Influence of treatment with herbicides on the basic chemical composition on bird’s foot trefoil (Lotus corniculatus L.) swards

During the period 2020-2022 in the experimental field of Research Institute of Mountain Stockbreeding and Agriculture – Troyan, a research experiment with bird’s foot trefoil (Lotus corniculatus L.), cultivar Targovishte 1 was conducted to determine the impact of herbicide treatment on the basic chemical composition of the forage mass. The experiment was set up using the block method with the following variants: 1. Control- untreated (C); 2. Kalam at a dose of 20 g/da; 3. Kalam at a dose of 40 g/da 4. Focus ultra at a dose of 100 ml/da; 5. Focus ultra at a dose of 200 ml/da. Focus ultra herbicide (active substance cycloxydim 100 g/l) at the dose of 100 ml/da was found to exhibit positive effect on crude protein content, quantity of crude fats and mineral substances. The herbicide Kalam (dicamba 600 g/kg and tritosulfuron 125 g/kg) at a dose of 20 g/da stimulated the amount of the macroelement calcium to the highest extent, while its higher dose increased the phosphorus content in the biomass of bird’s foot trefoil. The two herbicides did not affect the amount of nitrogen free extractable substances (NFE). The favourable combination of high protein and low crude fiber determines the herbicide Focus Ultra at a dose of 100 ml/da as suitable for application in the practice.