With a purpose of finding out the effects of cattle slurry applicatioin on the dry matter yield, yield component, and botanical composition in the mixed sward, a field experiment was conducted with two times and five levels of cattle slurry application. The experimental field was laid.out in a split-plot design with three replications, and lasted from September. 1986 to October, 1990 at the Livestock Experiment Station in Suweon, The results obtained are summarized as follows: 1. At each harvest time, the plant growth of the plots with cattle slurry application was slightly worse when compared to dressing of mineral fertilizer. 2. Average dry matter yield for 4 years was not significantly different between the slurry application times, just after cutting, and 15 days after cutting, The DM yield in the plot with cattle slurry 30 m!/ha and mineral fertilizer(9,095 kg/ha) and with cattle slurry 60 m1/ha and mineral fertilizer(8, 987 kg/ha) were decreased by 8% and 10% than that of the plot with mineral fertilizer application(9,937 kg/ha), respectively. 3. The DM yield component of the plots with cattle slurry application just after cutting was much better when compared to manuring 15 days after cutting. And it was much better in the plot with cattle slurry 60 m"/ha and mineral fertilizer which was composed of 73.8% grasses(6.636 kg/ha). 24.6% legumes (2,207 kdha) and 1.6% weeds(144 kdha). 4. In general, the botanical composition was relatively good in the plots with slurry application just after cutting. Grassland vegetation of the plots with cattle slurry 60 m"/ha and mineral fertilizer was changed into much better botanical composition with 66.8% grasses, 30.2% legumes and 3. 1% weeds at the end of the experiment.xperiment.