Influence of Decrease in Stolon Number Caused by Low Temperature on Yield of Ladino White Clover Sward

[摘要] In order to make clear the reality of winter injury of forage crops in the Apline Resion of Central Japan, the aspect of decrease in stolon number caused by low temperature during winter and early spring season and the influence of it on yield in the sward of Ladino white clover (Trifolium repens L.) which is the most sensitive plant to winter injury among forage crops were studied in this experiment. The following results were obtained. 1) The remarkable decrease in stolon number of Ladino white clover was observed in early spring season rather than during winter season. 2) The stolon number reduction which occured in early spring were caused by the cutting and heaving of root and soil erosion by the alternate freezing and thawing in the upper soil layer and by the direct cold injury to bare stolon originated in the frequent alternation of air temperature at above and below freezing point in this season. 3) The cutting yields in the sward from spring to summer and the intervals to recovery in yield from winter injury were proportional to the reduction rates of stolon number in early spring. 4) There were significantly high correlations between the reduction rate of stolon number in early spring or the stolon number at the first cutting time and total dry matter yield per year respectively. These results seem to show that total dry matter yield of Ladino white clover sward in a year is influenced by the reduction of stolon number in early spring. 5) The correlation coefficients between yield in each cutting time and total yield a year showed a tendency to decrease with the advancement of cutting time. And there was not a significant correlation between both factors at the last cutting time in autumn season (Fig. 5). These facts indicate that total yield a year of Ladino white clover sward in Alpine Region of Central Japan is influenced by the amount of yield from spring to summer, that is, by the intensity of winter injury to stolon of this plant.

[学科分类] 农业科学（综合）