larger in the 30-day intervals plot. In the correlation between LAI and relative luminous intensity, slopes of the regression lines differed according to cutting intervals, and from this fact it was inferred that some changes in the form of Ladino clover community might have been brought by varying its cutting intervals. 4. In each season a significant negative correlation was found at the level of 1 % between NAR and LAI and the regression. coefficient was varied according to cumulative frequency of cutting. In June when Ladino clover grew vigorously and had, not been subjected to cuttings so often, the 15-day intervals was superior to the 30-day intervals in an increasing rate of CGR and in its absolute value. On the contrary, in August and in October when the plant had suffered from repeated cutting treatments and its growth was not so vigorous under unfavorable surrounding conditions, the 30-day intervals was superior. 5. Carbohydrate contents in the tip of runners. (part between first node and third one) decreased rapidly immediately after cutting, but regained in about 25 days after cutting. In this case, Ladino clover in the 30-day intervals plot showed more rapid regaining and it accumulated more amount of carbohydrate in runners, compared with that of the 15-day intervals plot. 6. Choice of suitable cutting time of Ladino clover should be judged, not only from the apparent status of the growth but also from the consideration of the regrowing ability after cutting. In this test, cutting of the 30-day intervals was superior in productivity to that of the 15-day intervals, with higher assimilation and storing abilities of carbohydrate.

[学科分类] 农业科学（综合）