Perennial Ryegrass

Abstract

This experiment was carried out to investigate seasonal variations in the plant growth and botanical composition of the mixture swards of orchardgrass/perennial ryegrass/Ladino clover sown at different seeding rates of perennial ryegrass. Five kinds of seeds mixture of orchardgrass 20 ㎏/㏊ Ladino clover 3 ㎏/㏊ added with 0 ㎏/㏊ (P-0), 5 ㎏/㏊(P-5), 10 ㎏/㏊(P-10), 20 ㎏/㏊(P-20) and 30 ㎏/㏊(P-30) of perennial ryegrass were sown in the experimental field of Kangwon National University on the 24th of April in 1972. The experimental mixture swards were cut once a month from June to October in the First harvest year (1972) and from April to October in the second harvest year (1973). The results obtained were summarized as follows: 1. Establishment ratio of orchardgrass and Ladino clover showed a tendency to drop as the seeding rate of perennial ryegrass rises. Orchardgrass and Ladino clover seemed to be oppressed already one month after the sowing by perennial ryegrass which was vigorous in early stage growth. 2. All the plants of the mixture shards had an inclination to show shorter plant length in spring and autumn, yet longer in summer. Perennial ryegrass showed comparatively little variation in the plant length throughout the growing period, while orchardgrass and Ladino clover marked large variation. 3. In the first harvest year, until the early summer the botanical composition ratio of perennial ryegrass marked 14.1% in P-5, 27.2% in P-10, 47.3% in P-20 and 63.7% in P-30 but after the midsummer the ratio dropped remarkably to 7.4%, 17.7%, 28.7% and 44.1% respectively. 4. Perennial ryegrass revealed poor summering and wintering record; it mostly disappeared after the midsummer of the second harvest year. 5. In the first harvest year, as seasons progressed from spring to autumn the ratio of perennial ryegrass in the botanical composition had a tendency to decrease in the plots sown under 10 ㎏/㏊ of perennial ryegrass but the ratio tended to increase in the plots sown more than 20 ㎏/㏊ of perennial ryegrass while the ratio of Ladino clover rised in every plots. 6. In the second harvest year, all through the growing seasons orchardgrass and Ladino clover maintained their botanical composition ration relatively equal except for the temporary dropping in orchardgrass` ratio in May and June and temporary rising in Ladino clover`s ratio in the same months. 7. Until the early summer of the second harvest year the botanical composition ratio inclined to drop in orchardgrass and Ladino clover and to rise in perennial ryegrass in proportion to increase in seeding rate of perennial ryegrass, but after that time difference of the botanical composition derived from the different seeding rates of perennial ryegrass was not noticed among the plots.