Structural fiber components of cell walls after herbicide treatment of bird's foot trefoil stand

In the period 2020 – 2023, in the experimental field of Research Institute of Mountain Stockbreeding and Agriculture – Troyan, on light grey pseudopodzolic soil, a scientific experiment with bird's-foot trefoil (Lotus corniculatus L.), variety Targovishte 1, was conducted with the following treatments: 1. Control – untreated; 2. Kalam (20 g/da); 3. Kalam (40 g/da); 4. Focus ultra (100 ml/da); 5. Focus ultra - (200 ml/da) was conducted. The aim was to determine the structural fiber components of the cell walls and to calculate the nutritive value of the forage as a function of herbicide treatment. It was found that herbicides applied in the 2 - 4 leaf stage of bird's foot trefoil did not significantly affect the fiber composition of cell walls and the nutritional value of forage. Relatively favorable in terms of forage quality stood out those treated with Kalam herbicide at 20 g/da, due to the lowest values obtained for neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose, and the highest for hemicellulose, as well as the highest feed units for growth. Correlation analysis revealed the highest correlations between dry matter yield and the relative proportion of leaves (r = 0.833); between the relative proportion of stems in the stand and acid detergent lignin content (r = 0.829) and degree of lignification (r = 0.837); and between neutral detergent and acid detergent fiber (r = 0.940), allowing regression equations to be derived for predicting forage quality.