Abstract
In order to prevent D. ciliaris infestation into a sward, the effect of fertilizer application and cutting on the growth of D. ciliaris was evaluated.
The results obtained are as follows.
1. During the period with high air temperature from July to August, D. ciliaris showed a remarkable increase in plant height, in contrast to other grasses such as orchardgrass and tall fescue (Fig. 2).
2. In a sward in which the area of bare ground was kept minimum by the application of low levels of fertilizer in the summer and cutting performed at 8 week intervals from July through October, D. ciliaris infestation was inhibited, a high yield of grass was obtained and a high population density of grasses was maintained. There was a negative correlation between the annual yield of D. ciliaris and both the annual grass yield and maintenance rate of grasses including five species such as orchardgrass, perennial ryegrass, tall fescue, redtop and Kentucky bluegrass.
3. Infestation of D. ciliaris into a sward resulted in the decrease of the total production of grasses after July, and intensified the seasonal trend of decreased production of grasses in summer and autumn (Fig. 4). Though the digestibility of D. ciliaris in July and August was superior to that of orchardgrass and tall fescue, it was lower in September and October. The number of calories and content of crude protein of D. ciliaris in July and October showed low values compared with the corresponding values for the grasses (Table 4).
4. Discontinuation of cutting during on 8 week period after early July, seemed to be on effective means to prevent D. ciliaris infestation into the sward (Table 5).
