Influence of some bio-products on the biological and productive characteristics of bird’s foot trefoil grown for forage

During the 2010-2012 period the influence of some bioproducts being mainly a combination of macro and micronutrients at different concentrations on the productivity, botanical and morphological composition of bird’s foot trefoil swards was studied. The experiment was carried out on the experimental field of the IMSA - Troyan by the completely randomized method with 4 replications and harvest plot size of 5 m2. Four bio-products phosphorus humate in dose of 3000 l/ha, boron humate (1600 l/ha) and molybdenum humate (1600 l/ha) and their combination phosphorus humate (2500 l/ha) + boron humate (1000 l/ha) + molybdenum humate (1000 l/ha) were studied. They were applied at the 2-4 leaf. The results showed that solely phosphorus humate had a positive influence, which increased the dry matter yield only by 8.7% and the results were not statistically significant.. It was found that the data had a unidirectional character with regard to the leafiness degree during the years as a result of the applied bio-fertilizers. Their application had a positive effect on the leafiness. The phosphorus humate showed a tendency to increase the relative portion of stems in the sward from the first to the third year. The kind of the applied bio-fertilizers was not of substantial importance to the degree of stem growth and botanical composition of the sward.