Perennial ryegrass 의 파종비율 및 예취빈도가 혼파목초의 정착 및 성장에 미치는 영향 = Effects of Perennial Ryegrass Seeding Rate and Cutting Frequency on the Establishment and Growth of Pasture Plants of the Seeds Mixture

다국어 초록 (Multilingual Abstract)

An experiment was conducted to investigate how to effect the cutting frequency and perennial ryegrass seeding rate on the establishment and growth of the pasture plants in the swards of orchardgrass(20㎏/㏊)/Ladino clover(3㎏/㏊)mixture associated with perennial ryegrass at five different seeding rate of 0㎏/㏊, 5㎏/㏊, 10㎏/㏊, 20㎏/㏊ and 30㎏/㏊. The seeds mixtures were sown in April 1972 and the swards were cut at two different cutting frequency of 2-time/year and 4-time/year, and the experiment was carried out over a period of two years at Kangwon National Lniversity, Chunchon. The results obtained were summarized as follows: 1. Establishment ratio of orchardgrass was not dropped by adding perennial ryegrass up to 20㎏/㏊, yet the ratio was dropped notably by adding 30㎏/㏊ of the ryegrass. Establishment ratio of Ladino clover tended to drop as the seeding rate of the ryegrass increased. 2. In the first year, length of the pasture plants had a trend to shorten as the seeding rate of perennial ryegrass raised. But the effect of seeding rate of the ryegrass on the plants length was not found in the second year. 3. In summer season, perennial ryegrass seemed to be placed at a disadvantage in light competition since plant length of the ryegrass was shorter than that of orchardgrass by 20∼30㎝ in the 4-time cut plot and 50∼60㎝ in the 2-time cut plot. 4. In the 2-time cut plot, pasture plants lodged at every cut except the first cut in the first year. The lodging was due to such a excessively long plant length as 90∼110㎝ in orchardrass. It was too infrequent to cut two time in a year. 5. As the cutting frequency lowered, or the seeding rate of perennial ryegrass raised relative light intensity in the plant community had a tendency to descent. 6. During the summering period in the first year, decreasing rate of tiller or stolon number marked 27.5% in orchardgrass, 98.4% in perennial ryegrass and 41.0% in Ladino clover in the 2-time cut plot while 5.6% in orchardgrass, 89.1 in perennial ryegrass and 24.8% in the 4-time cut plot. The 2-time cut plot was remarkably higher than the 4-time cut plot in the decreasing rate of tiller or stolon number. 7. During the wintering period in the first year, orchardgrass increased by 56.8∼71.9% in tiller number and Ladino clover increased by 46.1∼99.0% in stolon number but the tiller number of perennial ryegrass were seemed to be decreased. Generally perennial ryegrass existed till spring time of the second year. 8. The seeding rate of perennial ryegrass assent density of orchardgrass and Ladino clover had a trend to drop in the first year, yet such a trend was not noticed in the second year. 9. In LAI of the mixture swards, the 2-time cut plot was larger than the 4-time cut plot (P$lt;0.05). The 2-time cut plot showed 9.94 and the 4-time cut plot showed 5.74 in the first year, and the 2-time cut plot showed 8.49 and the 4-time cut plot showed 6.31 in the second year. 10. In the first year, before the midsummer LAI of the mixture swards had a tendency to increase in proportion to rising the seeding rate of perennial ryegrass while after the midsummer it had a tendency to increase in proportion to decreasing the seeding rate of the ryegrass. 11. In the first year, LAI of the orchardgrass increased as the seeding rate of perennial ryegrass lowered. 12. When 20∼30㎏/㏊ of perennial ryegrass is added to the mixture early stage production of the sward expected to increase significantly.