Abstract
In this study some technological assessments were made about the sward surface cultivation at the sod-seeding, coverage removing by defoliations and nitrogen applications after seeding in relation to their influences on the regrowth of existing timothy and the establishment of sod-seeded red clover. 1. The partial cultivation of sward surface using slot-seeder, John Deere Powr-Till Seeder, and the whole cultivation using disk-harrow or rotary-harrow offered good seed-bed for sod-seeded red clover. The suppression effect on existing timothy by surface cultivation varied according to the cultivation methods. Since the whole cultivation gave a great suppression to the regrowth of timothy through the physical damage, the sward turned red clover dominant by the fall. On the other hand, the partial cultivation did not sufficiently suppress the growth of existing timothy and the considerably vigorous regrowth of timothy was found. Consequently, the ratio of red clover could not attain to an adequate level until second harvest of following year. 2. the temperate defoliation of the surrounding grasses after red clover sowing accelerated the growth of red clover plants, especially in the combination of sod-seeding with the partial cultivation method. The nitrogen application in the following spring decreased the ratio of red clover. The joint effect of defoliation of surrounding grasses and application of nitrogen was regarded very important as post-sowing management for promoting the establishment of red clover.
