Studies on the Grassland Development in the Forest VI. Effect of shading degrees on the correlations and the variations of agronomic characteristics in the shoot and root part of some grases

임간 초지 개발에 관한 연구 VI. 차광정도에 따른 주요목초의 지상부 및 지하부의 생육형질 변이와 그 상관관계

This study was carried out to investigate the relationships and the variations of agronomic characteristics in the shoot and root part of grasses for the basic data of the development, the management and the utilization of pasture in the forest. This study was conducted with 0% (full sunlight), 25%, 50% and 75% of shading degrees after orchardgrass, timothy, perennial ryegrass, ladino clover and orchardgrass dominated mixture were planted on Aug. 25 in 1984. The results are summarized as follows: 1. Dry matter yield in 25% of shading was increased 3-1 7% compared with 0% (full sunlight), while 50 and 75% of shading were decreased 28-35% and 44-60%, respectively. Dry matter yield of timothy, perennial ryegrass and ladino clover were decreased 10, 8 and 33%, respectively, compared with orchardgrass, but there was little difference between orchard grass and mixture. 2. Root distribution by different shading degrees was the maximum at 25%, followed by 0, 50 and 75% of shading degrees. Root distribution among different species was the maximum at orchardgrass, followed by perennial ryegrass and timothy. Especially, root distribution of timothy was very little compared with different species. And significantly positive correlation was observed in the relationship between root weight and dry matter yield (r=0.8 102**). 3. The physiological activity of root by different shading degrees was declined by more shading. 4. The length and the percentage of blade by different shading degrees was an increase tendency by more shading. The length and the percentage of blade among different species was followed by timothy, perennial ryegrass and orchardgrass, in that order. And the correlation between the percentage of blade and dry matter yield was significantly negative.