Effect of Organic Fertilizers on Botanical Composition of Grassland, Herbage Yield and Quality

The aim of this study was to assess the effects of organicfertilizers (cow manure + dung water; cattle slurry) applied in different annual doses of nitrogen (54, 84 and 120 kg/ha) by different intensities of grassland utilization (extensive – two cuts per year, medium intensive – three cuts per year, intensive – four cuts per year) on percentage of plant functional groups, dry matter yield, and forage quality. The study was performed on small-plot trial over 7 years on moderately moist grassland in the Czech Republic. The proportion of legumes was significantly higher in the treatments fertilized with cow manure + dung-water combined with medium intensive utilization and intensive utilization (10.2% and 10.3%, respectively). Fertilization significantly increased dry matter yields by 51.9% (cow manure + dung water) and 56% (cattle slurry) compared with unfertilized controls (4.81 t/ha). Grasslands fertilized with cattle slurry showed significantly higher concentration of crude protein (142.9 g/kg) compared with unfertilized (126.4 g/kg). Extensive grassland utilization significantly affected the increase of crude fibre concentration (up to 282.1 g/kg), and decrease of the energy value (up to 4.68 MJ g/kg of NEL). Organic matter digestibility was also negatively influenced by extensive grassland utilization (61.0%, 65.42% and 67.44% for the extensive, medium intensive and intensive utilization, respectively). Our findings suggested that medium intensive and intensive grassland utilization by the organic fertilization, which corresponded to annual doses of nitrogen of 84 and 120 kg/ha were the most suitable from the viewpoint of animal nutrition.